Menstrual Cycle Calculator API

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Overview

To use Menstrual Cycle Calculator, you need an API key. You can get one by creating a free account and visiting your dashboard.

View in Marketplace

GET Endpoint

URL

https://api.apiverve.com/v1/menstrualcycle

Example

How to call the Menstrual Cycle Calculator API in different programming languages.

cURL Request

curl -X GET \
  "https://api.apiverve.com/v1/menstrualcycle?last_period=2024-01-01&cycle_length=28&period_length=5&cycles=3" \
  -H "X-API-Key: your_api_key_here"

JavaScript (Fetch API)

const response = await fetch('https://api.apiverve.com/v1/menstrualcycle?last_period=2024-01-01&cycle_length=28&period_length=5&cycles=3', {
  method: 'GET',
  headers: {
    'X-API-Key': 'your_api_key_here',
    'Content-Type': 'application/json'
  }
});

const data = await response.json();
console.log(data);

Python (Requests)

import requests

headers = {
    'X-API-Key': 'your_api_key_here',
    'Content-Type': 'application/json'
}

response = requests.get('https://api.apiverve.com/v1/menstrualcycle?last_period=2024-01-01&cycle_length=28&period_length=5&cycles=3', headers=headers)

data = response.json()
print(data)

Go (net/http)

package main

import (
    "fmt"
    "io"
    "net/http"

)

func main() {
    req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/menstrualcycle?last_period=2024-01-01&cycle_length=28&period_length=5&cycles=3", nil)

    req.Header.Set("X-API-Key", "your_api_key_here")
    req.Header.Set("Content-Type", "application/json")

    client := &http.Client{}
    resp, err := client.Do(req)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()

    body, _ := io.ReadAll(resp.Body)
    fmt.Println(string(body))
}

Example Response

{
  "status": "ok",
  "error": null,
  "data": {
    "last_period_date": "2024-01-01",
    "cycle_length": 28,
    "period_length": 5,
    "cycles_calculated": 3,
    "cycles": [
      {
        "cycle_number": 1,
        "period": {
          "start_date": "2024-01-01",
          "end_date": "2024-01-05",
          "duration_days": 5
        },
        "ovulation": {
          "date": "2024-01-15",
          "day_of_cycle": 14
        },
        "fertile_window": {
          "start_date": "2024-01-10",
          "end_date": "2024-01-15",
          "duration_days": 6
        },
        "pms_phase": {
          "start_date": "2023-12-21",
          "end_date": "2023-12-31"
        },
        "cycle_phases": {
          "menstrual": {
            "start": "2024-01-01",
            "end": "2024-01-05",
            "description": "Menstruation"
          },
          "follicular": {
            "start": "2024-01-06",
            "end": "2024-01-14",
            "description": "Follicular phase - preparing for ovulation"
          },
          "ovulation": {
            "date": "2024-01-15",
            "description": "Ovulation - most fertile day"
          },
          "luteal": {
            "start": "2024-01-16",
            "end": "2024-01-28",
            "description": "Luteal phase - preparing for next period"
          }
        },
        "status": "past",
        "days_until": null,
        "days_ago": 715
      },
      {
        "cycle_number": 2,
        "period": {
          "start_date": "2024-01-29",
          "end_date": "2024-02-02",
          "duration_days": 5
        },
        "ovulation": {
          "date": "2024-02-12",
          "day_of_cycle": 14
        },
        "fertile_window": {
          "start_date": "2024-02-07",
          "end_date": "2024-02-12",
          "duration_days": 6
        },
        "pms_phase": {
          "start_date": "2024-01-18",
          "end_date": "2024-01-28"
        },
        "cycle_phases": {
          "menstrual": {
            "start": "2024-01-29",
            "end": "2024-02-02",
            "description": "Menstruation"
          },
          "follicular": {
            "start": "2024-02-03",
            "end": "2024-02-11",
            "description": "Follicular phase - preparing for ovulation"
          },
          "ovulation": {
            "date": "2024-02-12",
            "description": "Ovulation - most fertile day"
          },
          "luteal": {
            "start": "2024-02-13",
            "end": "2024-02-25",
            "description": "Luteal phase - preparing for next period"
          }
        },
        "status": "past",
        "days_until": null,
        "days_ago": 687
      },
      {
        "cycle_number": 3,
        "period": {
          "start_date": "2024-02-26",
          "end_date": "2024-03-01",
          "duration_days": 5
        },
        "ovulation": {
          "date": "2024-03-11",
          "day_of_cycle": 14
        },
        "fertile_window": {
          "start_date": "2024-03-06",
          "end_date": "2024-03-11",
          "duration_days": 6
        },
        "pms_phase": {
          "start_date": "2024-02-15",
          "end_date": "2024-02-25"
        },
        "cycle_phases": {
          "menstrual": {
            "start": "2024-02-26",
            "end": "2024-03-01",
            "description": "Menstruation"
          },
          "follicular": {
            "start": "2024-03-02",
            "end": "2024-03-10",
            "description": "Follicular phase - preparing for ovulation"
          },
          "ovulation": {
            "date": "2024-03-11",
            "description": "Ovulation - most fertile day"
          },
          "luteal": {
            "start": "2024-03-12",
            "end": "2024-03-24",
            "description": "Luteal phase - preparing for next period"
          }
        },
        "status": "past",
        "days_until": null,
        "days_ago": 659
      }
    ],
    "current_status": {
      "phase": "Unknown",
      "description": "",
      "next_period": null,
      "days_until_next_period": null
    },
    "averages": {
      "cycle_length": 28,
      "period_duration": 5,
      "days_between_periods": 28
    },
    "disclaimer": "This calculator provides estimates only. Actual cycles may vary. Consult a healthcare provider for medical advice."
  }
}

