Probability Calculator
Calculate probability for coin tosses, dice rolls, card draws and normal distributions. Get combinations, permutations and z-scores.
Exact probability
24.6094%
Cumulative (≤ k)
62.3047%
Probability Calculator on True Calculator gives you an instant, accurate answer with no sign-up and no app install. Calculate probability for coin tosses, dice rolls, card draws and normal distributions. Get combinations, permutations and z-scores. Every result shows the formula and a worked example so you can verify the calculation yourself, and all values are computed in your own browser — your numbers never leave your device.
Popular uses: probability calculator · coin flip probability · dice probability calculator
Last updated: August 2026
How We Calculate
This calculator uses standard mathematical formulas verified by our team. All calculations are performed instantly in your browser using JavaScript — no data is sent to any server. The formulas used are industry-standard and match those used by banks, financial institutions and health organizations.
For financial calculators, we use RBI-approved formulas and regularly updated bank rates. For health calculators, we use WHO-recommended formulas and medical standards. All rates and standards are sourced from official government and regulatory websites.
Frequently Asked Questions
What is probability?
Probability is the likelihood of an event occurring, expressed as a number between 0 and 1. A probability of 0.5 means a 50% chance.
What is the difference between combinations and permutations?
Combinations (nCr) count groups where order doesn't matter. Permutations (nPr) count arrangements where order matters.
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