Expected Value

Weigh a decision by what each outcome pays and how likely it is. Everything runs in your browser — nothing is sent anywhere.

Outcomes

Outcome Chance % Payoff

Payoffs are net — what you end up with, after what it costs you. A losing outcome is negative.

What do I need?

For solve its so the expected value is
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Result

Expected value —
Chance of profit
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Std deviation
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Best case
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Worst case
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Where the probability sits

Each block is one outcome, sized by how likely it is.

How it plays out

Starting with
Simulate runs of attempts each, drawn — and simulations for the stats

Click the chart or press 1 to keep re-rolling about 30 times a second — Esc or click again to stop. Hold R for a momentary burst.

Hover the chart to read a point.
24 simulated runs average of those runs expected value × attempts went bust — run ends

One expected value, many different stories. The dashed line is the theory; the runs are what actually happening feels like — which is the point of knowing the spread as well as the average. Raise the attempts and the runs converge on the dashed line; that convergence is what expected value means.