Find the number of days, weeks, months, or years between any two dates, or add/subtract time from any date.
Date calculations help you find future or past dates by adding or subtracting time periods.
Common Uses:
Calculation Notes:
Examples:
Type the start date using the date picker. The calculator accepts any date in the past, present, or future.
Add days, weeks, months, or years to the start date, or subtract them. We also support business days only, which skips weekends and common US holidays.
See the target date, the number of days between dates, and the day of the week. The date calculator handles month-length differences and leap years automatically.
For related calculations, try our age calculator.
Cross-checked against authoritative formulas (IRS, NIST, ACM) and updated for 2025/2026 tax years and rates.
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Each calculator includes the formula, plain-English explanation, and FAQs so you understand the result.
Estimates only. Calculator results are for educational and planning purposes — not professional advice. For binding decisions on taxes, investments, health, or legal matters, consult a qualified professional.
FAQ
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Count the days inclusively between any two dates. Our date calculator handles this and shows the count in days, weeks, months, and years. For example, January 1 to March 1 (same year) = 59 days. Our date calculator also accounts for leap years and the exact number of days in each month.
How it works
Our date calculator lets you find the number of days, weeks, months, or years between any two dates, or add or subtract a duration from a date, in three steps.
Pick the first date. The calculator uses this as day zero in the duration calculation.
Pick the end date to find the gap between them, or enter a number of days, weeks, months, or years to add or subtract from the start date.
The result shows the duration in days, weeks, months, and years, and lists the target date when adding or subtracting. Business days are counted separately when you toggle that option.