How to Compare American Odds and Decimal Odds Without Messing Up

Comparing American odds with decimal odds is easy once you know what each format says—and surprisingly easy to get wrong when you compare prices without checking the wager behind them. A number like +150 and a number like 2.50 can describe the same price. But -3 at -110 and -3.5 at -105 are not the same bet, even if the prices look close.

The useful habit is to compare both the odds format and the market: same game, Find more info same selection, same spread or total, and same period. Then check the price, note what you took, and compare it with the closing line later. This guide walks through the conversions, the basics of spreads, moneylines and totals, and how to use odds boards without letting format differences—or a stale screenshot—fool you.

American Odds and Decimal Odds: What the Numbers Mean

American odds are the familiar U.S. format. They use a plus or minus sign to show how a price relates to a $100 stake or a $100 potential profit:

Positive American odds, such as +150, show how much profit a $100 stake would make. At +150, a $100 winning bet returns $150 in profit, plus the original $100 stake.
Negative American odds, such as -150, show how much you need to stake to make $100 in profit. At -150, you’d need to risk $150 to earn $100 in profit.

Decimal odds show the total return for each unit staked, including the stake itself. At 2.50 decimal odds, a $10 winning bet returns $25 total: $15 in profit and your original $10 stake. That distinction matters. If you compare profit in one format with total return in another, your calculation will be off.

Decimal odds are common internationally, while American odds are standard at many U.S. sportsbooks. Some odds boards let you change the displayed odds format. Changing that setting changes how the price is written—not the bet’s underlying payout or chance estimate.

How to Convert American Odds to Decimal Odds

Use these formulas to convert the listed price. The result is decimal odds, including the returned stake:

For positive American odds: Decimal odds = 1 + (American odds ÷ 100)
For negative American odds: Decimal odds = 1 + (100 ÷ absolute value of American odds)

For example, +150 converts to 1 + (150 ÷ 100), or 2.50. At -150, the calculation is 1 + (100 ÷ 150), or about 1.67.

To convert the other way, start with the decimal price:

Decimal odds of 2.00 or higher: American odds = (decimal odds − 1) × 100
Decimal odds below 2.00: American odds = -100 ÷ (decimal odds − 1)

So decimal odds of 2.50 equal +150 American odds. Decimal odds of 1.67 are approximately -149. Rounding can cause a small difference, so don’t expect every displayed conversion to match digit for digit.

Quick Conversion Table

American odds Decimal odds Implied probability before accounting for vig +200 3.00 33.3% +100 2.00 50.0% -110 1.91 52.4% -150 1.67 60.0% -200 1.50 66.7%

Implied probability is a way to translate a price into a percentage. For decimal odds, divide 1 by the decimal price. For American odds, use 100 divided by the odds plus 100 for positive prices, or the absolute odds divided by the absolute odds plus 100 for negative prices. These are raw implied probabilities; sportsbook margin, often called the vig, means the probabilities on all outcomes may add up to more than 100%.

Compare the Same Wager Before Comparing the Price

This is the part that prevents most bad comparisons: make sure both prices refer to the closing line value same wager. Odds are not a standalone verdict. A price applies to a particular outcome, spread, total, player market, and game period.

Spreads

A point spread gives one team points for betting purposes and takes points away from the other. In football, Team A -3 has to win by more than three for a standard spread bet to win; Team B +3 can win outright or lose by fewer than three. A result exactly on the spread may be a push, depending on the market and sportsbook rules.

Compare the same spread number when shopping for price. Team A -3 at -110 is not the same wager as Team A -3.5 at -105. The second price may look more favorable, but the half-point changes which final scores win, lose, or push. Keep the line and the odds together when you write down a quote: -3 at -110, not just “-110.”

Moneylines

A moneyline is a bet on which team or competitor wins, without a point spread attached. The odds reflect the price of that selection. A favorite might be listed at -150 and an underdog at +130, for example. Compare the same team’s moneyline across books, and confirm that the market settles on the same game result. Rules for ties, draws, or dead heats can differ by sport and market.

