EVA · Expected Value Analyzer

EVA is a free, in-browser decision-tree tool. Build a tree of decision nodes and chance nodes, enter the probabilities and payoffs, and EVA instantly computes the expected value, the spread of outcomes (risk), and the optimal policy — the choices that maximize expected value by folding the tree back from its leaves.

What you can use it for

• Sizing and comparing bets and prediction-market positions by expected value.
• Business and product decisions under uncertainty.
• Teaching or learning expected value and decision analysis.

How it works

1. Add decision nodes (choices you control) and chance nodes (uncertain outcomes).
2. Enter a probability and a payoff for each outcome.
3. Read the expected value, risk, and highlighted optimal path — recomputed on every edit.
4. Save your tree and share a link; anyone can open an editable copy.

EVA runs entirely in your browser and requires no sign-up to start. Open EVA to build a decision tree →