Date Calculator - Add Subtract Days From Date Online
Add or subtract days, weeks, months, or years from a date — or find the difference between two dates.
How to use this calculator
👉 Fill in the boxes below and your answer appears instantly — no maths needed, we do it all for you! 🎉
In plain English — what does this do?
📊 A helper for daily life! Things like working out your age, how much to tip, what a sale price is, or how long until your birthday. Quick and easy answers for real life!
A date calculator lets you either add or subtract a span of time from a given date, or compute the exact difference between two dates. It's useful for project deadlines, scheduling, legal timeframes, and any situation where you need to know what date falls a certain number of days, weeks, months, or years away.
Result date
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What is Date Calculator - Add Subtract Days From Date Online?
A date calculator lets you either add or subtract a span of time from a given date, or compute the exact difference between two dates. It's useful for project deadlines, scheduling, legal timeframes, and any situation where you need to know what date falls a certain number of days, weeks, months, or years away.
How to use it
- 1️⃣ Choose a mode: 'Add / Subtract' to offset a date, or 'Difference' to measure the gap between two dates.
- 2️⃣ In Add/Subtract mode: pick a start date, enter the number of units, select the unit type, and choose whether to add or subtract.
- 3️⃣ In Difference mode: enter both a start date and an end date.
- 4️⃣ Results appear instantly below the inputs.
Formula
💡 See it in action — a real example
❓ Common questions
- Does the calculator account for leap years?
- Yes. All arithmetic uses the JavaScript Date object, which correctly handles leap years and varying month lengths.
- What does 'add 1 month' mean for January 31?
- Adding one month to January 31 yields February 28 (or 29 in a leap year) since February doesn't have 31 days. The date clamps to the last valid day of the resulting month.
- Can I calculate negative differences?
- In Difference mode, the calculator always returns the absolute difference regardless of which date is earlier.