EV Calculator

Expected value is the single number behind every good trading decision. Enter your own estimated win probability and the returns on offer to see whether the position pays over the long run — before you know how this one turns out.

Your win probability (%)

Returns offered (decimal)

Allocation ($)

+$10.00

Expected value

+10.00%

EV per allocation

+5.00 pts

Your edge

1.82

Fair returns

Positive EV — your probability beats the price. This is a value position.

Yoseri only computes the EV — it never places positions and is not a broker. You decide and place every position yourself, manually, at the broker of your choice.

Stop recalculating by hand

Track this automatically on your real positions

This runs one number, once. Yoseri applies the same math to every position you take — sizing, CLV and ROI computed for you, live on your dashboard. Free to start, no card.

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HOW IT WORKS

The method.

What it does

EV per $1 staked = your probability × decimal returns − 1. Multiply by your allocation for the money figure. Positive means the position pays on average; negative means it costs you, however good a single result might look.

Edge is where EV comes from

Your edge is your probability minus the returns' implied probability (1 ÷ decimal returns). Value exists only when your number is higher — without an edge, the EV is negative and the calculator says so.

Why +EV can still lose

EV is a long-run average, not a promise about the next position. A +EV position loses plenty of individual times — that's variance. Judge the decision by its EV, not by the last result, and repeat it across hundreds of positions.

The formula

EV% = (p × D − 1) × 100

Where

p— your true win probability
D— decimal returns
EV%— expected return per unit allocated

Per unit: EV = p × (D − 1) − (1 − p). Positive EV is the whole game; everything else is sizing.

Worked example

You estimate a 55% chance at returns of 2.00.

1.EV% = (0.55 × 2.00 − 1) × 100
2.EV% = (1.10 − 1) × 100

Result: +10% expected value per unit

Pro pitfalls

EV is only as good as your p — the market's implied probability is often closer to truth.
Positive EV still loses often; edge shows up over large samples, not single positions.
A big EV% on a long shot hides big variance — size it with Kelly, not conviction.

Educational only — not trading advice. Calculators and simulations are illustrative; past results and simulated outcomes don’t guarantee future returns. Position responsibly.

Related calculators

Kelly Calculator

CLV Calculator

Returns Converter

FAQ

Questions, answered.

EV is the average result of a position if you could repeat it many times. EV per $1 = your win probability × decimal returns − 1. Positive EV means the position pays over the long run; negative EV means it costs you on average, however a single result turns out.

That's the hard part — and the whole game. Build it from a model, market consensus (devigged closing returns), or your own research, then compare it to the price. The calculator turns your estimate into EV; the quality of the estimate is on you.

Your edge is your probability minus the returns' implied probability (1 ÷ decimal returns), in percentage points. EV is what that edge is worth in money at a given allocation. No edge, no positive EV — they're two views of the same thing.