Authentication

The Menstrual Cycle Calculator API requires authentication via API key. Include your API key in the request header:

Required Header

X-API-Key: your_api_key_here

Learn more about authentication →

Interactive API Playground

Test the Menstrual Cycle Calculator API directly in your browser with live requests and responses.

Try Menstrual Cycle Calculator APIView details and test in the API marketplace

Parameters

The following parameters are available for the Menstrual Cycle Calculator API:

Calculate Menstrual Cycles

Parameter	Type	Required	Description	Default	Example
`last_period`	string	`required`	First day of last menstrual period (YYYY-MM-DD) Format: `date` (e.g., `2024-01-01`)	-	`2024-01-01`
`cycle_length`	integer	`optional`	Average cycle length in days Range: `21 - 35`	`28`	`28`
`period_length`	integer	`optional`	Average period duration in days Range: `2 - 10`	`5`	`5`
`cycles`	integer	`optional`	Number of future cycles to calculate Range: `1 - 12`	`3`	`3`

Response

The Menstrual Cycle Calculator API returns responses in JSON, XML, YAML, and CSV formats. The JSON response is shown in the Example section above; alternative formats below.

Other Response Formats

XML Response

200 OK

<?xml version="1.0" encoding="UTF-8"?>
<response>
  <status>ok</status>
  <error xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
  <data>
    <last_period_date>2024-01-01</last_period_date>
    <cycle_length>28</cycle_length>
    <period_length>5</period_length>
    <cycles_calculated>3</cycles_calculated>
    <cycles>
      <cycle>
        <cycle_number>1</cycle_number>
        <period>
          <start_date>2024-01-01</start_date>
          <end_date>2024-01-05</end_date>
          <duration_days>5</duration_days>
        </period>
        <ovulation>
          <date>2024-01-15</date>
          <day_of_cycle>14</day_of_cycle>
        </ovulation>
        <fertile_window>
          <start_date>2024-01-10</start_date>
          <end_date>2024-01-15</end_date>
          <duration_days>6</duration_days>
        </fertile_window>
        <pms_phase>
          <start_date>2023-12-21</start_date>
          <end_date>2023-12-31</end_date>
        </pms_phase>
        <cycle_phases>
          <menstrual>
            <start>2024-01-01</start>
            <end>2024-01-05</end>
            <description>Menstruation</description>
          </menstrual>
          <follicular>
            <start>2024-01-06</start>
            <end>2024-01-14</end>
            <description>Follicular phase - preparing for ovulation</description>
          </follicular>
          <ovulation>
            <date>2024-01-15</date>
            <description>Ovulation - most fertile day</description>
          </ovulation>
          <luteal>
            <start>2024-01-16</start>
            <end>2024-01-28</end>
            <description>Luteal phase - preparing for next period</description>
          </luteal>
        </cycle_phases>
        <status>past</status>
        <days_until xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
        <days_ago>715</days_ago>
      </cycle>
      <cycle>
        <cycle_number>2</cycle_number>
        <period>
          <start_date>2024-01-29</start_date>
          <end_date>2024-02-02</end_date>
          <duration_days>5</duration_days>
        </period>
        <ovulation>
          <date>2024-02-12</date>
          <day_of_cycle>14</day_of_cycle>
