Pari-Mutuel Pool Calculator
Calculate exact pari-mutuel payoffs based on pool size, takeout rate, and winning bet distribution. Understand how horse racing odds are determined.
Formula:Payoff = (Net Pool ÷ Winning Bets) × Your Bet
Pool Analysis
Your $2 Bet Pays
$21
Profit: $19
Pool Breakdown
Net Pool: $85,000 | Takeout: $15,000
Bet on winner: 8.0% of pool
Decimal Odds
10.63
Implied Prob
8.0%
Calculation Details
Total Pool$100,000
Takeout (15%)-$15,000
Net Pool$85,000
Winning Bets$8,000
Exact Payoff$21
Breakage-$0
Actual Payoff$21
$
Total amount wagered on this bet type
$
Total wagered on the winning selection
%
Track commission percentage
$
How much you bet on the winner
Pari-Mutuel Formula
1. Track takes commission: Net Pool = Total × (1 - Takeout)
2. Calculate per-dollar payoff: Rate = Net Pool ÷ Winning Bets
3. Your payoff: Payoff = Rate × Your Bet
4. Apply breakage: Final = Round Down to Dime/Nickel
Quick Answer
Pari-mutuel betting pools all wagers together. The track takes its cut (takeout), then divides the rest among winners proportionally. Your payoff depends on how much others bet, not fixed odds. This is why odds change until post time.
Key Concepts
Pool-Based Odds
Unlike fixed-odds betting, pari-mutuel odds are determined by the betting public. Heavy betting on one horse lowers its payoff; overlooked horses pay more.
The Takeout
Before any payoffs, the track removes 15-25% for operations, purses, and taxes. This is the "house edge" in pari-mutuel betting.
Frequently Asked Questions
How are pari-mutuel payoffs calculated?
The track takes its commission (takeout) from the total pool first. The remaining money is divided among winning ticket holders. If the pool is $100,000 with 15% takeout, $85,000 is available for winners.
What is the track takeout?
Takeout is the track's commission, typically 15-25% depending on bet type and jurisdiction. Win/Place/Show usually have lower takeout (14-18%) than exotics (20-25%). This is taken before calculating payoffs.
Why does the same odds pay differently at different tracks?
Pool size and takeout rates vary by track. Larger pools offer more stable odds, while smaller pools can shift dramatically. Different states also have different takeout regulations.
What is the minimum payout?
Most tracks guarantee a minimum $2.10-$2.20 payout per $2 bet ("minus pool"). When favorites are heavily bet, the track sometimes pays more than the pool mathematically allows.
Win Bets
Exotic Bets
Longshots
Favorites
How this works
Calculations follow the published mathematics of the game — combinatorics for cards, probability theory for dice, and expected-value accounting for wagers. Results are verified against independent references (primarily Wizard of Odds). No calculation here is an opinion or recommendation; it is arithmetic applied to the rules of the game.
What this tool can’t do
When to consult a professional
This tool computes probability and expected value. It is not a betting system and cannot predict the outcome of any individual wager. If gambling is causing problems for you or someone you know, call the National Problem Gambling Helpline at 1-800-GAMBLER.
Sources
- [1]Wizard of Odds — Michael Shackleford, ASAIndustrywizardofodds.comAccessed Apr 21, 2026
Actuary; widely cited casino-game probability reference. Used for house-edge and EV verification.
- [2]National Council on Problem GamblingOfficial sourcencpgambling.orgAccessed Apr 21, 2026
Responsible-gambling guidance and 1-800-GAMBLER helpline.
Joseph OrdunaFounder & Software Engineer
Full-stack software engineer specializing in embedded systems, web architecture, and AI/ML. Founder of Practical Web Tools. Built the gesture-controlled drone IP acquired by KD Interactive (Aura Drone, sold on Amazon).
Pool Analysis
Your $2 Bet Pays
$21
Profit: $19
Pool Breakdown
Net Pool: $85,000 | Takeout: $15,000
Bet on winner: 8.0% of pool
Decimal Odds
10.63
Implied Prob
8.0%
Calculation Details
Total Pool$100,000
Takeout (15%)-$15,000
Net Pool$85,000
Winning Bets$8,000
Exact Payoff$21
Breakage-$0
Actual Payoff$21