Add or subtract a duration (hours and minutes) from a start time, or add/subtract two durations.

Enter time as HH:MM (24-hour) or as separate hours and minutes.

Does it wrap past midnight?

Yes. Results can be on the next or previous day; the tool shows the time and optionally the day change.

Online Time Calculator

Add or subtract time (hours and minutes) in a simple way.

Start time

Duration (hours : minutes)

What can I do?: Add or subtract a duration (hours and minutes) from a start time, or add/subtract two durations.
What time format?: Enter time as HH:MM (24-hour) or as separate hours and minutes.
Does it wrap past midnight?: Yes. Results can be on the next or previous day; the tool shows the time and optionally the day change.

Celsius to Fahrenheit Converter

Convert Celsius to Fahrenheit and Fahrenheit to Celsius instantly. Free temperature converter.

Tip Calculator

Calculate tip and split the bill. Enter bill amount, tip percentage, and number of people.

Roman Numeral Converter

Convert numbers to Roman numerals and Roman numerals to numbers. Supports 1–3999.

Combinations Calculator

Calculate C(n,r) — the number of ways to choose r items from n without order. Uses n!/(r!(n-r)!).

Combinations with Replacement Calculator

Calculate the number of ways to choose r items from n with repetition allowed. Formula: C(n+r-1, r).

Even Permutations Calculator

Count how many permutations of n objects are even (expressible as an even number of swaps). For n ≥ 2, equals n!/2.