        </ovulation>
        <fertile_window>
          <start_date>2024-02-07</start_date>
          <end_date>2024-02-12</end_date>
          <duration_days>6</duration_days>
        </fertile_window>
        <pms_phase>
          <start_date>2024-01-18</start_date>
          <end_date>2024-01-28</end_date>
        </pms_phase>
        <cycle_phases>
          <menstrual>
            <start>2024-01-29</start>
            <end>2024-02-02</end>
            <description>Menstruation</description>
          </menstrual>
          <follicular>
            <start>2024-02-03</start>
            <end>2024-02-11</end>
            <description>Follicular phase - preparing for ovulation</description>
          </follicular>
          <ovulation>
            <date>2024-02-12</date>
            <description>Ovulation - most fertile day</description>
          </ovulation>
          <luteal>
            <start>2024-02-13</start>
            <end>2024-02-25</end>
            <description>Luteal phase - preparing for next period</description>
          </luteal>
        </cycle_phases>
        <status>past</status>
        <days_until xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
        <days_ago>687</days_ago>
      </cycle>
      <cycle>
        <cycle_number>3</cycle_number>
        <period>
          <start_date>2024-02-26</start_date>
          <end_date>2024-03-01</end_date>
          <duration_days>5</duration_days>
        </period>
        <ovulation>
          <date>2024-03-11</date>
          <day_of_cycle>14</day_of_cycle>
        </ovulation>
        <fertile_window>
          <start_date>2024-03-06</start_date>
          <end_date>2024-03-11</end_date>
          <duration_days>6</duration_days>
        </fertile_window>
        <pms_phase>
          <start_date>2024-02-15</start_date>
          <end_date>2024-02-25</end_date>
        </pms_phase>
        <cycle_phases>
          <menstrual>
            <start>2024-02-26</start>
            <end>2024-03-01</end>
            <description>Menstruation</description>
          </menstrual>
          <follicular>
            <start>2024-03-02</start>
            <end>2024-03-10</end>
            <description>Follicular phase - preparing for ovulation</description>
          </follicular>
          <ovulation>
            <date>2024-03-11</date>
            <description>Ovulation - most fertile day</description>
          </ovulation>
          <luteal>
            <start>2024-03-12</start>
            <end>2024-03-24</end>
            <description>Luteal phase - preparing for next period</description>
          </luteal>
        </cycle_phases>
        <status>past</status>
        <days_until xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
        <days_ago>659</days_ago>
      </cycle>
    </cycles>
    <current_status>
      <phase>Unknown</phase>
      <description></description>
      <next_period xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
      <days_until_next_period xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
    </current_status>
    <averages>
      <cycle_length>28</cycle_length>
      <period_duration>5</period_duration>
      <days_between_periods>28</days_between_periods>
    </averages>
    <disclaimer>This calculator provides estimates only. Actual cycles may vary. Consult a healthcare provider for medical advice.</disclaimer>
  </data>
</response>

