Ovulation Calculator API

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Overview

To use Ovulation 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/ovulationcalculator

Example

How to call the Ovulation Calculator API in different programming languages.

cURL Request

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

JavaScript (Fetch API)

const response = await fetch('https://api.apiverve.com/v1/ovulationcalculator?last_period=2024-01-01&cycle_length=28', {
  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/ovulationcalculator?last_period=2024-01-01&cycle_length=28', 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/ovulationcalculator?last_period=2024-01-01&cycle_length=28", 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": "2024-01-01",
    "cycle_length": 28,
    "ovulation": {
      "date": "2024-01-15",
      "days_from_last_period": 14
    },
    "fertile_window": {
      "start": "2024-01-10",
      "end": "2024-01-15",
      "duration_days": 6
    },
    "most_fertile_days": {
      "start": "2024-01-13",
      "end": "2024-01-15",
      "duration_days": 3
    },
    "fertile_days": [
      {
        "date": "2024-01-10",
        "day_relative_to_ovulation": -5,
        "fertility_level": "medium",
        "description": "Fertile"
      },
      {
        "date": "2024-01-11",
        "day_relative_to_ovulation": -4,
        "fertility_level": "medium",
        "description": "Fertile"
      },
      {
        "date": "2024-01-12",
        "day_relative_to_ovulation": -3,
        "fertility_level": "medium",
        "description": "Fertile"
      },
      {
        "date": "2024-01-13",
        "day_relative_to_ovulation": -2,
        "fertility_level": "high",
        "description": "Most fertile"
      },
      {
        "date": "2024-01-14",
        "day_relative_to_ovulation": -1,
        "fertility_level": "high",
        "description": "Most fertile"
      },
      {
        "date": "2024-01-15",
        "day_relative_to_ovulation": 0,
        "fertility_level": "high",
        "description": "Most fertile"
      }
    ],
    "next_period": {
      "date": "2024-01-29",
      "days_from_last_period": 28
    },
    "cycle_phases": {
      "follicular_phase": {
        "duration_days": 14,
        "description": "From first day of period to ovulation"
      },
      "ovulation": {
        "duration_days": 1,
        "description": "Egg is released from ovary"
      },
      "luteal_phase": {
        "duration_days": 14,
        "description": "From ovulation to next period"
      }
    },
    "current_status": {
      "current_phase": "Menstruation",
      "is_fertile": false,
      "days_until_ovulation": -701,
      "days_until_next_period": -687
    },
    "disclaimer": "This calculator provides estimates only. Actual ovulation may vary. Consult a healthcare provider for medical advice."
  }
}

Authentication

The Ovulation 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 Ovulation Calculator API directly in your browser with live requests and responses.

Try Ovulation Calculator APIView details and test in the API marketplace

Parameters

The following parameters are available for the Ovulation Calculator API:

Calculate Ovulation

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 menstrual cycle length in days Range: `21 - 35`	`28`	`28`

