Tested tool guide
Tested browser tools
Checked August 16, 2026
What Expected Value / Decision Tree Calculator does, with a checked example
Enter each decision alternative, its chance branches, branch probabilities, and monetary outcomes. The calculator multiplies each terminal outcome by its path probability, rolls those weighted values up the tree, and compares alternatives by expected monetary value. Its sensitivity analysis tests how changes to an assumption can change that ranking. The common surprise is that EMV is not the payoff most likely to occur in a single decision; it is a probability-weighted average based on the entered scenarios.
Worked example
A concrete input and expected output from the current implementation.
Input
Decision: Launch
Success | probability 0.60 | outcome $50,000
Failure | probability 0.40 | outcome -$20,000
Decision: Hold
Certain | probability 1.00 | outcome $5,000
->
Expected output
Launch EMV: $22,000
Hold EMV: $5,000
Launch has an EMV of (0.60 x $50,000) + (0.40 x -$20,000) = $22,000. Hold has an EMV of 1.00 x $5,000 = $5,000, so Launch leads by $17,000 under these assumptions.