PolyTerminal
How to use it
Type a share price in cents, or decimal odds, American odds or a fraction like 7/13, in the first four boxes. Whatever you type, the other three follow. Below, enter the amount you want to spend, pick the category of the market for the taker fee (or no fee for a maker order), and say how the fee is counted. The result on the right shows what you win and what you lose, the shares you get, the fee and the break-even probability, with a short sentence that reads the numbers back in plain words.
A price is a probability
A winning share is redeemable for $1.00 and a losing share is worth $0.00. Polymarket is peer-to-peer: you trade with other users, not against a house. A share that trades at 65 cents therefore says the market puts the chance of that outcome at about 65 percent. Fees and the spread between buy and sell prices still take their share.
To read the same price as odds you only need three formulas. With the price written as a number p between 0 and 1:
- Decimal odds are 1 divided by p. They show what one dollar staked returns in total, including the stake.
- American odds are minus 100 times p divided by one minus p when p is at least one half, and plus 100 times one minus p divided by p when p is below one half.
- Fractional odds are the profit over the stake, (1 - p) divided by p, written as a fraction.
| Share price | Probability | Decimal odds | American odds | Fractional odds |
|---|---|---|---|---|
| 10 cents | 10% | 10.000 | +900 | 9/1 |
| 25 cents | 25% | 4.000 | +300 | 3/1 |
| 50 cents | 50% | 2.000 | -100 | 1/1 |
| 65 cents | 65% | 1.538 | -186 | 7/13 |
| 80 cents | 80% | 1.250 | -400 | 1/4 |
The price an interface displays is the midpoint of the bid-ask spread, with the last traded price shown instead when the spread is wide, and a buyer pays the ask. For a real order, enter the price you would actually pay, not the displayed one.
From price to payout
If you spend an amount and want to know what you get, the converter solves for the number of shares. It counts the fee in one of two ways. The converter starts with the fee added on top of the amount, which is how Polymarket describes a market buy in its developer documentation: the amount is the pre-fee USD notional, and the fee is charged on top. The amount buys the amount divided by the price in shares, and the fee comes extra. The other choice treats the amount as everything you spend, which matches an all-in spending limit: the fee sits inside the amount, so the shares are the amount divided by the price plus the fee per share.
A winning share is redeemable for $1.00, so the payout if you win is the number of shares, and your profit is the payout minus what you spent. If you lose, you lose what you spent.
The fee changes the break-even
A taker fee raises the true cost of a share, so the probability you need is higher than the price. The guide to Polymarket fees explains where the rates come from. The fee formula and the rates by category are on the fee calculator page. Pick a category in this converter and the break-even probability includes the fee for that category. Choose "No fee" to model a maker order.
For a share at 65 cents in a crypto market, for example, the probability you need is 66.59% instead of 65 percent.
What the converter does not do
- It does not say whether a price is too high or too low. That is your view of the real chance of the outcome against the price.
- It does not include the tiered Taker Rebate Program or any tax that applies to you.
- It does not include a builder fee. Orders placed through PolyTerminal carry PolyTerminal's Polymarket builder code, and PolyTerminal may charge a builder fee on top of Polymarket's own fees.
- It assumes you hold to resolution. If you sell earlier, the result depends on the price at which you sell.
FAQ
How do I convert a Polymarket price to a probability?
Read the price in cents as a percentage. A share at 65 cents implies a 65 percent chance, and the opposite side, the No share, trades near 35 cents. The two prices add up to about 1 dollar, with small differences caused by the spread.
What are decimal odds on Polymarket?
Decimal odds are 1 divided by the share price. At 65 cents they are about 1.54, which means a dollar spent returns about 1.54 dollars if the share wins, including the dollar you spent. At 25 cents they are 4.
How do I turn American odds into a Polymarket price?
Type them into the American odds box and read the price. For positive odds the price is 100 divided by the odds plus 100, so +300 is 25 cents. For negative odds, drop the minus sign: the price is that number divided by itself plus 100, so -186 is about 65 cents. Odds between -100 and +100 do not exist, except +100 and -100, which are the same even money as 50 cents.
Does the converter include the fee?
Yes, if you choose a category. With the fee added on top, the shares cost the amount you typed and the fee comes extra, so the loss if the share loses is the amount plus the fee. With the fee inside the amount, the loss is exactly the amount and you get fewer shares. With no fee set, it models an order that pays no fee, such as a maker order.
Do you store the amounts I enter?
No. The converter runs in your browser, nothing is sent to a server and nothing is stored. Once you change a value, the values are written into the part of the address after the # sign, so you can copy a link to your calculation. Browsers do not send that part to a website. If you share the link, whoever opens it sees your numbers.
Sources and checks
Every rule quoted in this article comes from the registry below. Each row names the official page and the day it was compared with the text.
All 19 rules used in this article
| Rule | Value | Official source | Checked |
|---|---|---|---|
| Redemption value of a winning share | $1.00 | docs.polymarket.com/ | |
| Value of a losing share | $0.00 | docs.polymarket.com/ | |
| How trading works | peer-to-peer | docs.polymarket.com/ | |
| The price an interface displays | the midpoint of the bid-ask spread | docs.polymarket.com/ | |
| What a buyer pays | the ask | docs.polymarket.com/ | |
| What the amount of a market buy is | the pre-fee USD notional | docs.polymarket.com/ | |
| Capping the whole cost of a market buy | an all-in spending limit | docs.polymarket.com/ | |
| Rebates for takers | the tiered Taker Rebate Program | docs.polymarket.com/ | |
| Taker fee rate, Crypto markets | 0.07 | docs.polymarket.com/ | |
| Taker fee rate, Sports markets | 0.05 | docs.polymarket.com/ | |
| Taker fee rate, Finance markets | 0.04 | docs.polymarket.com/ | |
| Taker fee rate, Politics markets | 0.04 | docs.polymarket.com/ | |
| Taker fee rate, Economics markets | 0.05 | docs.polymarket.com/ | |
| Taker fee rate, Culture markets | 0.05 | docs.polymarket.com/ | |
| Taker fee rate, Weather markets | 0.05 | docs.polymarket.com/ | |
| Taker fee rate, Tech markets | 0.04 | docs.polymarket.com/ | |
| Taker fee rate, Mentions markets | 0.04 | docs.polymarket.com/ | |
| Taker fee rate, Other / General markets | 0.05 | docs.polymarket.com/ | |
| Taker fee rate, Geopolitics markets | 0 | docs.polymarket.com/ |
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PolyTerminal is an independent interface for Polymarket and is not operated or endorsed by Polymarket. Orders placed through PolyTerminal carry PolyTerminal’s Polymarket builder code, and PolyTerminal may charge a builder fee on top of Polymarket’s own fees. This page is educational and is not investment advice. Rules were compared with the official documentation on Oct 19, 2026; check the source before you act on a number.