Response

The Ovulation 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>2024-01-01</last_period>
    <cycle_length>28</cycle_length>
    <ovulation>
      <date>2024-01-15</date>
      <days_from_last_period>14</days_from_last_period>
    </ovulation>
    <fertile_window>
      <start>2024-01-10</start>
      <end>2024-01-15</end>
      <duration_days>6</duration_days>
    </fertile_window>
    <most_fertile_days>
      <start>2024-01-13</start>
      <end>2024-01-15</end>
      <duration_days>3</duration_days>
    </most_fertile_days>
    <fertile_days>
      <fertile_day>
        <date>2024-01-10</date>
        <day_relative_to_ovulation>-5</day_relative_to_ovulation>
        <fertility_level>medium</fertility_level>
        <description>Fertile</description>
      </fertile_day>
      <fertile_day>
        <date>2024-01-11</date>
        <day_relative_to_ovulation>-4</day_relative_to_ovulation>
        <fertility_level>medium</fertility_level>
        <description>Fertile</description>
      </fertile_day>
      <fertile_day>
        <date>2024-01-12</date>
        <day_relative_to_ovulation>-3</day_relative_to_ovulation>
        <fertility_level>medium</fertility_level>
        <description>Fertile</description>
      </fertile_day>
      <fertile_day>
        <date>2024-01-13</date>
        <day_relative_to_ovulation>-2</day_relative_to_ovulation>
        <fertility_level>high</fertility_level>
        <description>Most fertile</description>
      </fertile_day>
      <fertile_day>
        <date>2024-01-14</date>
        <day_relative_to_ovulation>-1</day_relative_to_ovulation>
        <fertility_level>high</fertility_level>
        <description>Most fertile</description>
      </fertile_day>
      <fertile_day>
        <date>2024-01-15</date>
        <day_relative_to_ovulation>0</day_relative_to_ovulation>
        <fertility_level>high</fertility_level>
        <description>Most fertile</description>
      </fertile_day>
    </fertile_days>
    <next_period>
      <date>2024-01-29</date>
      <days_from_last_period>28</days_from_last_period>
    </next_period>
    <cycle_phases>
      <follicular_phase>
        <duration_days>14</duration_days>
        <description>From first day of period to ovulation</description>
      </follicular_phase>
      <ovulation>
        <duration_days>1</duration_days>
        <description>Egg is released from ovary</description>
      </ovulation>
      <luteal_phase>
        <duration_days>14</duration_days>
        <description>From ovulation to next period</description>
      </luteal_phase>
    </cycle_phases>
    <current_status>
      <current_phase>Menstruation</current_phase>
      <is_fertile>false</is_fertile>
      <days_until_ovulation>-701</days_until_ovulation>
      <days_until_next_period>-687</days_until_next_period>
    </current_status>
    <disclaimer>This calculator provides estimates only. Actual ovulation may vary. Consult a healthcare provider for medical advice.</disclaimer>
  </data>
</response>

YAML Response

200 OK

status: ok
error: null
data:
  last_period: '2024-01-01'
  cycle_length: 28
  ovulation:
    date: '2024-01-15'
    days_from_last_period: 14
  fertile_window:
    start: '2024-01-10'
    end: '2024-01-15'
    duration_days: 6
  most_fertile_days:
    start: '2024-01-13'
    end: '2024-01-15'
    duration_days: 3
  fertile_days:
    - date: '2024-01-10'
      day_relative_to_ovulation: -5
      fertility_level: medium
      description: Fertile
    - date: '2024-01-11'
      day_relative_to_ovulation: -4
      fertility_level: medium
      description: Fertile
    - date: '2024-01-12'
      day_relative_to_ovulation: -3
      fertility_level: medium
      description: Fertile
    - date: '2024-01-13'
      day_relative_to_ovulation: -2
      fertility_level: high
      description: Most fertile
    - date: '2024-01-14'
      day_relative_to_ovulation: -1
      fertility_level: high
      description: Most fertile
    - date: '2024-01-15'
      day_relative_to_ovulation: 0
      fertility_level: high
      description: Most fertile
  next_period:
    date: '2024-01-29'
    days_from_last_period: 28
  cycle_phases:
    follicular_phase:
      duration_days: 14
      description: From first day of period to ovulation
    ovulation:
      duration_days: 1
      description: Egg is released from ovary
    luteal_phase:
      duration_days: 14
      description: From ovulation to next period
  current_status:
    current_phase: Menstruation
    is_fertile: false
    days_until_ovulation: -701
    days_until_next_period: -687
  disclaimer: >-
    This calculator provides estimates only. Actual ovulation may vary. Consult
    a healthcare provider for medical advice.

