# Date to Date Calculator

URL: https://speedycalculator.com/calculators/everyday-life/date-to-date/
Last updated: 2026-10-25

> The date to date calculator measures the time from one date and time to another in years, months and days, and in total weeks, days, hours, minutes and seconds.

## Inputs

- Start date
- Start time
- End date
- End time

## Results

- Years
- and months
- and days
- Total days
- Total weeks
- Total hours
- Total minutes
- Total seconds

## Formula

```
Duration = (end date + end time) − (start date + start time)
Years, months, days = whole calendar years and months, then remaining days
```

## Explanation

Expressing a time span in several units at once helps with contracts, projects, ages and anniversaries. Hours and seconds include the clock times, so the count is exact to the minute.

### How to use the Date to Date Calculator

- **Start date**
- **Start time**
- **End date**
- **End time**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter the start date and time and the end date and time.

### Tips

- Check whether the end date should be included – event durations usually include it, elapsed time does not.
- Months have 28–31 days, so "one month" is counted by calendar date, not as 30 days.
- Use 24-hour time or set AM/PM carefully when entering clock times.
- Time zones and daylight-saving changes are not applied unless the calculator says so.

### Common mistakes to avoid

- Counting a 30-day month when a calendar month is meant (or the reverse).
- Forgetting leap years when counting days across February.
- Mixing decimal hours (7.5 h) with clock time (7:30).

### Inputs explained

FieldWhat to enterStart dateA dateStart timeA clock time (hours and minutes)End dateA dateEnd timeA clock time (hours and minutes)

### What each result means

- **Years** = sign([Months])×floor(abs([Months])÷12)
- **and months** = sign([Months])×mod(abs([Months]), 12)
- **and days** = [End date] - addmonths([Start date], [Months])
- **Total days** = [End date] - [Start date] + ([End time] - [Start time])÷24
- **Total weeks** = [Total days]÷7
- **Total hours** = [Total days]×24
- **Total minutes** = [Total days]×1440
- **Total seconds** = [Total days]×86400

## Worked example

Inputs — Start date: 2026-10-25; Start time: 00:00; End date: 2027-11-29; End time: 00:00.

Results — **Years = 1**; and months = 1; and days = 4; Total days = 400; Total weeks = 57.14; Total hours = 9,600; Total minutes = 576,000; Total seconds = 34,560,000.

## FAQ

**How many days from one date to another?**
Subtract the dates; the total days are shown, including any part day from the times.

**How many seconds are in a year?**
31,536,000 in a common year and 31,622,400 in a leap year.

**Why do months vary?**
Calendar months have 28–31 days, so "months and days" depends on the actual dates.

**What formula does the Date to Date Calculator use?**
Duration = (end date + end time) − (start date + start time).