# Date Difference Calculator

Calculate the exact number of days, weeks, months, and business days between two dates. Free online date difference calculator.

## What this calculates

Need to know exactly how many days are between two dates? This calculator computes the total days, weeks, approximate months and years, and even the number of business days (excluding weekends) between any two dates. Useful for project planning, contract deadlines, event countdowns, and more.

## Inputs

- **Start Year** — min 1900, max 2100
- **Start Month** — min 1, max 12
- **Start Day** — min 1, max 31
- **End Year** — min 1900, max 2100
- **End Month** — min 1, max 12
- **End Day** — min 1, max 31

## Outputs

- **Total Days**
- **Total Weeks**
- **Approximate Months**
- **Approximate Years**
- **Business Days (Mon-Fri)**

## Details

Enter the start and end dates using year, month, and day fields. The calculator handles the date order automatically, so it does not matter which date is earlier.

Results include:

  - Total days between the two dates (calendar days)

  - Total weeks (including fractional weeks)

  - Approximate months using the average month length of 30.4375 days

  - Approximate years using the average year length of 365.2425 days

  - Business days counting only Monday through Friday

The business day count excludes weekends but does not account for public holidays, which vary by country and region.

## Frequently Asked Questions

**Q: Does this calculator account for leap years?**

A: Yes. The calculator uses actual calendar dates, so leap years are automatically handled. February 29 is included in the count when it falls within the date range.

**Q: What are business days?**

A: Business days are weekdays (Monday through Friday), excluding Saturday and Sunday. This calculator counts business days but does not exclude public holidays.

**Q: Why are months and years approximate?**

A: Months vary from 28 to 31 days and years from 365 to 366 days. The calculator uses averages (30.4375 days/month, 365.2425 days/year) for a reasonable approximation. The total days count is always exact.

**Q: Does it matter which date I enter first?**

A: No. The calculator uses the absolute difference between the two dates, so the result is always a positive number regardless of which date is the start or end.

**Q: Can I use this for project deadline planning?**

A: Absolutely. Enter today's date as the start and your deadline as the end to see exactly how many calendar and business days you have remaining.

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Source: https://vastcalc.com/calculators/everyday/date-difference
Category: Everyday Life
Last updated: 2026-04-21