CSV Response

200 OK

key	value
last_period	2024-01-01
cycle_length	28
ovulation	{date:2024-01-15,days_from_last_period:14}
fertile_window	{start:2024-01-10,end:2024-01-15,duration_days:6}
most_fertile_days	{start:2024-01-13,end:2024-01-15,duration_days:3}
fertile_days	[{date:2024-01-10,day_relative_to_ovulation:-5,fertility_level:medium,description:Fertile},{date:2024-01-11,day_relative_to_ovulation:-4,fertility_level:medium,description:Fertile},{date:2024-01-12,day_relative_to_ovulation:-3,fertility_level:medium,description:Fertile},{date:2024-01-13,day_relative_to_ovulation:-2,fertility_level:high,description:Most fertile},{date:2024-01-14,day_relative_to_ovulation:-1,fertility_level:high,description:Most fertile},{date:2024-01-15,day_relative_to_ovulation:0,fertility_level:high,description:Most fertile}]
next_period	{date:2024-01-29,days_from_last_period:28}
cycle_phases	{follicular_phase:{duration_days:14,description:From first day of period to ovulation},ovulation:{duration_days:1,description:Egg is released from ovary},luteal_phase:{duration_days:14,description:From ovulation to next period}}
current_status	{current_phase:Menstruation,is_fertile:false,days_until_ovulation:-701,days_until_next_period:-687}
disclaimer	This calculator provides estimates only. Actual ovulation 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`	string	`"2024-01-01"`	-
`cycle_length`	number	`28`	-
`ovulation`	object	`{...}`	-
└ `date`	string	`"2024-01-15"`	-
└ `days_from_last_period`	number	`14`	-
`fertile_window`	object	`{...}`	-
└ `start`	string	`"2024-01-10"`	-
└ `end`	string	`"2024-01-15"`	-
└ `duration_days`	number	`6`	-
`most_fertile_days`	object	`{...}`	-
└ `start`	string	`"2024-01-13"`	-
└ `end`	string	`"2024-01-15"`	-
└ `duration_days`	number	`3`	-
[ ] Array items:	array[6]	`Array of objects`	-
└ `date`	string	`"2024-01-10"`	-
└ `day_relative_to_ovulation`	number	`-5`	-
└ `fertility_level`	string	`"medium"`	-
└ `description`	string	`"Fertile"`	-
`next_period`	object	`{...}`	-
└ `date`	string	`"2024-01-29"`	-

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

Test Ovulation 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 {
  ovulationcalculator(
    input: {
      last_period: "2024-01-01"
      cycle_length: 28
    }
  ) {
    last_period
    cycle_length
    ovulation {
      date
      days_from_last_period
    }
    fertile_window {
      start
      end
      duration_days
    }
    most_fertile_days {
      start
      end
      duration_days
    }
    fertile_days
    next_period {
      date
      days_from_last_period
    }
    cycle_phases {
      follicular_phase {
        duration_days
        description
      }
      ovulation {
        duration_days
        description
      }
      luteal_phase {
        duration_days
        description
      }
    }
    current_status {
      current_phase
      is_fertile
      days_until_ovulation
      days_until_next_period
    }
    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 Ovulation 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

Ovulation 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 Ovulation 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 Ovulation Calculator

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

JitPack

No-Code Integrations

Ovulation 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 Ovulation 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 Ovulation Calculator and all other APIVerve APIs. The free plan includes 1,000 credits plus a 500 credit bonus.

How many credits does Ovulation Calculator cost?

Each successful Ovulation 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 ovulation calculator lookups.

Can I use Ovulation Calculator in production?

The free plan is for testing and development only. For production use of Ovulation 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 Ovulation Calculator from a browser?

Yes! The Ovulation 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 Ovulation Calculator credit limit?

When you reach your monthly credit limit, Ovulation 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

Explore our complete catalog of APIs

Authentication Guide

Learn about API keys and security

Rate Limits

Understand usage limits and best practices

Was this page helpful?

Ovulation Calculator API

Overview

GET Endpoint

Example

Authentication

Interactive API Playground

Parameters

Calculate Ovulation

Response

Other Response Formats

Response Structure

Response Data Fields

Headers

GraphQL AccessALPHA

CORS Support

Rate Limiting

Error Codes

SDKs for Ovulation Calculator

No-Code Integrations

Frequently Asked Questions

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