How do I calculate days between two dates?

Subtract start from end in whole days. Optionally include the end date. We also show weeks+days and a calendar Y–M–D breakdown.

How are months added to month-end dates?

We clamp to the last valid day of the target month, e.g., Jan 31 + 1 month → Feb 28/29.

Do you handle time zones or daylight saving time?

We compute with date-only values anchored at local noon to avoid DST artifacts. For time-aware math, use a datetime tool.

Date Calculator: Days Between Dates or Add/Subtract Days Online

Q: What does weekdays-only mean?

The count includes Monday–Friday only. Holidays are not excluded.

Date Calculator

Figure out exact day counts, add or subtract days, and pinpoint target dates with weekends and holidays in mind. This is handy for planning deadlines, travel itineraries, billing cycles, academic due dates, or any timeline where leap years and business days can change the math.

The Date Calculator lets you compute durations between two dates, project a future (or past) date from a chosen start, and optionally focus on working days only. The goal is clear scheduling-no more hand-counting or misreading calendars-so you can set realistic timelines, coordinate with teams, and lock in milestones confidently. Enter your details below to get a precise result in seconds.

How this calculator works

Differences are computed from whole calendar days between dates. The calendar breakdown borrows days and months when needed, mirroring how people express durations.

Show math & assumptions

Let A and B be dates at local noon to avoid DST issues; reorder so A ≤ B.
Total days: Δ = ⌊(B − A)/86400000⌋ (+1 if inclusive).
Weeks: ⌊Δ/7⌋, remainder: Δ mod 7.
Weekdays: full weeks × 5 + weekdays in the remainder starting from A.
Add/subtract months/years: clamp to last day of target month if needed.

FAQ

Do you include the end date?

Toggle “Include end date” to count it. Many deadline calculations are inclusive.

What does “weekdays only” mean?

We count Monday–Friday. Federal or local holidays are not excluded.

Why don’t you count hours/minutes?

This is a date-only tool. For time-of-day precision, use a datetime calculator.

How do you handle month lengths when adding months?

We clamp to the last valid day-e.g., Jan 31 + 1 month → Feb 29 (leap year) or Feb 28 (non-leap).

Can I subtract business days?

Use “Skip weekends” with unit = days, then choose Subtract.

Why do other sites show a different total?

They may count inclusively by default, use time-of-day, or a different weekend/holiday policy.

What our Date Calculator does

Our date calculator tool answers two core questions fast: How many days are between two dates? and What date is a certain number of days, weeks, months, or years from a starting point? This page is built for clarity and speed-pick your mode, enter dates and options, and see both a step-by-step explanation and a clean final answer.

Finding the difference between two dates

Use the Between dates mode to measure a span. We compute the exact number of calendar days, optional inclusive counting, an easy weeks+days breakdown, and a calendar-accurate years–months–days view. Choose Weekdays only to ignore Saturdays and Sundays-useful for workback schedules and delivery SLAs.

Adding or subtracting time

Switch to Add / Subtract to project forward or backward. Days and weeks use straight calendar arithmetic, while months and years clamp safely to the last day of the target month to avoid invalid dates. For day-level work calendars, toggle Skip weekends (for “days” only) to walk past Saturdays and Sundays automatically.

Why inclusive counting matters

Legal and academic contexts often include the end date. For example, a “90-day inclusive” window starting May 1 ends on July 29, not July 30. Use the checkbox to match your policy and avoid off-by-one mistakes.

Common pitfalls

Assuming all months have 30 days-harmful when adding months from month-end dates.
Forgetting to specify inclusive/exclusive rules on deadlines.
Mixing in time-of-day or time zones for a date-only calculation and creating DST artifacts.

Limitations

This tool works with dates, not times, and does not exclude holidays. If you need holiday calendars or time-zone aware math, use a specialized scheduling system.

Practical examples

Example 1: Start 2025-01-15, add 2 months → 2025-03-15. From Jan 31, adding one month clamps to Feb 28/29 depending on leap year.

Example 2: Between 2025-06-01 and 2025-06-30 inclusive → 30 days; exclusive → 29 days.

Example 3: Base 2025-08-01, add 10 weekdays → skips two weekends to land on a Monday.

Date Calculator

Your dates

Final result

Date Results interpretation