Time Duration Calculator – Hours Between Times & Converter
Calculate time durations free — hours between two times, add or subtract hours and minutes, convert to decimal hours. No signup, instant.
Tool Interface
Find the time between two times, add or subtract hours and minutes, and convert between hours and decimal — free, instant, no signup.
Overnight shifts are handled automatically — if the end time is earlier than the start time, it counts as the next day.
How to use
- Time between: enter a start and end time to get the duration in hours, minutes, and decimal hours.
- Add / subtract: add or remove hours and minutes from any time — handy for shifts and scheduling.
- Hours ⇄ decimal: convert 1:30 to 1.5 hours, or 2.75 back to 2:45.
- Overnight shifts work automatically — 22:00 to 06:00 gives 8 hours.
- Results update instantly and are free forever, no signup.
100% private — all calculations run in your browser.
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About This Tool
Introduction: What Is the Time Duration Calculator?
The Time Duration Calculator by Trencada answers the everyday question "how many hours is that?" in seconds. Find the duration between two times, add or subtract hours and minutes from any time, or convert between hours:minutes and decimal hours — perfect for work shifts, timesheets, billing, payroll, and scheduling.
Every calculation runs 100% in your browser, so your times never leave your device. Free, no signup, instant.
How to Use the Time Duration Calculator on Trencada.com
Choose a mode and calculate:
- Time between: Select the "Time between" tab, enter a Start time (default 9:00 AM) and End time (default 5:30 PM), then click "Calculate duration." You'll see the duration as hours and minutes, plus total minutes and decimal hours.
- Add / subtract: Select the "Add / subtract" tab, enter a Start time (default 2:00 PM), choose "Add (+)" or "Subtract (−)" from the Operation dropdown, enter Hours (0–999) and Minutes (0–59), then click "Calculate" to see the resulting time. If the result crosses midnight, you'll see "(next day)" or "(previous day)."
- Hours ⇄ decimal: Select the "Hours ⇄ decimal" tab, enter a value like "1:30" or "1.5," choose "Auto-detect," "Hours → decimal," or "Decimal → hours" from the Convert dropdown, then click "Convert."
Overnight shifts are handled automatically — if the end time is earlier than the start time, it counts as the next day. For example, 10:00 PM to 6:00 AM correctly gives 8 hours.
Key Features
Three Modes in One Tool
Switch between "Time between," "Add / subtract," and "Hours ⇄ decimal" using the tabs — no reloading or opening another page.
Overnight Shifts Handled Automatically
If the end time is earlier than the start time, it's counted as the next day. 10:00 PM to 6:00 AM gives 8 hours, with a note confirming the overnight calculation.
Multiple Result Formats
See durations as "X hours Y minutes," total minutes, and decimal hours (for example, 8 hours = 480 minutes = 8.00 decimal hours) — whatever format you need for timesheets or billing.
Day-Rollover Notes
When adding or subtracting crosses midnight, the result clearly notes "(next day)" or "(previous day)" so you always know which day the time falls on.
Flexible Add and Subtract
Add or subtract up to 999 hours and 59 minutes from any start time — ideal for calculating shift ends, project deadlines, and future appointments.
100% Private and Instant
All calculations happen locally in your browser using client-side JavaScript — no account, no signup, and no data sent to any server. It works on desktop and mobile with full dark-mode support.
Why Choose Trencada?
Trencada offers simple, reliable online tools for everyday calculations — from time and math to finance and health. Every tool on Trencada.com is free, works directly in your browser, and never requires installation or registration.
If you track work hours for pay, pair the Time Duration Calculator with our Salary to Hourly Converter to convert your salary to an hourly rate.
Frequently Asked Questions
Is the Time Duration Calculator free?
Yes — all Trencada tools are free with no signup and no hidden limits.
Does it handle overnight shifts?
Yes. If the end time is earlier than the start time, it is counted as the next day. For example, 10:00 PM to 6:00 AM gives 8 hours, with a note confirming the overnight calculation.
What are decimal hours?
Hours written as a decimal number — 1:30 is 1.5 hours, and 2.75 is 2:45. Decimal hours are commonly used for timesheets, payroll, and billing.
Do you store my inputs?
No. The Time Duration Calculator runs entirely in your browser using client-side JavaScript. No times, inputs, or personal data are sent to any server.
Can I add more than 24 hours?
Yes. In "Add / subtract" mode, you can add up to 999 hours. If the result crosses midnight, it will note "(next day)" or "(previous day)" so you know which day it falls on.
What does "Auto-detect" do in the Hours ⇄ decimal mode?
"Auto-detect" looks at your input: if it contains a colon (like 1:30), it converts Hours → decimal; if it's a plain number (like 1.5), it converts Decimal → hours. You can also force a specific direction with "Hours → decimal" or "Decimal → hours."