How do I add or subtract time from a date?

Enter your starting date/time, select whether to add or subtract, enter the amount and unit (years, months, weeks, days, hours, minutes, seconds), and the result updates instantly.

Can I combine multiple time units?

Yes! You can add multiple time periods like '2 months and 15 days' by performing sequential calculations or using our combined input mode.

Does this account for leap years and varying month lengths?

Yes! The calculator automatically handles leap years (February 29), varying month lengths (28-31 days), and edge cases like adding months to January 31st.

How do I add days to a date — for example, 90 days from today?

Enter today's date in the start field, choose 'Add', enter 90, and select 'Days' as the unit. The calculator returns the exact date 90 days from now, accounting for month length variations and any DST transitions in the period.

Can I subtract years and months at the same time?

Yes. Run the operations in sequence — subtract the years first, then subtract the months from the result, or vice versa. The order generally does not matter except at month-end edge cases (e.g., subtracting 1 month from March 31 lands on Feb 28 or 29 depending on year).

Does the calculator handle Daylight Saving Time?

Yes. Adding 24 hours across a DST transition gives you the same clock time the next day, not 23 or 25 hours of elapsed time. Adding 1 day similarly preserves the local clock time. If you need exact elapsed time across DST, use the Duration Calculator instead.

What's the format for entering custom durations?

The calculator accepts shorthand like '1d 2h 30m' (1 day, 2 hours, 30 minutes), '90d' (90 days), or '6m 15d' (6 months 15 days). You can also use the dropdown unit selector for single-unit operations.

How is this different from the Duration Calculator?

Add/Subtract Time changes a date by a known amount and gives you the resulting date. Duration Calculator takes two known dates and tells you the time between them. Use Add/Subtract when you know the offset and need the date; use Duration when you know both dates and need the offset.

Date Calculator

Add or subtract years, months, weeks, days, hours, minutes, or seconds from any date. Perfect for deadline calculations, planning, and date math.

Starting Date & Time

Duration:

Operation:

Configure the calculation above to see results

How to Add or Subtract Time

Quickly calculate future or past dates by adding or subtracting years, months, days, hours, and minutes.

1. Set Start Date

Choose your reference point. Use "Now" for real-time calculations.

2. Pick Duration

Use quick presets like "1 year" or type a custom string like "2w 3d".

3. Toggle Operation

Switch between adding or subtracting time to find future or past dates.

Complex Date Logic

Our algorithm correctly handles varying month lengths, leap years, and daylight saving time transitions.

Example: Adding 1 month to January 31st correctly results in February 28th (or 29th in a leap year).

Explore More Tools

Duration Calculator Business Days Calc Age Calculator Unix Epoch Converter World Clock

Frequently Asked Questions

Why Use Our Date Add/Subtract Calculator?

Quick Presets

One-click durations from 15 minutes to 1 year.

Custom Durations

Add or subtract any combination of time units.

Add or Subtract

Calculate future dates or find past dates.

Export & Share

Export to calendar apps or share results instantly.

Add Subtract Date Calculator — Calculate Future or Past Dates

The add subtract date calculator is the fastest way to project any date forward or backward by a known amount of time. Add days to a date, subtract hours from a time, or build a complex deadline from a starting point — all without manual calendar counting or spreadsheet formulas.

Add Days, Hours, or Months to a Date

Use the calculator to add hours to time for shift scheduling, add days to a date for return policies, or add months for subscription renewals. Each operation handles month-length variations correctly — adding 1 month to January 31 returns Feb 28 (or 29 in a leap year), not an invalid Feb 31.

Subtract Days or Hours from a Date

Subtracting works the same way in reverse. Subtract days from date to figure out 'when did I start a 90-day fitness streak?' or subtract hours from time to find a meeting's send-out window. Useful for retroactive deadline math: 'My final deadline is March 15, my review needs to happen 5 business days earlier' — subtract 5 days, get March 10.

Deadline Calculator Mode

When you know the deadline and need to plan backwards, this tool acts as a deadline calculator. Enter the deadline date, choose 'Subtract', and enter how much lead time you need. The result is the latest you can start. Common patterns: '14 days before the event for invitation send', '30 days before the deadline for first draft', '90 days before launch for legal review'.

Common Calculations

Real-world examples that show the calculator's range.

Calculate future date

Add 90 days to today for a Net 90 invoice due date. Add 9 months for a pregnancy due date estimate. Add 1 year to a contract start for the renewal anniversary.

Calculate past date

Subtract 5 years from today to find your age 5 years ago in a specific date format. Subtract 30 days from a return-by date to find when an item was originally received.

Add hours to time

Add 8 hours to a shift start to find when the shift ends. Add 36 hours to a flight departure to find an arrival window with layovers. Add 72 hours to track a 3-day return policy.

Subtract hours from time

Subtract 3 hours from a meeting start to find when the prep call should happen. Subtract 24 hours from an airline cutoff to set your check-in reminder.

Date addition calculator

Combine multiple units in sequence — for example, add 2 months 15 days to a project kickoff to find the milestone review date, then add 30 more days for the final delivery.

Use Cases

How teams and individuals reach for this tool.

Invoice due dates (Net 30, Net 60, Net 90)

Set the invoice issue date as start, add the net days. Returns the exact due date, accounting for whether month-end falls on a weekend (use the Business Days Calculator if your terms specify business days rather than calendar days).

Project deadline math

Working backwards from a deadline to set milestone dates: '4 weeks before launch for code freeze, 2 weeks for QA, 1 week for soft launch'. Each subtraction gives you a milestone date.

Return policy windows

Add 30 days to a purchase date to find the latest valid return date. Useful for both buyers and customer-service teams checking eligibility.

Pregnancy due date estimation

Add 280 days (40 weeks) to the first day of the last menstrual period for the standard EDD calculation. Note: this is an estimate; consult a healthcare professional for medical decisions.

Subscription renewal tracking

Add 1 year, 1 month, or other recurring period to a subscription start date to find the next renewal. Useful for personal finance and SaaS billing audits.

Quick Presets Reference

The in-app preset buttons cover these common operations. Each preset is one click in the calculator above.

+1 day · Tomorrow's date at the same clock time.
+7 days · One week from today.
+30 days · Common Net 30 / monthly billing window.
+90 days · Quarterly review or extended return policy.
+1 month · Calendar month forward (handles month-end edge cases).
+1 year · Annual anniversary or contract renewal.
−7 days · One week ago.
−30 days · Last month's billing cutoff.
−1 year · Year-over-year comparison anchor.