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Time to Decimal Calculator

Convert hours, minutes, and seconds to decimal hours and back.

Time arithmetic

Convert time and decimal hours

Result

Enter time values and choose Calculate.

Formula version 1.0.0 · Date and time-zone rules are excluded.

How to use this calculator

  1. Choose the conversion direction.
  2. Enter hours/minutes/seconds or decimal hours.
  3. Select Calculate.
  4. Review both normalized time and decimal hours.

Symbols and units

SymbolMeaningUnit or domain
decimal hoursTotal seconds divided by 3,600Hours
h:m:sNormalized time durationHours, minutes, seconds

Checked examples

Time to decimal

Inputs: 1 h 30 m 0 s

Calculation: 1 + 30/60

Result: 1.5 hours

Thirty minutes is half an hour.

Check: time-basics.test.ts — converts to decimal

Decimal to time

Inputs: 2.25 hours

Calculation: 2.25 × 3600 = 8100 seconds

Result: 2:15:00

A quarter hour is 15 minutes.

Check: time-basics.test.ts — converts from decimal

Assumptions, rounding, and limits

  • Conversion uses 60 minutes per hour and 60 seconds per minute.
  • Decimal-to-time rounds to the nearest whole second.
  • No payroll rounding rule is applied.
  • Negative decimal durations retain their sign.

Frequently asked questions

Is 1 hour 30 minutes 1.30 hours?

No. It is 1.5 hours because 30/60 = 0.5.

How are fractional seconds handled?

Decimal hours are rounded to the nearest whole second for the time display.

Is this payroll decimal time?

It is mathematical conversion only; employer rounding rules may differ.

Sources and review

Formula version
time.decimal@1.0.0
Formula review
Equatara formula review
Editorial review
Equatara editorial review
Last verified
2026-10-25
Applicability
Global clock arithmetic without dates, zones, payroll, or legal rules.
Next review
On material change or by 2028-10-25.

Found a problem?

Report a formula, result, example, source, or accessibility issue through the calculator correction process. Do not include sensitive input values.