🔌 Week Number API Explorer

Free REST API — No key required — CORS enabled — Try it live

Free No API Key CORS ✓ HTTPS JSON

GET /api/week Get the current week number

curl https://www.weeknumber.cc/api/week

GET /api/week?date={date} Get the week number for a specific date

date YYYY-MM-DD format

curl "https://www.weeknumber.cc/api/week?date=2026-12-25"

GET /api/week?year={year}&week={week} Get the date range for a specific week

year week

curl "https://www.weeknumber.cc/api/week?year=2026&week=25"

📝 Code Examples

JavaScript

Python

cURL

// JavaScript (browser or Node.js)
async function getWeekNumber() {
  const res = await fetch('https://www.weeknumber.cc/api/week');
  const data = await res.json();
  console.log(data.week_label); // "Week 25 of 2026"
  console.log(data.week_range); // { monday: "2026-06-15", sunday: "2026-06-21" }
  return data;
}

// With a specific date
async function getWeekForDate(date) {
  const res = await fetch(
    'https://www.weeknumber.cc/api/week?date=' + date
  );
  return res.json();
}

// Install: npm install weeknumber (coming soon)
// Or use the free API directly — no key needed!

# Python
import requests

# Get current week
resp = requests.get('https://www.weeknumber.cc/api/week')
data = resp.json()
print(data['week_label'])  # "Week 25 of 2026"
print(data['week'])        # 25
print(data['year'])        # 2026

# Get week for a specific date
resp = requests.get(
    'https://www.weeknumber.cc/api/week',
    params={'date': '2026-12-25'}
)
data = resp.json()
print(data['week'])  # Week of Christmas 2026

# Get date range for a week
resp = requests.get(
    'https://www.weeknumber.cc/api/week',
    params={'year': 2026, 'week': 1}
)
data = resp.json()
print(data['week_range'])  # {'monday': '...', 'sunday': '...'}

// Go
package main

import (
    "encoding/json"
    "fmt"
    "net/http"
)

type WeekResult struct {
    Date      string `json:"date"`
    Week      int    `json:"week"`
    Year      int    `json:"year"`
    WeekLabel string `json:"week_label"`
}

func main() {
    // Get current week
    resp, _ := http.Get("https://www.weeknumber.cc/api/week")
    defer resp.Body.Close()
    var result WeekResult
    json.NewDecoder(resp.Body).Decode(&result)
    fmt.Println(result.WeekLabel) // "Week 25 of 2026"
}

# cURL examples

# Get current week number
curl https://www.weeknumber.cc/api/week

# Get week number for a date
curl "https://www.weeknumber.cc/api/week?date=2026-12-25"

# Get date range for a specific week
curl "https://www.weeknumber.cc/api/week?year=2026&week=1"

# Response format:
# {
#   "date": "2026-06-20",
#   "week": 25,
#   "year": 2026,
#   "week_label": "Week 25 of 2026",
#   "week_range": { "monday": "...", "sunday": "..." },
#   "day_of_week": "Saturday",
#   "weeks_in_year": 53
# }

❓ FAQ

Is the API really free?

Yes! 100% free. No API key required. No rate limits (be reasonable). No registration needed.

Can I use it in production?

Yes! It runs on Cloudflare's global edge network. CORS is enabled for browser use. HTTPS only. If you need guaranteed uptime, consider self-hosting or caching the responses.

What week numbering system is used?

ISO 8601 standard. Weeks start on Monday. Week 1 is the week containing the first Thursday of the year.