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SnapCalculations

Probability Calculator

Find the chance of an event, combine two independent events, or work out how likely something is to happen at least once over several tries.

Type of question

Probability

16.6667%

1/6 as a fraction

Decimal
0.16666667
Odds in favour
1 : 5
Chance it doesn't happen
83.3333%
About 1 in
6

Step-by-step solution

Worked out with your numbers. Change any value above and the steps update.

  1. 1

    Probability = favourable outcomes ÷ total outcomes

    1 ÷ 6 = 1/6

  2. 2

    As a decimal

    1 ÷ 6 = 0.16666667

  3. 3

    Probability it doesn't happen: 1 − P

    1 − 0.16666667 = 0.83333333

  4. 4

    As a percentage

    0.16666667 × 100 = 16.6667%

How it works

  • One event: probability = favourable outcomes ÷ total outcomes. Rolling a 6 on a die is 1/6.
  • Two independent events: P(A and B) = P(A) × P(B), and P(A or B) = P(A) + P(B) − P(A and B).
  • Repeated tries: P(at least once) = 1 − (1 − p)ⁿ, where p is the chance per try and n the number of tries.
  • Odds in favour compare favourable to unfavourable outcomes: 1 in 6 is odds of 1 : 5.

Frequently asked questions

What are independent events?

Events where one doesn't change the chance of the other, like two coin flips. Drawing cards without putting them back is not independent.

If something has a 1 in 6 chance, will it happen in 6 tries?

Not for certain. The chance of at least one success in 6 tries is about 66.5%. Use the repeated tries option to check any number of tries.

Results are estimates for general information and are not financial, medical or professional advice.