How many days between two dates

From 1 January 2026 to 1 April 2026 the date difference calculator returns 90 calendar days between the dates, also 0 years, 3 months, 0 days in the Y/M/D breakdown. That is the direct answer. With weekends excluded, the same span shows 65 weekdays, counting both the start and end dates when they fall on Monday–Friday. The same tool can add or subtract a day count.

Three modes, one calculator

The date difference calculator exposes:

1. Difference: start date, end date, total days, weeks leftover, optional Y/M/D split, optional weekday-only count
2. Add days: start date + integer offset → result date
3. Subtract days: start date − integer offset → result date

There is no public-holiday calendar. “Exclude weekends” only drops Saturdays and Sundays in difference mode. If your deadline skips national holidays, you still need the official list.

Method

Difference mode parses both dates, orders them if you swapped start and end, then:

• Calendar day total = day distance from the earlier date to the later date (not an inclusive count of every date on both ends)
• Y/M/D comes from a calendar-aware year/month/day split
• With exclude weekends on, the weekday total counts Mondays–Fridays from the earlier date through the later date, including both ends when they are weekdays

Add/subtract modes apply the integer offset to the start date and return the resulting calendar date. They do not invent weekends-off logic for the shift itself.

Worked examples (locked to calculator output)

Difference

Inputs: start 2026-01-01, end 2026-04-01, weekends included.

Same dates with exclude weekends on: calendar days stay 90 between the dates, and the weekday count is 65 (both ends counted when they are weekdays).

Add 90 days

Start 2026-02-10, offset 90 → result date 2026-05-11.

Subtract 45 days

Start 2026-12-31, offset 45 → result date 2026-11-16.

These four runs match the calculator. Change any input in the embed below and the live tool will recompute the same way.

Why people still get this wrong

Hand counting “number of nights” versus “number of calendar days” causes off-by-one fights in travel and rentals. Inclusive business-day rules in legal forms are another trap: our weekday count is Monday–Friday only, not a court calendar.

Calendar months versus total days

The Y/M/D line for the sample is 0 years, 3 months, 0 days, while total days is 90. Those views answer different questions. “Three months later” follows calendar month boundaries; “ninety days later” is a fixed offset. February makes the gap obvious in other years: adding one calendar month is not the same as adding thirty days. Use the difference tab when you care about both views on one pair of dates, and use add/subtract when you only care about a day offset.

Weekends without holidays

On the sample span, excluding weekends yields 65 weekdays. That is useful for rough work estimates: how many office days sit between kickoff and a review. It is not a substitute for a holiday calendar. A week with a public holiday still counts that weekday in the weekday total. If your project plan needs holiday awareness, export the weekday count and subtract holidays yourself from an official list.

Swapped dates

If you type the later date in the start field, the calculator still reports a positive span and shows a note that the inputs were swapped. You get the same total days either way. That saves a silent negative count when someone pastes columns in the wrong order.

Try the dates yourself

Switch between difference, add, and subtract. Toggle exclude weekends on the difference tab and compare 90 calendar days between the dates with 65 weekdays counting both ends on the sample span.

Common planning uses: gap between invoice date and due date, days until a trip, or how far a “net 45” promise really stretches when you subtract from month-end. For each of those, decide first whether you need calendar days, weekdays, or a shifted result date. Then pick the matching tab instead of forcing everything through one mental shortcut. When in doubt, write both the day total and the result date on your note so nobody has to reverse-engineer your intent later. For calendar age instead of a day span, see how to calculate age from date of birth.