Ovulation Calculator API
Ovulation Calculator estimates ovulation dates, fertile windows, and provides detailed cycle phase information based on menstrual cycle data.
The Ovulation Calculator API provides reliable and fast access to ovulation calculator data through a simple REST interface. Built for developers who need consistent, high-quality results with minimal setup time.
To use Ovulation Calculator, you need an API key. You can get one by creating a free account and visiting your dashboard.
GET Endpoint
https://api.apiverve.com/v1/ovulationcalculatorCode Examples
Here are examples of how to call the Ovulation Calculator API in different programming languages:
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"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);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)const https = require('https');
const url = require('url');
const options = {
method: 'GET',
headers: {
'X-API-Key': 'your_api_key_here',
'Content-Type': 'application/json'
}
};
const req = https.request('https://api.apiverve.com/v1/ovulationcalculator?last_period=2024-01-01&cycle_length=28', options, (res) => {
let data = '';
res.on('data', (chunk) => data += chunk);
res.on('end', () => console.log(JSON.parse(data)));
});
req.end();<?php
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://api.apiverve.com/v1/ovulationcalculator?last_period=2024-01-01&cycle_length=28');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET');
curl_setopt($ch, CURLOPT_HTTPHEADER, [
'X-API-Key: your_api_key_here',
'Content-Type: application/json'
]);
$response = curl_exec($ch);
curl_close($ch);
$data = json_decode($response, true);
print_r($data);
?>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))
}require 'net/http'
require 'json'
uri = URI('https://api.apiverve.com/v1/ovulationcalculator?last_period=2024-01-01&cycle_length=28')
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
request = Net::HTTP::Get.new(uri)
request['X-API-Key'] = 'your_api_key_here'
request['Content-Type'] = 'application/json'
response = http.request(request)
puts JSON.pretty_generate(JSON.parse(response.body))using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
class Program
{
static async Task Main(string[] args)
{
using var client = new HttpClient();
client.DefaultRequestHeaders.Add("X-API-Key", "your_api_key_here");
var response = await client.GetAsync("https://api.apiverve.com/v1/ovulationcalculator?last_period=2024-01-01&cycle_length=28");
response.EnsureSuccessStatusCode();
var responseBody = await response.Content.ReadAsStringAsync();
Console.WriteLine(responseBody);
}
}Authentication
The Ovulation Calculator API requires authentication via API key. Include your API key in the request header:
X-API-Key: your_api_key_hereInteractive API Playground
Test the Ovulation Calculator API directly in your browser with live requests and responses.
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) | - | |
cycle_length | integer | optional | Average menstrual cycle length in days Range: 21 - 35 |
Response
The Ovulation Calculator API returns responses in JSON, XML, YAML, and CSV formats:
Example Responses
{
"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."
}
}<?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>
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.
| 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. |
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 | - | |
cycle_length | number | - | |
ovulation | object | - | |
â”” date | string | - | |
â”” days_from_last_period | number | - | |
fertile_window | object | - | |
â”” start | string | - | |
â”” end | string | - | |
â”” duration_days | number | - | |
most_fertile_days | object | - | |
â”” start | string | - | |
â”” end | string | - | |
â”” duration_days | number | - | |
| [ ] Array items: | array[6] | - | |
â”” date | string | - | |
â”” day_relative_to_ovulation | number | - | |
â”” fertility_level | string | - | |
â”” description | string | - | |
next_period | object | - | |
â”” date | string | - |
Headers
Required and optional headers for Ovulation Calculator API requests:
| Header Name | Required | Example Value | Description |
|---|---|---|---|
X-API-Key | required | your_api_key_here | Your APIVerve API key. Found in your dashboard under API Keys. |
Accept | optional | application/json | Specify response format: application/json (default), application/xml, or application/yaml |
User-Agent | optional | MyApp/1.0 | Identifies your application for analytics and debugging purposes |
X-Request-ID | optional | req_123456789 | Custom request identifier for tracking and debugging requests |
Cache-Control | optional | no-cache | Control caching behavior for the request and response |
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.