YAML Response

200 OK

status: ok
error: null
data:
  last_period_date: '2024-01-01'
  cycle_length: 28
  period_length: 5
  cycles_calculated: 3
  cycles:
    - cycle_number: 1
      period:
        start_date: '2024-01-01'
        end_date: '2024-01-05'
        duration_days: 5
      ovulation:
        date: '2024-01-15'
        day_of_cycle: 14
      fertile_window:
        start_date: '2024-01-10'
        end_date: '2024-01-15'
        duration_days: 6
      pms_phase:
        start_date: '2023-12-21'
        end_date: '2023-12-31'
      cycle_phases:
        menstrual:
          start: '2024-01-01'
          end: '2024-01-05'
          description: Menstruation
        follicular:
          start: '2024-01-06'
          end: '2024-01-14'
          description: Follicular phase - preparing for ovulation
        ovulation:
          date: '2024-01-15'
          description: Ovulation - most fertile day
        luteal:
          start: '2024-01-16'
          end: '2024-01-28'
          description: Luteal phase - preparing for next period
      status: past
      days_until: null
      days_ago: 715
    - cycle_number: 2
      period:
        start_date: '2024-01-29'
        end_date: '2024-02-02'
        duration_days: 5
      ovulation:
        date: '2024-02-12'
        day_of_cycle: 14
      fertile_window:
        start_date: '2024-02-07'
        end_date: '2024-02-12'
        duration_days: 6
      pms_phase:
        start_date: '2024-01-18'
        end_date: '2024-01-28'
      cycle_phases:
        menstrual:
          start: '2024-01-29'
          end: '2024-02-02'
          description: Menstruation
        follicular:
          start: '2024-02-03'
          end: '2024-02-11'
          description: Follicular phase - preparing for ovulation
        ovulation:
          date: '2024-02-12'
          description: Ovulation - most fertile day
        luteal:
          start: '2024-02-13'
          end: '2024-02-25'
          description: Luteal phase - preparing for next period
      status: past
      days_until: null
      days_ago: 687
    - cycle_number: 3
      period:
        start_date: '2024-02-26'
        end_date: '2024-03-01'
        duration_days: 5
      ovulation:
        date: '2024-03-11'
        day_of_cycle: 14
      fertile_window:
        start_date: '2024-03-06'
        end_date: '2024-03-11'
        duration_days: 6
      pms_phase:
        start_date: '2024-02-15'
        end_date: '2024-02-25'
      cycle_phases:
        menstrual:
          start: '2024-02-26'
          end: '2024-03-01'
          description: Menstruation
        follicular:
          start: '2024-03-02'
          end: '2024-03-10'
          description: Follicular phase - preparing for ovulation
        ovulation:
          date: '2024-03-11'
          description: Ovulation - most fertile day
        luteal:
          start: '2024-03-12'
          end: '2024-03-24'
          description: Luteal phase - preparing for next period
      status: past
      days_until: null
      days_ago: 659
  current_status:
    phase: Unknown
    description: ''
    next_period: null
    days_until_next_period: null
  averages:
    cycle_length: 28
    period_duration: 5
    days_between_periods: 28
  disclaimer: >-
    This calculator provides estimates only. Actual cycles may vary. Consult a
    healthcare provider for medical advice.

