Factorial: Your Questions Answered
These are the questions people ask most often about factorial. Each answer is short; follow the links for the full detail.
What does a factorial calculation tell me?
Calculates n factorial up to 170.
What is the formula?
n! = 1 × 2 × … × n.
What do I need to enter?
n.
Can I use any units?
Yes, as long as every input uses the same unit. The answer will be in that unit (squared for areas, cubed for volumes).
Can you show an example?
For example, with these inputs:
- n: 10
the calculator returns:
- n!: 3,628,800
Any tips?
- Check your answer by working backwards from the result.
- Keep units consistent: convert everything to the same unit before calculating.
- Round only at the final step to avoid accumulated rounding errors.
Background
A quick mental estimate before calculating is a powerful check. If a room's floor area comes out at 4,000 square metres or a percentage comes out above 100% when it should not, you know to look again.
Rounding is a common source of small errors. Keep full precision during intermediate steps and round only the final answer to the number of decimal places or significant figures the question asks for.
Calculators are best used to check working rather than replace it, especially for exams where method marks count. Work the problem by hand first, then confirm with the calculator.
Related calculations
- Fraction Simplifier: Reduces a fraction to its lowest terms.
- Ratio Simplifier: Simplifies a ratio.
- Decimal to Fraction Converter: Converts a decimal to a fraction.
- Scientific Notation Converter: Writes a number in scientific notation.
Try it yourself with the Factorial Calculator.
Run your own numbers: Factorial Calculator