Add Days Calculator
Add or subtract days from any date and get the new date, its weekday and the equivalent span in weeks and months instantly.
Whole days only.
Enter a valid date and a whole number of days.
Add Days Calculator on True Calculator gives you an instant, accurate answer with no sign-up and no app install. Add or subtract days from any date and get the new date, its weekday and the equivalent span in weeks and months instantly. Every result shows the formula and a worked example so you can verify the calculation yourself, and all values are computed in your own browser — your numbers never leave your device.
Popular uses: add days to date · days from date calculator · subtract days from date
Reviewed by the True Calculator team · Last updated: August 2026
How We Calculate
This calculator uses the standard Gregorian calendar with exact month lengths and leap-year rules. All calculations are performed instantly in your browser using JavaScript — no data is sent to any server.
Day and month counts follow the civil calendar used in official records. Leap years are handled automatically, and business-day counts follow the Monday-to-Friday convention.
When to Use This Calculator
Use the add days calculator whenever a date must be shifted by a plain number of calendar days — delivery dates, warranty end dates, notice periods, visa validity windows, ticket bookings and countdown planning. The add and subtract toggle covers forward and backward shifts with a single tool, and the output gives the exact resulting date, its weekday, and helpful week and approximate-month equivalents. Indian businesses use it for 30-60-90 day payment terms and delivery promises, while individuals rely on it for deadline maths like '90 days from today'. Because it counts every calendar day, it is the correct tool when weekends count; when only working days matter, pair it with the business-days calculator to keep schedules accurate.
How to Use This Calculator
- Step 1: Pick an operation — Add days or Subtract days — with the toggle at the top.
- Step 2: Enter a start date, such as 01-07-2026, in the start-date field.
- Step 3: Enter the number of whole days, such as 45, in the days field.
- Step 4: Read the resulting-date card for the new date and its weekday, plus the weeks and approximate months cards.
Worked Example
A merchant needs a delivery date 45 days after dispatch on 1 July 2026. Adding 45 days returns 15 August 2026, a Saturday — a 15 August that coincides with Independence Day that year. The weeks card shows 6 weeks plus 3 days, and the approximate months card shows 1.5 months using 30.44 days per month. For a 90-day warranty starting 15 January 2026, the calculator returns 15 April 2026, exactly 90 calendar days later.
Tips and Common Mistakes
- •Tip 1: Use subtract mode for reverse planning — find the date 30 days before a wedding or exam deadline.
- •Tip 2: The weeks and months cards are approximate aids; the resulting date itself is exact to the day.
- •Tip 3: If you need to skip weekends, use the business-days calculator instead — this one counts every calendar day.
- ✗Mistake 1: Assuming adding 30 days to a date lands on the same day next month — the result follows calendar days, not month boundaries.
- ✗Mistake 2: Entering decimals like 45.5 — the field accepts whole days, and fractional values are truncated.
Frequently Asked Questions
How do I add days to a date?
Pick a start date and enter the number of days to add. Adding 45 days to 1 July 2026 gives 15 August 2026, a Saturday, with the calculator showing the new date and its weekday. The count is by calendar days, so weekends and holidays are counted in — use the business-days calculator to skip them.
What is the date 90 days from now?
Enter today's date and 90 in the days field. For example, 90 days from 15 January 2026 is 15 April 2026. The 90-day window is common for visa validity, notice periods, trial periods and warranty claims in India, and the calculator returns the exact calendar date instead of counting manually.
How is this used for notice periods in India?
Employment contracts in India commonly specify 30, 60 or 90 days' notice. Enter your last working day or resignation date and add the notice length to find the release date. For a resignation effective 14 August 2026 with 30 days' notice, the calculator returns the exact final working date.
Can I subtract days too?
Yes — the subtract option steps the date backwards. Subtracting 45 days from 1 July 2026 returns 17 May 2026. This is useful for reverse calculations like finding the date 60 days before a wedding or exam, or computing eligibility windows that count back from a fixed event.
Does the result skip weekends?
No. This calculator shifts by plain calendar days, so a 45-day span from 1 July 2026 lands on 15 August 2026 whether that is a weekday or weekend. If you need the date after a number of working days, use the business-days calculator, which skips Saturdays and Sundays automatically.
You might also need
Related calculators from other categories
Construction
BTU Calculator
Calculate the BTU and AC tonnage required for a room based on size, sun exposure and insulation.
Construction
Concrete Calculator
Calculate concrete volume, weight and number of cement bags for a slab. Get exact quantities for your construction project.
Construction
Gravel Calculator
Estimate gravel volume, weight in tonnes and 50 kg bags for driveways and paths by material density.
Construction
Mulch Calculator
Work out mulch volume in m³ and litres, plus bags needed and cost for your garden beds.