CSV Response

200 OK

key	value
last_period_date	2024-01-01
cycle_length	28
period_length	5
cycles_calculated	3
cycles	[{cycle_number:1,period:{start_date:2024-01-01,end_date:2024-01-05,duration_days:5},ovulation:{date:2024-01-15,day_of_cycle:14},fertile_window:{start_date:2024-01-10,end_date:2024-01-15,duration_days:6},pms_phase:{start_date:2023-12-21,end_date:2023-12-31},cycle_phases:{menstrual:{start:2024-01-01,end:2024-01-05,description:Menstruation},follicular:{start:2024-01-06,end:2024-01-14,description:Follicular phase - preparing for ovulation},ovulation:{date:2024-01-15,description:Ovulation - most fertile day},luteal:{start:2024-01-16,end:2024-01-28,description:Luteal phase - preparing for next period}},status:past,days_until:null,days_ago:715},{cycle_number:2,period:{start_date:2024-01-29,end_date:2024-02-02,duration_days:5},ovulation:{date:2024-02-12,day_of_cycle:14},fertile_window:{start_date:2024-02-07,end_date:2024-02-12,duration_days:6},pms_phase:{start_date:2024-01-18,end_date:2024-01-28},cycle_phases:{menstrual:{start:2024-01-29,end:2024-02-02,description:Menstruation},follicular:{start:2024-02-03,end:2024-02-11,description:Follicular phase - preparing for ovulation},ovulation:{date:2024-02-12,description:Ovulation - most fertile day},luteal:{start:2024-02-13,end:2024-02-25,description:Luteal phase - preparing for next period}},status:past,days_until:null,days_ago:687},{cycle_number:3,period:{start_date:2024-02-26,end_date:2024-03-01,duration_days:5},ovulation:{date:2024-03-11,day_of_cycle:14},fertile_window:{start_date:2024-03-06,end_date:2024-03-11,duration_days:6},pms_phase:{start_date:2024-02-15,end_date:2024-02-25},cycle_phases:{menstrual:{start:2024-02-26,end:2024-03-01,description:Menstruation},follicular:{start:2024-03-02,end:2024-03-10,description:Follicular phase - preparing for ovulation},ovulation:{date:2024-03-11,description:Ovulation - most fertile day},luteal:{start:2024-03-12,end:2024-03-24,description:Luteal phase - preparing for next period}},status:past,days_until:null,days_ago:659}]
current_status	{phase:Unknown,description:,next_period:null,days_until_next_period:null}
averages	{cycle_length:28,period_duration:5,days_between_periods:28}
disclaimer	This calculator provides estimates only. Actual cycles may vary. Consult a healthcare provider for medical advice.

View in Marketplace

Response Structure

All API responses follow a consistent structure with the following fields:

Field	Type	Description	Example
`status`	string	Indicates whether the request was successful ("ok") or failed ("error")	`ok`
`error`	string \| null	Contains error message if status is "error", otherwise null	`null`
`data`	object \| null	Contains the API response data if successful, otherwise null	`{...}`

Learn more about response formats →

Response Data Fields

When the request is successful, the data object contains the following fields:

Field	Type	Sample Value	Description
`last_period_date`	string	`"2024-01-01"`	-
`cycle_length`	number	`28`	-
`period_length`	number	`5`	-
`cycles_calculated`	number	`3`	-
[ ] Array items:	array[3]	`Array of objects`	-
└ `cycle_number`	number	`1`	-
└ `period`	object	`{...}`	-
└ `start_date`	string	`"2024-01-01"`	-
└ `end_date`	string	`"2024-01-05"`	-
└ `duration_days`	number	`5`	-
└ `ovulation`	object	`{...}`	-
└ `date`	string	`"2024-01-15"`	-
└ `day_of_cycle`	number	`14`	-
└ `fertile_window`	object	`{...}`	-
└ `start_date`	string	`"2024-01-10"`	-
└ `end_date`	string	`"2024-01-15"`	-
└ `duration_days`	number	`6`	-
└ `pms_phase`	object	`{...}`	-
└ `start_date`	string	`"2023-12-21"`	-
└ `end_date`	string	`"2023-12-31"`	-

Headers

Only X-API-Key is required. Optional headers include Accept for response format negotiation (JSON, XML, or YAML), User-Agent, and X-Request-ID for request tracing. See all request headers →

GraphQL AccessALPHA

Access Menstrual Cycle Calculator through GraphQL to combine it with other API calls in a single request. Query only the menstrual cycle calculator data you need with precise field selection, and orchestrate complex data fetching workflows.

Test Menstrual Cycle Calculator in the GraphQL Explorer to confirm availability and experiment with queries.

