Share
WhatsAppFacebookX (Twitter)TelegramLinkedInE-mail
EN
EnglishPortuguêsEspañolFrançais
← BackHome › Everyday › Probability Calculator

Probability Calculator

By the CalcMundi team · Updated October 22, 2026 · Formulas checked against standard financial math

Enter favorable and possible outcomes. Add the number of tries to see the chance of at least one success or exactly k successes.

Formulas

  • Probability = favorable ÷ possible outcomes.
  • At least once in n tries = 1 − (1 − p)n.
  • Exactly k in n = C(n, k) × pk × (1 − p)n − k.

Example

Rolling a 6 on a die is 1 in 6, or 16.67%. In 10 rolls, the chance of at least one 6 is 83.85%, and of exactly two 6s is 29.07%.

Lotteries

Matching all 5 white balls and the red ball in Powerball is 1 in 292,201,338. Enter 1 favorable and 292201338 possible outcomes to see it.

Frequently asked questions

After 5 heads, is tails more likely?

No. Each flip is independent: still 50%.

Odds vs. probability?

“1 in 4” is a probability of 25%. Odds of 1 to 3 mean the same thing.

See also

Gas Cost CalculatorFuel cost for your trip, split per personProportion CalculatorSolve A/B = C/X, direct or inverseSquare Footage CalculatorArea of rooms, floors and lotsPaint CalculatorGallons of paint for your room

Add this calculator to your website

Free for blogs, real estate agents, brokers and any site. Paste this code where you want the calculator to appear. It adjusts its height on its own.

Results are estimates for information only and are not financial, legal or medical advice. Rates, taxes and fees vary — confirm with a professional or your lender.