Time Calculator | TheSmartCalculator - Free Online Calculators

Operation

Time 1

Hours

Minutes

Seconds

Time 2

Hours

Minutes

Seconds

About the Time Calculator

Time arithmetic is surprisingly tricky — adding 1 hour 45 minutes to 2 hours 30 minutes isn't as straightforward as adding regular numbers because 60 minutes equals 1 hour, not 10. Our Time Calculator handles all of this automatically, making it easy to add or subtract time durations, convert between time units, and calculate elapsed time between two moments.

It's the tool for video editors tracking clip lengths, project managers summing task durations, educators timing activities, and anyone who needs to work with hours and minutes accurately.

How It Works

Choose your operation: add/subtract time durations, or calculate elapsed time between two specific timestamps. Enter your values in hours, minutes, and seconds. The calculator performs the arithmetic with proper borrowing and carrying across time units and displays the result in multiple formats.

Formula / Key Reference

Time addition: Convert everything to seconds, add, convert back

Total seconds = (Hours × 3600) + (Minutes × 60) + Seconds

Result Hours = Total Seconds ÷ 3600 (integer part)

Result Minutes = (Total Seconds mod 3600) ÷ 60

Result Seconds = Total Seconds mod 60

Real-World Example

Video editing scenario:

Clip 1: 0h 12m 43s

Clip 2: 0h 07m 28s

Clip 3: 0h 22m 05s

Intro/outro: 0h 02m 30s

Total = 12m43s + 7m28s + 22m05s + 2m30s

Converting to seconds:

Clip 1: 763s

Clip 2: 448s

Clip 3: 1,325s

Intro: 150s

Total: 2,686 seconds

2,686 ÷ 3600 = 0h remainder 2,686

2,686 ÷ 60 = 44m remainder 46s

Total runtime: 44 minutes and 46 seconds

This exactly matches YouTube's expected video length for a 45-minute educational video — making time calculation critical for content creators planning upload segments.

Common Uses

Adding up task or project durations in project management

Video and audio editing: total runtime, segment timing

Timesheet calculations: summing work sessions with breaks

Sports: summing lap times, segment times, or competition durations

Recipe timing: staggering cooking tasks to finish simultaneously

Frequently Asked Questions

Why is time arithmetic different from regular math? ▼

Regular numbers use base-10 (10 ones make 1 ten). Time uses mixed bases: 60 seconds make 1 minute, 60 minutes make 1 hour, 24 hours make 1 day. Adding 50 minutes + 25 minutes = 75 minutes = 1 hour 15 minutes requires carrying at 60, not 10. This is why time calculation errors are so common when done manually.

How do I add times that span midnight? ▼

If you're adding time durations (e.g., 14 hours + 12 hours = 26 hours), the result is just a number of hours. If you're computing elapsed time between two clock times that span midnight (e.g., 10 PM to 6 AM), the calculator correctly adds 24 hours when the end time is earlier than the start time.

How do I convert hours to decimal for payroll? ▼

Divide the minutes by 60 and add to the hours. 6 hours 45 minutes = 6 + (45÷60) = 6.75 decimal hours. Alternatively, use our Hours Calculator, which performs this conversion automatically for payroll purposes. Payroll systems almost universally use decimal hours.