Credit Cost: Each API called in your GraphQL query consumes its standard credit cost.

GraphQL Endpoint

POST https://api.apiverve.com/v1/graphql

GraphQL Query Example

query {
  menstrualcycle(
    input: {
      last_period: "2024-01-01"
      cycle_length: 28
      period_length: 5
      cycles: 3
    }
  ) {
    last_period_date
    cycle_length
    period_length
    cycles_calculated
    cycles
    current_status {
      phase
      description
      next_period
      days_until_next_period
    }
    averages {
      cycle_length
      period_duration
      days_between_periods
    }
    disclaimer
  }
}

Note: Authentication is handled via the x-api-key header in your GraphQL request, not as a query parameter.

Try in GraphQL Explorer GraphQL Documentation

CORS Support

The Menstrual Cycle Calculator API accepts cross-origin requests from any origin, so it can be called directly from browser-based applications without a proxy. See CORS support →

Rate Limiting

Menstrual Cycle Calculator requests are throttled per minute on the Free plan and unthrottled on paid plans. Exceeding the limit returns 429 Too Many Requests; rate-limit usage is reported in the X-RateLimit-Limit, X-RateLimit-Remaining, and X-RateLimit-Reset response headers. See per-plan limits and best practices →

Error Codes

The Menstrual Cycle Calculator API uses standard HTTP status codes — 200 on success, 400 for invalid parameters, 401 for missing or invalid keys, 403 for insufficient credits, 429 for rate-limit exhaustion, and 500/503 for server-side issues. Each error response includes an X-Request-ID header you can quote when contacting support. See full error handling guide →

SDKs for Menstrual Cycle Calculator

Official Menstrual Cycle Calculator packages on npm, PyPI, NuGet, and JitPack — plus a Postman collection and an OpenAPI spec. See the SDK guide →

JitPack

No-Code Integrations

Menstrual Cycle Calculator works with Zapier, Make, Pipedream, n8n, and Power Automate using the same API key. See setup guides →

Zapier

Make

Pipedream

n8n

Power Automate

Frequently Asked Questions

How do I get an API key for Menstrual Cycle Calculator?

Sign up for a free account at dashboard.apiverve.com. Your API key will be automatically generated and available in your dashboard. The same key works for Menstrual Cycle Calculator and all other APIVerve APIs. The free plan includes 1,000 credits plus a 500 credit bonus.

How many credits does Menstrual Cycle Calculator cost?

Each successful Menstrual Cycle Calculator API call consumes credits based on plan tier. Check the pricing section above for the exact credit cost. Failed requests and errors don't consume credits, so you only pay for successful menstrual cycle calculator lookups.

Can I use Menstrual Cycle Calculator in production?

The free plan is for testing and development only. For production use of Menstrual Cycle Calculator, upgrade to a paid plan (Starter, Pro, or Mega) which includes commercial use rights, no attribution requirements, and guaranteed uptime SLAs. All paid plans are production-ready.

Can I use Menstrual Cycle Calculator from a browser?

Yes! The Menstrual Cycle Calculator API supports CORS with wildcard configuration, so you can call it directly from browser-based JavaScript without needing a proxy server. See the CORS section above for details.

What happens if I exceed my Menstrual Cycle Calculator credit limit?

When you reach your monthly credit limit, Menstrual Cycle Calculator API requests will return an error until you upgrade your plan or wait for the next billing cycle. You'll receive notifications at 80% and 95% usage to give you time to upgrade if needed.

What's Next?

Continue your journey with these recommended resources

Browse All APIs

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Authentication Guide

Learn about API keys and security

Rate Limits

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Menstrual Cycle Calculator API

Overview

GET Endpoint

Example

Authentication

Interactive API Playground

Parameters

Calculate Menstrual Cycles

Response

Other Response Formats

Response Structure

Response Data Fields

Headers

GraphQL AccessALPHA

CORS Support

Rate Limiting

Error Codes

SDKs for Menstrual Cycle Calculator

No-Code Integrations

Frequently Asked Questions

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