# Time and Date Difference Calculator

> Calculate signed elapsed time between two dates and clock times.

Page: https://askcalculators.com/calculator/time-and-date-difference-calculator/
Definition: https://askcalculators.com/calculator/time-and-date-difference-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/time-and-date-difference-calculator/schema.json
Version: 1.0.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/calculator/time-and-date-difference-calculator/?startDate=2026-09-01&startTime=09%3A00&endDate=2026-09-03&endTime=17%3A30

## Inputs
- startDate: Start date; type=date; required; default=2026-09-01
- startTime: Start time; type=time; required; default=09:00
- endDate: End date; type=date; required; default=2026-09-03
- endTime: End time; type=time; required; default=17:30

## Outputs
- duration: Elapsed duration; format=text; primary
- totalDays: Total days; format=number
- totalHours: Total hours; format=number
- totalMinutes: Total minutes; format=number
- totalSeconds: Total seconds; format=integer

## Formula
elapsed milliseconds = end date-time − start date-time

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.