ChronoCalc API

Integrate chronological age calculation into your applications with our free REST API. No authentication required, no rate limits for reasonable use. Perfect for EHR systems, assessment platforms, and educational tools.

Endpoints

0ms

Auth Delay

JSON

Output Format

GET /api/calculate?birth=YYYY-MM-DD&target=YYYY-MM-DD

Calculate chronological age between two dates

Example Response

{
  "years": 8,
  "months": 3,
  "days": 12,
  "total_months": 99,
  "total_weeks": 431.1,
  "total_days": 3018,
  "formatted": "8 years, 3 months, 12 days"
}

GET /api/corrected?birth=YYYY-MM-DD&gestational=32.0&target=YYYY-MM-DD

Calculate corrected/adjusted age for premature infants

Example Response

{
  "chronological_age": "6 months, 2 weeks",
  "corrected_age": "4 months, 2 weeks",
  "weeks_premature": 8,
  "gestational_age_at_birth": 32
}

GET /api/pma?birth=YYYY-MM-DD&gestational=30.0&target=YYYY-MM-DD

Calculate post-menstrual age (PMA) for NICU

Example Response

{
  "pma_weeks": 41.7,
  "gestational_age_weeks": 30,
  "chronological_weeks": 11.7,
  "weeks_premature": 10,
  "term_equivalent": true
}

JavaScript Example

// Calculate chronological age
const birth = '2016-03-15';
const target = '2026-06-03';

fetch(`https://chronocalc.org/api/calculate?birth=${birth}&target=${target}`)
  .then(r => r.json())
  .then(data => {
    console.log(data.formatted); // "8 years, 3 months, 12 days"
    console.log(data.total_months); // 99
  });

// Calculate corrected age for preemie
fetch('https://chronocalc.org/api/corrected?birth=2024-01-15&gestational=32&target=2026-06-03')
  .then(r => r.json())
  .then(data => {
    console.log(data.corrected_age); // Corrected age string
  });

Usage Terms

The ChronoCalc API is free for personal, educational, and clinical use. Please include attribution with a link to chronocalc.org. For high-volume commercial use (over 10,000 requests/day), contact us. We reserve the right to implement rate limits if necessary to ensure service availability for all users.