What formulas are used?

Volume = (4/3)πr³; surface area = 4πr².

Use any consistent units. Volume in cubic units, surface area in square units.

Online Sphere Calculator

Calculate volume and surface area of a sphere from radius. Volume = (4/3)πr³, surface = 4πr².

Radius

What formulas are used?: Volume = (4/3)πr³; surface area = 4πr².
What units?: Use any consistent units. Volume in cubic units, surface area in square units.

Celsius to Fahrenheit Converter

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

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

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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.