Age in Weeks Calculator
Enter a birth date and calculate total completed weeks of age instantly.
Birth date
Enter one birth date per line using YYYY-MM-DD or MM/DD/YYYY.
Processing happens locally in your browser; nothing is uploaded.
Age in weeksTotal completed weeks from birth date to today.
Typical inputs process in under 1ms on modern browsers.
How to calculate age in weeks
Calculate in 3 steps
Takes ~5 seconds- 1Enter birth date
Type or paste a date in YYYY-MM-DD or MM/DD/YYYY format.
- 2Run calculator
Click "Calculate weeks" to total completed weeks.
- 3Use result
Copy the week count for your records.
Who should use this tool?
- Parents tracking age in weeks
- People measuring milestone timing
- Teams using week-based schedules
Examples
As of March 17, 2026, a 1990 birth date converts into this many completed weeks.
1990-07-15
1861
As of March 17, 2026, leap years are included automatically.
2000-02-29
1359
As of March 17, 2026, US-style numeric dates work too.
12/25/2010
794
Calculate age in weeks quickly
Use one birth date and return total completed weeks without manual date counting.
Use this age in weeks calculator to find total completed weeks from a birth date. Enter a birth date, calculate instantly, and copy the result for milestones, schedules, or age tracking. Everything runs locally in your browser for fast, private processing.
Convert a birth date into total completed weeks in one click.
- Completed weeks
- Instant output
- No server upload
Useful for baby milestones, planning, and comparisons.
- Single or bulk dates
- Copy ready
- Private calculation
Age in weeks tips
Use a valid full birth date for reliable week totals.
- Prefer YYYY-MM-DD for the clearest input format.
- Double-check month and day order for MM/DD/YYYY input.
- Use the age calculator if you need the leftover days too.
Frequently asked questions
Does this include leftover days?>
What date formats are supported?>
Is my birth date sent to a server?>
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