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Need to know the date 90 days from now, or 3 months before a deadline, or one year after an event? Adding time to a date by hand means rolling over month ends and leap years correctly — where mistakes creep in. This tool adds or subtracts any combination of days, months and years and gives you the exact resulting date.
Enter a start date, choose add or subtract, set the days, months and years, and the result appears instantly.
Date Calculator: step-by-step worked example
- Start date
- October 12, 2026
- Operation
- Add (forward)
- Days
- 15
- Months
- 6
- Years
- 1
- 1
Turn years and months into months
Total months = Years × 12 + Months
1 × 12 + 6 = 18 months
- 2
Add the months (clamped to month end)
Same day number; if the target month is shorter, its last day is used
October 12, 2026 + 18 = April 12, 2028
- 3
Add the days
Result = Intermediate date ± Days
April 12, 2028 + 15 = April 27, 2028
- 4
Day of the week
Which weekday the result falls on
= Thursday
- StartOctober 12, 2026
- After months/yearsApril 12, 2028
- ResultApril 27, 2028
Good to know: Years/months are added first, then days — this order matters at month ends (31 Jan + 1 month = 28/29 Feb). For legal or payment deadlines, check whether the result lands on a weekend or holiday.
Date Calculator — how it works
How it works
You pick a start date, a direction (forward to add, back to subtract), and any mix of days, months and years. The tool applies them and returns the resulting calendar date, handling month lengths and leap years correctly.
Order and month-end behaviour
Years and months are applied first, then days. Month-end cases are handled sensibly: one month after 31 January lands on the last day of February (there's no 31 February), and adding a year to 29 February gives 28 February in a non-leap year.
Common uses
- Deadlines: the date 30, 60 or 90 days from now (contracts, returns, notice periods).
- Planning: a date a set number of months or years ahead or behind.
- Finance: maturity and due dates a fixed term from a start date.
- Reminders: anniversaries and follow-ups a fixed interval later.
For the gap between two known dates, a days-between-dates calculator is the companion tool; for a pure countdown, a days-until-date calculator.
Worked example
Start from 15 June 2026 and add 90 days: the tool rolls through the months — 15 days left in June, then July (31), August (31), and into September — landing on 13 September 2026. Doing this by hand, it's easy to miscount the 30- and 31-day months; the tool tracks them exactly. Subtracting instead, or adding whole months and years, follows the same logic: 3 months before a 15 June date is 15 March, and one year after 29 February 2024 is 28 February 2025 (no 29th that year).
N days from today (12 October 2026)
| Days | Date | Weekday |
|---|---|---|
| 7 | 19 October 2026 | Monday |
| 10 | 22 October 2026 | Thursday |
| 14 | 26 October 2026 | Monday |
| 15 | 27 October 2026 | Tuesday |
| 21 | 2 November 2026 | Monday |
| 30 | 11 November 2026 | Wednesday |
| 45 | 26 November 2026 | Thursday |
| 60 | 11 December 2026 | Friday |
| 90 | 10 January 2027 | Sunday |
| 100 | 20 January 2027 | Wednesday |
| 120 | 9 February 2027 | Tuesday |
| 180 | 10 April 2027 | Saturday |
| 365 | 12 October 2027 | Tuesday |
N months from today
The day of month is kept; if the target month is shorter, the last day of that month is used.
| Months | Date | Weekday |
|---|---|---|
| 1 | 12 November 2026 | Thursday |
| 2 | 12 December 2026 | Saturday |
| 3 | 12 January 2027 | Tuesday |
| 4 | 12 February 2027 | Friday |
| 6 | 12 April 2027 | Monday |
| 9 | 12 July 2027 | Monday |
| 12 | 12 October 2027 | Tuesday |
| 18 | 12 April 2028 | Wednesday |
| 24 | 12 October 2028 | Thursday |
Frequently asked questions
How do I add days to a date?+
Enter the start date, choose "add," and set the number of days (and optionally months and years). The tool returns the exact resulting date, handling month lengths and leap years.
How do I find a date a number of months ago?+
Enter the start date, choose "subtract," and set the months. Month-end cases are handled sensibly — for example one month before 31 March is the end of February.
What date is 90 days from today?+
Set today as the start date, add 90 days, and the tool gives the exact date — for 15 June 2026 that is 13 September 2026. It counts the differing month lengths for you.
How are month-end dates handled?+
Sensibly: adding a month to 31 January gives the last day of February (there is no 31 February), and adding a year to 29 February gives 28 February in a non-leap year.
Can I add days, months and years at once?+
Yes — set any combination. Years and months are applied first, then days, to give a predictable, correct result.
Does it work for subtracting time as well?+
Yes — choose the "subtract" direction to go backward from the start date by any number of days, months and years.
Related guides
- How to add or subtract days, months and years from a dateAdding a month to January 31st doesn't give you "February 31st" — here's the order calculations actually happen in, and why it matters.
- How many days until a date? Counting down correctlyCounting down to a deadline, trip or event means finding the day-level difference between today and a target date — direction and whether to include today both matter.
About this page
- Publisher:
- Kalkoro — Teknolojig Bilişim Teknolojileri A.Ş., İstanbul
- Written by:
- Ahmet Tur — Editor (Math, date & time, unit conversion, physics & chemistry, everyday tools)
- Reviewed by:
- Kübra Yıldız — Editor
Parameters come from official sources; the last update date is shown at the bottom of the page.
Spotted a wrong result? Use the "Report a bug" button at the top of the page; every report is reviewed.
How we calculate and our accuracy policy →
Results are for information only. For official matters the relevant authority's calculation prevails.
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