How is the difference calculated?

The tool uses the exact date and time you enter and shows total days, hours, minutes, and seconds between them.

Online Time and Date Difference Calculator

Calculate the difference between two dates and times in days, hours, minutes, and seconds.

Start date & time

End date & time

How is the difference calculated?: The tool uses the exact date and time you enter and shows total days, hours, minutes, and seconds between them.

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.