On an Over/Under market, you bet on a total — goals, points, games — against a line. On "Over 2.5 @ 1.90", Over is the selection, 2.5 is the line, 1.90 is the odd. A line ending in ".5" makes an exact tie with the total impossible, so no refund can happen. OddScore tracks this market in football and basketball, not in tennis.
Line and odd: two different things
On an Over/Under market, the line and the odd are not the same thing: the line is the threshold, the odd is the price.
Over 2.5 @ 1.90
Over = selection
2.5 = line
1.90 = odd
In "Over 2.5", the 2.5 represents the line, not the odd. This is the most common source of confusion on this market: the number next to Over or Under is never a price, it's always the threshold used to separate the two selections.
How an Over/Under market settles
Once the match is over, the actual total (goals, points or games depending on the sport) is compared to the line: Over wins if the total is strictly higher, Under wins if it's strictly lower.
| Score | Total goals | Over 2.5 | Under 2.5 |
|---|---|---|---|
| 0-0 | 0 | Lost | Won |
| 1-1 | 2 | Lost | Won |
| 2-1 | 3 | Won | Lost |
| 3-2 | 5 | Won | Lost |
Why the line often ends in .5
A line ending in .5 — like 2.5 — makes an exact tie with the total impossible, which rules out any refund.
The most common lines are 0.5, 1.5, 2.5 and 3.5. None of them can be hit exactly by a total of goals or points, which is always a whole number: the result is necessarily Over or Under, never a refund.
Some markets use whole-number lines, like 2.0 or 3.0, where an exact tie with the total becomes possible. How that particular case — and the split lines it produces — is handled belongs to the Asian Handicap, not this page.
Over/Under by sport
Over/Under is a market structure — a total compared to a line — that applies differently depending on the sport, not a bet specific to goals.
- Football — total goals scored in the match.
- Basketball — total points scored by both teams.
- Tennis — total games or sets, depending on the market offered by the operator.
The mechanism stays the same from one sport to another: only what's being counted changes.
Which sports does OddScore track this market on?
OddScore tracks the Over/Under market in football and basketball, but not in tennis.
| Sport | Markets tracked |
|---|---|
| Football | Winner (1X2), Over/Under |
| Basketball | Winner, Over/Under |
| Tennis | Winner only |
Tennis does expose a total-games market at some operators, but OddScore doesn't track it there — the reason is detailed on the page covering what OddScore analyzes in tennis. A page suggesting OddScore tracks Over/Under in tennis would be inaccurate.
The margin on a two-way market
Like any market, both sides of an Over/Under build in a margin: the sum of the implied probabilities of Over and Under usually exceeds 100%.
Example: Over 2.5 priced at 1.90 and Under 2.5 priced at 1.90 each give an implied probability of 52.63%, so 105.26% in total. The detail of this calculation, valid for any two-way market, is explained on the page dedicated to bookmaker margin — it isn't repeated here.
The line stays fixed, the price can move
The line on an Over/Under market doesn't necessarily change between opening and kickoff, but the odds attached to Over and Under can move. On some markets, the line itself can also be adjusted by the operator.
How to read these movements, and what they can reveal about the market, is explained in the dedicated guide to odds movements and on the page explaining why odds change.
Understand how OddScore analyzes odds movements →
Dig into the market
Odds movements are only part of the story. Here are the next topics to read.
Types of sports bets
Market, selection, line, odd: the main families of markets.
See the guideBTTS: do both teams score?
A market often correlated with Over/Under, without being equivalent.
See BTTSBookmaker margin
How the margin is built into both sides of a two-way market.
Understand the marginOdds movements
The line can stay fixed while the Over and Under prices move.
See movementsFrequently asked questions
What does Over 2.5 mean?
Over 2.5 means you're betting that the total (goals, points or games, depending on the sport) will be strictly higher than 2.5, so 3 or more.
What does Under 2.5 mean?
Under 2.5 means you're betting that the total will be strictly lower than 2.5, so 2 or fewer.
What does the 2.5 in Over 2.5 represent?
The 2.5 is the market's line, the threshold used to separate Over and Under. It isn't the odd: the odd is the price displayed separately for the selected side.
What happens with exactly 2 goals on an Over/Under 2.5 market?
Under 2.5 wins, since 2 is strictly lower than 2.5. A line ending in .5 can never be hit exactly, which rules out a refund on this type of line.
What's the difference between Over 2.5 and BTTS Yes?
Over 2.5 covers the total number of goals, regardless of which team scores them. BTTS Yes covers whether both teams score at least once each. A score like 3-0 wins Over 2.5 but loses BTTS Yes. The detail is covered on the page dedicated to BTTS.
Does Over/Under exist in tennis?
The principle exists (total games or sets), but OddScore doesn't track this market in tennis — bookmaker coverage there is judged insufficient, unlike in football and basketball.
Does Over/Under exist in basketball?
Yes, on the total points. It's one of two markets OddScore tracks in basketball, alongside the winner market.
Sources & methodology
This page combines standard Over/Under market vocabulary, settlement rules published by Betfair, a licensed operator, and OddScore's own observation of Over/Under odds offered by several operators in football and basketball.
- Explicitly distinguish the line, the selection and the odd, using numeric examples checked before publication.
- State which sports OddScore actually tracks this market on, and which it doesn't.
- Check every settlement table against the totals it describes.
- Betfair — Exchange general rulessupport.betfair.com
- Betfair — Charges and commissionbetfair.com
- UK Gambling Commission — Definitions of terms