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Free Date Calculator

Manage your schedule efficiently. Calculate the exact duration between two dates or determine a future date by adding days, weeks, or months.

Last Updated: 15 Jan 2026

Start Date

End Date

Enter dates to calculate

What is a Date Calculator?

A date calculator is a tool that performs date arithmetic—calculating the number of days between two dates or adding/subtracting days, weeks, or months from a specific date. It helps you determine future dates, calculate time differences, and plan deadlines or events with precise date calculations.

Date calculators are essential for project management, event planning, legal deadlines, financial calculations, and any situation requiring precise date calculations. They account for varying month lengths, leap years, and calendar complexities to provide accurate results.

Why Use Our Free Date Calculator?

Date Difference Calculation

Calculate exact number of days, weeks, or months between two dates. Get precise time differences for planning, deadlines, or duration calculations.

Future Date Planning

Add days, weeks, or months to any date to calculate future dates. Perfect for planning deadlines, events, or determining future dates accurately.

Past Date Calculation

Subtract days, weeks, or months to calculate past dates. Determine what date was X days ago or calculate historical dates.

Common Use Cases for Date Calculator

Project Management

Deadline Planning
Calculate sprint durations or exact deadline dates by adding 30/60/90 days to start dates. Plan project timelines and milestones accurately.
Duration Calculation
Calculate time between project start and end dates. Determine project duration, sprint lengths, or time-to-completion accurately.
Milestone Tracking
Calculate dates for project milestones, reviews, or checkpoints. Plan project phases and track progress with precise date calculations.

Personal & Professional

Event Planning
Countdown days until weddings, vacations, or launches. Calculate exact dates for event planning and countdown tracking.
Legal & Finance
Determine exact dates for contract expirations, interest periods, or payment deadlines. Calculate legal and financial dates accurately.
Subscription Management
Calculate renewal dates for subscriptions, memberships, or services. Determine when subscriptions expire or renew.

Practical Uses for Date Calculator

Project Management

Calculate sprint durations or exact deadline dates adding 30/60/90 days. Plan project timelines and track milestones accurately.

Example: Start date + 30 days = deadline date

Event Planning

Countdown days until a wedding, vacation, or launch. Calculate exact dates for event planning and preparation.

Example: Today + 60 days = event date

Legal & Finance

Determine exact dates for contract expirations or interest periods. Calculate legal and financial deadlines accurately.

Example: Contract start + 365 days = expiration

Date Calculation Tips

Inclusive vs Exclusive Days

The 'Diff' calculation counts full 24-hour periods between timestamps. Typically, if you want inclusive days (e.g., Mon to Fri is 5 days), add 1 to the result.

Tip: For business days or inclusive counting, adjust the result accordingly.

Subtracting Dates

Use the 'Add / Subtract' mode and select 'Subtract' to go back in time. Calculate what date was X days ago or determine past dates.

Example: Today - 90 days = date 90 days ago

Month Length Variations

Our calculator accounts for varying month lengths (28-31 days) and leap years. Adding months handles month transitions correctly.

Tip: Adding 1 month to Jan 31 correctly results in Feb 28/29 (or Mar dates).

Leap Year Handling

The calculator automatically accounts for leap years when calculating date differences or adding/subtracting days across leap year boundaries.

Note: Leap years add an extra day every 4 years (Feb 29).

Frequently Asked Questions

Does this include the end date?

The 'Diff' calculation counts the full 24-hour periods between timestamps. Typically, if you want inclusive days (e.g., Mon to Fri is 5 days), add 1 to the result.

Can I subtract dates?

Yes, use the 'Add / Subtract' mode and select 'Subtract' to go back in time (e.g., What date was 90 days ago?).

How accurate are the calculations?

Our calculator provides highly accurate date calculations that account for leap years, varying month lengths, and calendar complexities. Results are precise and handle edge cases correctly.

Can I calculate business days?

Our calculator calculates calendar days. For business days (excluding weekends/holidays), you'd need to manually adjust or use specialized business day calculators that exclude weekends and holidays.