Credit Cost: Each API called in your GraphQL query consumes its standard credit cost.
POST https://api.apiverve.com/v1/graphqlquery {
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.
CORS Support
The Ovulation Calculator API supports Cross-Origin Resource Sharing (CORS) with wildcard configuration, allowing you to call Ovulation Calculator directly from browser-based applications without proxy servers.
| CORS Header | Value | Description |
|---|---|---|
Access-Control-Allow-Origin | * | Accepts requests from any origin |
Access-Control-Allow-Methods | * | Accepts any HTTP method |
Access-Control-Allow-Headers | * | Accepts any request headers |
Browser Usage: You can call Ovulation Calculator directly from JavaScript running in the browser without encountering CORS errors. No proxy server or additional configuration needed.
Rate Limiting
Ovulation Calculator API requests are subject to rate limiting based on your subscription plan. These limits ensure fair usage and maintain service quality for all Ovulation Calculator users.
| Plan | Rate Limit | Description |
|---|---|---|
| Free | 5 requests/min | Hard rate limit enforced - exceeding will return 429 errors |
| Starter | No Limit | Production ready - standard traffic priority |
| Pro | No Limit | Production ready - preferred traffic priority |
| Mega | No Limit | Production ready - highest traffic priority |
Learn more about rate limiting →
Rate Limit Headers
When rate limits apply, each Ovulation Calculator response includes headers to help you track your usage:
| Header | Description |
|---|---|
X-RateLimit-Limit | Maximum number of requests allowed per time window |
X-RateLimit-Remaining | Number of requests remaining in the current window |
X-RateLimit-Reset | Unix timestamp when the rate limit window resets |
Handling Rate Limits
Free Plan: When you exceed your rate limit, Ovulation Calculator returns a 429 Too Many Requests status code. Your application should implement appropriate backoff logic to handle this gracefully.
Paid Plans: No rate limiting or throttling applied. All paid plans (Starter, Pro, Mega) are production-ready.
Best Practices for Ovulation Calculator:
- Monitor the rate limit headers to track your Ovulation Calculator usage (Free plan only)
- Cache ovulation calculator responses where appropriate to reduce API calls
- Upgrade to Pro or Mega for guaranteed no-throttle Ovulation Calculator performance
Note: Ovulation Calculator rate limits are separate from credit consumption. You may have credits remaining but still hit rate limits when using Ovulation Calculator on Free tier.
Error Codes
The Ovulation Calculator API uses standard HTTP status codes to indicate success or failure:
| Code | Message | Description | Solution |
|---|---|---|---|
200 | OK | Request successful, data returned | No action needed - request was successful |
400 | Bad Request | Invalid request parameters or malformed request | Check required parameters and ensure values match expected formats |
401 | Unauthorized | Missing or invalid API key | Include x-api-key header with valid API key from dashboard |
403 | Forbidden | API key lacks permission or insufficient credits | Check credit balance in dashboard or upgrade plan |
429 | Too Many Requests | Rate limit exceeded (Free: 5 req/min) | Implement request throttling or upgrade to paid plan |
500 | Internal Server Error | Server error occurred | Retry request after a few seconds, contact support if persists |
503 | Service Unavailable | API temporarily unavailable | Wait and retry, check status page for maintenance updates |
Learn more about error handling →
Need help? Contact support with your X-Request-ID for assistance.
Integrate Ovulation Calculator with SDKs
Get started quickly with official Ovulation Calculator SDKs for your preferred language. Each library handles authentication, request formatting, and error handling automatically.
Available for Node.js, Python, C#/.NET, and Android/Java. All SDKs are open source and regularly updated.
Integrate Ovulation Calculator with No-Code API Tools
Connect the Ovulation Calculator API to your favorite automation platform without writing code. Build workflows that leverage ovulation calculator data across thousands of apps.





All platforms use your same API key to access Ovulation Calculator. Visit our integrations hub for step-by-step setup guides.
Frequently Asked Questions
How do I get an API key for Ovulation Calculator?
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?
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.



