Tennis surfaces: how clay, grass, hard and indoor courts change your bets
In tennis the surface changes the serve most, and with it games and tie-breaks. On grass men hold serve in 81.5% of their service games and serve 13.1 aces per match on average; on clay it is 72.1% and 6.3 aces. A tie-break was played in 44% of men's matches on grass and 28% on clay, and total games rose from 22.4 on clay to 24.5 on grass. The match result, though, is almost equally predictable on every surface: favourites win 67–70% of matches. We checked 51,179 ATP, WTA and Challenger matches from 2024–2026 and the serve stats of the last 12 months.
Key takeaways
- Over 22.5 games in men's matches lands in 50.5% of matches on grass and 40.7% on clay, so compare the line with the surface average.
- 6–0 sets are more common on clay: one came up in 9.1% of men's matches there and in 2.8% on grass.
- Retirements ended 3.7% of matches on outdoor hard courts and only 1.9% on grass.
- The grass season is short, so a player's grass record is often only a few matches a year and easy to overrate.
Four surfaces and the calendar
- Clay: a slow ball with a high bounce. The season runs in spring (April–June, with Roland Garros) and through smaller summer events, and in South America also in February. It is 41% of the matches in our sample, almost half in Challengers and as many as 59% in WTA 125 events.
- Outdoor hard court: the "middle" surface. The Australian Open, the US Open and most events from January to March and from August to October. 41% of matches, 58% in the WTA.
- Indoor: a hard court under a roof, with no wind or sun, usually faster. Mostly in autumn and at the start of the year. 10.5% of matches.
- Grass: the fastest surface, with a low bounce. Only a few weeks in June and July, with Wimbledon. 7.3% of matches, 2.4% in Challengers.
The terms used below (holding serve, breaking serve, tie-break, 6–0 set) are explained in our tennis glossary.
Every difference in one table
Men (ATP and Challengers), best-of-three matches:
| Clay | Hard court | Indoor | Grass | |
|---|---|---|---|---|
| Matches | 15,413 | 13,006 | 4,819 | 1,679 |
| Average games | 22.4 | 22.8 | 23.2 | 24.5 |
| Over 22.5 games | 40.7% | 42.4% | 45.0% | 50.5% |
| Went to a third set | 34.6% | 34.1% | 34.7% | 36.4% |
| Sets ended by a tie-break | 13.6% | 15.9% | 18.6% | 22.3% |
| Matches with a tie-break | 28.3% | 32.2% | 37.3% | 44.1% |
| Matches with a 6–0 set | 9.1% | 6.6% | 4.7% | 2.8% |
| Service games held | 72.1% | 76.9% | 80.3% | 81.5% |
| Aces per match | 6.3 | 10.2 | 12.5 | 13.1 |
| Favourite won | 69.0% | 68.3% | 67.6% | 67.0% |
Women (WTA and WTA 125), best-of-three matches:
| Clay | Hard court | Indoor | Grass | |
|---|---|---|---|---|
| Matches | 5,317 | 7,272 | 556 | 1,709 |
| Average games | 21.5 | 21.8 | 21.1 | 22.4 |
| Over 21.5 games | 41.7% | 43.0% | 39.6% | 46.3% |
| Went to a third set | 33.5% | 33.5% | 29.1% | 35.7% |
| Sets ended by a tie-break | 9.4% | 10.2% | 9.7% | 12.8% |
| Matches with a tie-break | 20.4% | 22.0% | 20.0% | 26.4% |
| Matches with a 6–0 set | 14.2% | 11.7% | 14.4% | 9.0% |
| Service games held | 58.7% | 65.3% | 64.8% | 69.0% |
| Aces per match | 3.1 | 5.3 | 4.9 | 6.7 |
| Favourite won | 69.6% | 68.3% | 68.4% | 68.7% |
Service games held and aces come from the serve stats of the last 12 months (21,648 matches), everything else from the 2024–2026 matches. There are few women's indoor matches in the sample (556), so treat those figures with more caution.
What the surface changes and what it does not
It changes: serve, games and tie-breaks
The faster the surface, the easier it is to hold serve. From clay to grass the men's hold rate rises by almost 10 percentage points and aces double. So more sets reach 6–6: 13.6% of sets end in a tie-break on clay and 22.3% on grass. Every tie-break makes for a longer set, so total games go up, and over 22.5 games in men's matches lands in every other match on grass and in four out of ten on clay.
On clay it is the other way round: more breaks, more one-sided sets and more 6–0 sets (in 9.1% of men's matches, against 2.8% on grass). The serve figures are in our article on aces and double faults, and the tie-break figures in our article on tie-breaks.
It does not change: how predictable the result is
The favourite wins 67–70% of matches on every surface, and the way that compares with the chance implied by the odds is similar everywhere. On clay favourites are marginally safer (69.0% for men against 67.0% on grass). One explanation: clay has fewer tie-breaks, and in a tie-break the favourite's edge clearly shrinks. Still, these are differences of about two percentage points. How often the favourite wins at each price is shown in our article on favourites in tennis.
The first set matters just as much everywhere: its winner wins the match in 81–82% of cases on every surface. More in our article on first set and set betting.
Retirements: fewest on grass
Retirements ended 3.7% of matches on outdoor hard courts, 3.4% on clay, 2.7% indoors and only 1.9% on grass. What that means for your bet is covered in our article on retirements in tennis.
What it means for your bets
- The games line has to depend on the surface. The same 22.5 line is nearly a coin toss on grass and a bet that lands in four matches out of ten on clay. Bookmakers take this into account, so compare the line with the average for that surface, not for the whole tour.
- Tie-breaks and aces are fast-court markets. Men's matches on grass and indoors have the most of them, but bookmakers know that too: a higher chance means lower odds.
- Players have their surfaces too. Tour averages are only the backdrop. We show a player's record on the surface over the last 12 months and their surface-adjusted Elo on the match page and in the player profile.
- A small sample on grass. The grass season is short, so a player's grass record is often only a few matches a year. It is easy to draw conclusions from such a sample that go too far.
On our tennis tips every match shows its surface, and we compare the chances for games and a tie-break with the tour average on the same surface. Player rankings with overall and surface Elo are in our tennis rankings. For the full introduction, see tennis betting in numbers.
FAQ
Which tennis surface produces the most games?
Grass. Men's best-of-three matches average 24.5 games there, 23.2 indoors, 22.8 on outdoor hard courts and 22.4 on clay. For women it ranges from 21.1 indoors to 22.4 on grass.
Where are tie-breaks most common?
On grass. In men's tennis 22.3% of sets end in a tie-break there, and at least one tie-break is played in 44% of matches. On clay it is 13.6% of sets and 28% of matches.
Are there more upsets on clay?
No. On clay favourites win marginally more often than on the other surfaces: 69.0% of men's matches and 69.6% of women's. On grass it is 67.0% and 68.7%.
Why are there more aces on grass?
Grass is the fastest surface with the lowest bounce, so the serve is harder to return. Men serve 13.1 aces per match on grass on average and 6.3 on clay, and hold in 81.5% of their service games against 72.1% on clay.
How many tennis matches are played on each surface?
In our 2024–2026 sample: 41% of matches on clay, 41% on outdoor hard courts, 10.5% indoors and 7.3% on grass. In the WTA hard courts dominate (58%), while clay is the most common surface in Challengers and WTA 125 events.