Totals

A total, often called an over/under, is a bet on whether the combined score will finish above or below a posted number. If the total is 44.5, compare the price on Over 44.5 with the price on Over 44.5 elsewhere. Over 44.5 and Over 45 are different bets: a final score of exactly 45 would land on different sides of those numbers.

Match the Period and Settlement Rules

Check whether the odds are for the full game or a smaller slice, such as the first half, first period, or a team total. In soccer, double-check whether a result market covers the regular 90 minutes (plus stoppage time) or includes extra time. The same discipline applies in other sports: a regulation-time market and a game-winner market may settle differently. Don’t treat their prices as comparable just because the teams and event are the same.

Line Shopping Is About the Whole Price

Line shopping means checking multiple sportsbooks for the best available price on a market you actually want to bet. Odds boards for spreads, moneylines and totals can make this easier by putting prices in one view. OddsTrader, Oddschecker (US edition) and Action Network are examples of services bettors may use to follow odds and compare markets. Availability, sportsbook coverage and display features can vary, so confirm the details on the board and at the book before placing a wager.

Use the board to compare like with like. For a spread, note both the number and the price. For a moneyline, make sure you’re looking at the same selection and settlement rules. For a total, match the exact number and side. A best-price badge or highlighted cell is only useful if it refers to your market and is current.

Also check the odds format setting. One screen may show +125 while another shows 2.25. Those are equivalent prices, not competing offers. Convert them to a common format—or use the board’s format toggle—before deciding which book has the better price.

Opening Line vs. Current Price

An opening line is the price and market number first offered for an event. The current price is what a board or sportsbook is displaying now. Both are useful, but they answer different questions. Opening lines provide a reference point for how the market has moved. Current prices show the available quote at the time you check.

When available, use an odds board’s opening line and current price display to follow both parts of the market: the number and the odds. A football spread could open at -2.5 and later move to -3, while the price also changes. That’s not simply one number getting “better” or “worse”; the half-point and the price each affect the wager’s value.

A line move does not guarantee a particular result, and an opening price may no longer be available. Treat a screenshot as a record of what was shown at that moment, not as a reserved price. Sportsbook odds can change before you submit a bet, and the accepted price is the one to keep on your receipt.

Keep a Receipt: Price Taken and Closing Line

For every wager, record the event, market, selection, line, odds, sportsbook and time placed. For example: “Team A -3, -105, full game, placed at 1:12 p.m.” That gives you a useful receipt of what you actually bet—not just a note that you took Team A.

Later, compare your accepted price with the closing line: the market’s price near the start of the event, using the same market and, ideally, the same sportsbook or a consistent market reference. If you took -3 at -105 and the market closes -3 at -115, you got a better price than the close at that number. If it closes -2.5, note that the spread moved too. Don’t compare only the American or decimal price while ignoring a changed spread.

Closing-line comparison is a tracking tool, not a promise of profit or proof that every bet was good. It helps you review whether your line shopping and timing are consistently finding competitive prices. Keep the details consistent: same team, same market, same period, same line when comparing prices.

A Simple Checklist Before You Bet

Match the market: Confirm the event, selection, wager type and settlement period.
Match the number: Compare the same spread or total, not a nearby line.
Match the odds format: Convert American odds and decimal odds, or set the board to one format.
Compare the price: Check the available quote at the sportsbook, not only a cached screen or screenshot.
Record the bet: Save the accepted line and price as your receipt.
Review the close: Compare against the closing market on the same terms.

The Bottom Line

American odds and decimal odds are two ways to express the same payout. Convert them with the right formula, remember that decimal odds include the returned stake, and use implied probability as a reference rather than a guarantee. Most importantly, compare the entire wager—not just the number on the screen. A reliable odds format, a careful market match, and a record of the price taken will do more for line shopping than a quick glance at whichever figure looks bigger.