Free Date Difference Calculator Online

Find the exact number of days, weeks, months and business days between any two dates — with automatic leap year and weekend handling.

Enter two dates to calculate the difference
Please enter both a start and end date.
Your result will appear here

How This Calculator Works

01The difference is calculated using real calendar dates, so leap years, including February 29, are automatically included in every total.
02Turn on "Include end date" when counting inclusive spans, like the number of nights in a booking or days in an event that includes both the start and end day.
03Business days count Monday through Friday only; this tool doesn't exclude public holidays since holiday calendars vary widely by country.
04Use the swap button to instantly flip which date is the start and which is the end.
05Set the start date to today and the end date to any future date to get an instant countdown in days, weeks, and months.

Calculating someone's age or a birthday instead?

Features

✓Exact difference in years, months and days
✓Total days, weeks and months between dates
✓Business day and weekend day counts
✓Include-end-date toggle for inclusive spans
✓Automatic leap year handling
✓Works with past, present or future dates in either field
✓One-click date swap
✓Quick presets for common spans
✓No sign-up, no data stored
✓Fully responsive on any device

A Date Difference Calculator Built for Real Planning

Working out the gap between two dates comes up constantly — how many days until a deadline, how many business days a project has left, how long a lease or contract runs, or simply how much time has passed since something happened. ToolPlex's free date difference calculator handles all of these from a single pair of inputs, breaking the result down into years, months, and days, then adding total days, weeks, months, business days, and weekend days for a complete picture.

Because the tool accepts any combination of past, present, or future dates, it doubles as a countdown calculator: set the start date to today and the end date to a deadline, event, or milestone to see exactly how much time remains.

Calendar Days vs. Business Days

Calendar days count every single day in a range, including weekends, while business days count only Monday through Friday. This distinction matters for anything tied to work schedules — shipping estimates, project timelines, or notice periods often specify business days rather than calendar days, and the two can differ by several days over a longer span. This calculator shows both automatically so you don't need a separate lookup.

Inclusive vs. Exclusive Date Ranges

A common source of off-by-one errors is deciding whether to count both the start and end date. Booking a hotel from the 10th to the 13th is 3 nights, but describing "the 10th through the 13th" as a span of days is sometimes meant to include all 4 calendar days. The Include End Date toggle on this calculator lets you switch between these two common interpretations depending on what you're actually measuring.

Why Leap Years Complicate Manual Date Math

Any date range spanning multiple years risks running into a February 29, and manual day-counting or a rough 365-day-per-year estimate will drift by a day for every leap year crossed. This calculator works from actual calendar dates rather than day-count approximations, so leap years are handled correctly without any extra effort.

Common Uses for a Date Difference Calculator

People use date difference calculators to count down to deadlines and events, calculate the length of employment or a lease, work out delivery or notice periods in business days, measure the duration of a project or trip, and settle questions like "how long ago was that." Because this tool covers calendar days, business days, weeks, and months in one result, it handles nearly all of these without switching tools.

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Frequently Asked Questions