Date Difference Calculator

This calculator answers a deceptively simple question: how many days are there between two dates? It gives you two practical views. The default returns calendar days, which include every day on the calendar. Turn on weekdays only to switch to business days, which count Monday through Friday and skip weekends automatically. If you paste holiday dates using the YYYY-MM-DD format, those days are excluded from the business-day total as well, so the number reflects working time more closely.

The Include end date toggle controls whether the range is inclusive or exclusive. Inclusive counts both boundary dates; exclusive stops one day before the end. Schedules, countdowns, and legal wording often rely on this detail, so the setting is explicit and easy to flip. The tool also provides two compact summaries to help you sanity-check results at a glance: a weeks + days view (useful in project timelines and travel planning) and a calendar-accurate years–months–days breakdown. Because we work with whole local days, daylight saving jumps don’t change totals.

Typical uses include planning a vacation window, estimating working time for a ticket queue or an SLA, and figuring out milestones such as due dates, anniversaries, and renewal periods. Calendar days are great for countdowns and reminders. Business days make more sense when resources generally operate Monday–Friday. If your organization observes specific holidays, paste them into the field and the calculator will subtract them from the business-day tally automatically. You can save or share a link with query parameters so the exact configuration reproduces later without extra clicks.

• Start and End accept any valid date. The Swap button flips them if you entered them in reverse.
• Holidays accept comma-separated ISO dates like 2025-01-01. Only dates inside the range affect the count.
• Weeks + days divides the calendar-day total by seven for a fast mental model.

Reading the result is straightforward. The headline tells you the main count in plain language. The subline shows the exact range, whether it’s inclusive or exclusive, and whether holidays were removed. A short key-value block lists calendar days, the weeks-plus-days view, and the calendar breakdown into years, months, and days. If the calculator detects that the start date is after the end date, it gracefully swaps them, labels that fact, and still gives you correct numbers. Results are locale-formatted so large counts remain easy to scan.

For planning, treat this as a simple, dependable building block. Add the number to a cost estimate, use it to size a sprint, or share it with a client to align on timelines. If you work across regions, double-check the holiday list and make sure the inclusive/exclusive choice matches the contract wording. For long spans, rely on the years–months–days line: it accounts for leap years and different month lengths, so a “30-day month” assumption will not creep in.

Limits are intentional. The calculator does not apply time-of-day cutoffs, partial days, or custom workweeks beyond Monday–Friday. If you need those, export the headline number and refine it in your own spreadsheet or scheduling software. For event planning, you might use calendar days to drive reminders and business days to plan staffing. Keep both counts in view and you’ll avoid mismatches between public dates and behind-the-scenes work time.

Small habit, big payoff: before you commit a timeline, run the range with and without the end date, and print the business-day version with holidays excluded. Those three checks catch most off-by-one errors and “forgot the long weekend” surprises.

We compute the total number of whole days between the two dates, then add one if the Include end date option is selected. For business days, we remove Saturdays and Sundays in constant time using full-week blocks plus the remainder days, then subtract any listed holidays that fall on weekdays within the range. The years–months–days line is a real calendar difference: we roll forward by years, then months, then count leftover days so leap years and month lengths are respected.