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The PartyMutuel guides

Everything you need to run a racetrack in your living room — the math, the hosting craft, and the vocabulary — written for people whose entire betting experience is picking the horse with the funniest name.

Parimutuel scoring is a genuinely beautiful piece of 19th-century math: one shared pool, odds set by the crowd itself, and payouts that always balance to the point. It's also, we'd argue, the best party engine ever invented — it turns any contest with a winner into two hours of alliances, betrayals, and someone's aunt hitting a longshot. These guides teach the whole system from scratch. No prior betting knowledge is assumed, no real money is involved, and every worked example checks out on a napkin.

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About the app these guides orbit

PartyMutuel is a free web app that does the scorekeeping these guides describe: a host enters the field, guests join with a six-character code from their own phones, a live toteboard shows the odds shifting as picks come in, and the app runs all the payout math the instant results are entered. It works for horse races on TV, award shows, big games, bake-offs — any contest with a winner. There's nothing to install and no account required; the optional $5/year pass just removes ads.

A thirty-second taste of the math

Here's the entire engine in one example. Ten friends put a combined 200 points into a win pool, with 80 of those points on the favorite. The favorite wins, so the whole 200-point pool is shared by the people who staked that 80: every point returns 200 ÷ 80 = 2.50 points. Someone who staked 10 gets back 25 — their 10, plus 15 profit, which is why the board showed 3-to-2. If the 20-point longshot had won instead, each of its backers' points would have returned 200 ÷ 20 = 10. No bookmaker set those prices; the room did, just by choosing. That single division, repeated across pools, is everything the toteboard does — and once you've seen it, the rest of these guides are details and garnish.

Why we wrote these

Because the alternative was watching another generation of party hosts run "everyone throws a guess in a bowl" and call it a pool. Parimutuel scoring deserves better — it's fairer (the crowd sets every price), more dramatic (odds move live, in front of everyone), and self-balancing (the pot always pays out exactly what went in). The system has entertained racetrack crowds for a hundred and fifty years; it will survive your uncle's opinions about post positions. And if these pages teach you enough that the infield toteboard makes sense on your next real track visit — from the grandstand, julep in hand — that's a happy side effect. Until then, the guides below are short, self-contained, and ordered so each one builds on the last — read one before your next party, or work through the whole shelf with your coffee, and you'll be the person at the rail everyone else quietly asks what the numbers mean.

Open PartyMutuel and start a pool