Time conversion calculators

How to choose and check a conversion

Elapsed time uses fixed relationships such as 60 seconds per minute and 60 minutes per hour. Decimal hours are a numeric quantity: 1.5 hours equals 1 hour 30 minutes. They should not be confused with a clock entry written as hours and minutes.

Calendar periods are not fixed in the same way. Months contain different numbers of days, years may be leap years, and civil times can change with time-zone and daylight-saving rules. Use date-aware tools for calendar scheduling.

Payroll and billing systems often define their own rounding increments. Calculate from the original minutes first, then apply the required organizational rule. Rounding each segment separately can produce a different total from rounding once at the end.

Accuracy and sources

Convertly keeps additional precision during calculation and rounds the display for readability. Match the final precision to the source measurement and the purpose of the answer. See our methodology and source policy for definitions, primary references, limitations, and correction procedures.

Exact definitions, estimates, and rounding

Some unit relationships are exact definitions, while a measured input is still limited by the instrument used to obtain it. A calculator can correctly apply an exact factor without making the original measurement more precise. Keep the original unrounded value, perform the conversion, and round the final result to a level appropriate for the task.

Use the stated formula to check the direction of the conversion. When possible, test a familiar value such as 1, 10, or 100 before relying on an unfamiliar result. For professional, regulated, health, safety, or contractual work, confirm the required convention and rounding rule in the controlling standard or document.