π² Probability Calculator
Probability is simply the count of ways something can happen divided by the count of everything that can happen. Enter your favorable and total outcomes and you get the chance as a percent, a decimal and classic β3 to 7β odds.
For two independent events β like two coin flips β multiply the chances for βboth happenβ, or add them and subtract the overlap for βat least one happensβ. The calculator does both in one step.
How to use this calculator
Choose single event or two independent events. Fill in the numbers for your case and press Calculate for the probability as a percent.
- Pick the Calculation mode: Single event or Two independent events.
- For a single event, type the favorable outcomes and the total outcomes.
- For two events, type P(A) and P(B) as decimals between 0 and 1.
- Press Calculate and read the probability, shown as a percent with a plain decimal beside it.
Frequently asked questions
What does this probability calculator compute?
In single-event mode it divides favorable outcomes by total outcomes, giving the chance as a percent, a decimal and classic odds like 3 to 7. In two-event mode it computes P(A and B) as the product and P(A or B) as the sum minus the overlap.
Can you show a worked example?
Drawing an ace from a deck: 4 favorable out of 52 total gives 7.69 percent. Two coin flips both landing heads: 0.5 times 0.5 gives a 25 percent chance of both, and a 75 percent chance of at least one head.
What does independent mean here?
Independent means one event does not change the other's chances, like two separate dice rolls. If the events influence each other, for example drawing cards without replacement, the simple product rule does not apply.
How do I read the odds output?
Odds of 3 to 7 mean 3 favorable outcomes against 7 unfavorable ones out of 10 total. To turn odds back into a probability, divide the first number by the sum of both.