How to Calculate Days, Weeks & Months Between Dates

Need to know how many days, weeks, or months are between two dates? Our free date duration calculator instantly computes all time units with precision — perfect for project timelines, age tracking, or planning.

Step-by-Step Guide

Enter your start date in the first field.
Choose your end date in the second field.
Check “Include end date” to count the final day (e.g., for vacation length).
Toggle “Show years” to include year breakdown.
Click “Calculate Duration” to see results in days, weeks, months, and years.

Pro Tip:

Use this weeks between dates calculator for:

Pregnancy tracking (40 weeks = full term)
90-day notice periods
Quarterly reporting (13 weeks)
Fitness challenges (8-week programs)

Why Accurate Date Calculations Matter

Manual counting is prone to errors due to:

Leap years (366 days)
Months with 28, 30, or 31 days
Time zone differences
Inclusive vs. exclusive counting

This months between dates calculator handles all complexities automatically.

Real-World Use Cases

Project Management

Track sprint duration in weeks or total project months.

Pregnancy & Health

Monitor 280 days (40 weeks) of pregnancy progress.

Finance & Legal

Calculate exact billing cycles or contract months.

Personal Goals

Celebrate “6 months together” or “1000 days sober.”

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