Tools and calculators

Prediction market calculators for the decisions traders actually make

Start with the question you need answered right now: how much tax to set aside, what a trade really costs, whether the edge is positive, how large the position should be, or whether an arbitrage spread still pays after real execution costs.

Start fast

Each tool answers the main question first, then lets you work the numbers without reading through filler before you begin.

Use real inputs

Model the trade you can actually place: fees, slippage, bankroll rules, withholding, and contract wording.

Keep context

Every page links to the supporting guides you may need for platform rules, trade setup, and next steps.

Tax and complianceUpdated March 8, 2026

Prediction Market Tax Calculator

Estimate how much federal and state tax you may need to set aside after prediction market winnings and losses.

Best for

US traders planning for filing season

Primary output

Estimated added tax and balance due

Use before

Large withdrawals or year-end position changes

This page answers

How much tax might I owe on prediction market winnings?

Models incremental federal tax instead of only total winnings
Accounts for standard deduction versus itemized deduction tradeoff
Includes withholding and simple state-rate planning

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All tools

Use the collection below to choose the calculator that matches the decision you need to make right now.

Execution and fees

Prediction Market Fee Calculator

See what a prediction market trade really costs after entry fees, exit fees, transfer costs, and other execution friction.

Combines platform, transfer, and flat execution costsSupports round-trip, settlement-win, and settlement-loss scenarios

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Trade selection

Expected Value Calculator

Check whether your probability edge still leaves a prediction market trade profitable after fees and slippage.

Turns your probability estimate into dollar EV and EV percentShows breakeven probability after friction

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Risk management

Kelly Position Size Calculator

Turn your edge and bankroll into a stake size you can actually use with Kelly and fractional Kelly sizing.

Computes full Kelly, adjusted Kelly, and capped sizeDesigned around binary contracts that settle at $1.00

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Resolution and rules

Prediction Market Resolution Checklist

Check wording, timing, and settlement rules before you trust a prediction market or hedge.

Flags blockers before executionUseful for both single-venue and cross-venue trades

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Arbitrage and execution

Arbitrage Profit Calculator

Check whether a prediction market arbitrage spread still leaves real profit after fees, slippage, and fixed costs.

Converts headline spread into net edge after frictionEstimates maximum matched size under a bankroll constraint

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Execution quality

Slippage Impact Calculator

See how fill quality changes your real PnL before you commit size to a prediction market trade.

Measures quoted PnL against executable PnLShows how much edge survives after slippage

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Pricing and probability

Break-Even Probability Calculator

Find the minimum win probability a trade needs after fees, slippage, and fixed execution costs.

Turns price and costs into a real win-rate thresholdShows the gap between market probability and required probability

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Process and review

Trade Journal Template Generator

Build a journal template that matches your trade type, review style, and the fields you actually maintain.

Builds both markdown and CSV-friendly journal structuresAdapts to directional, arbitrage, event-driven, and hedge workflows

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Odds and pricing

Odds Converter

Convert a quote into implied probability, prediction price, decimal odds, American odds, and fractional odds.

Converts between prediction price and standard betting formatsShows profit and return for a chosen stake

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