MoneyRules

Tennis aces props: counting the unreturned serves

An aces prop asks whether a player, or both players, serve more or fewer aces than a line, such as 8.5. An ace is a legal serve the returner does not touch.

Reviewed Oct 15, 2026

Answer first

90s

01An ace is a serve the returner never touches.
02Grass and fast courts produce more aces.
03Best-of-five matches have higher lines.

Key numbers

Aces props at a glance

8.5Common lineBig server

3.5Common lineBaseliner

15.5Match totalTwo big servers

-115Typical priceEither side

In short

Key takeaways

Only untouched legal serves count.
Surface changes ace rates a lot.
Longer matches mean more aces.
Retirement rules vary by book.

Progress

How an ace is counted

1
Serve
Lands in the box
2
Returner
Does not touch it
3
Ace
Point won
4
Match ends
Stats checked
5
Grade
Over or under

Official match stats settle the bet.

Example aces lines

Player type	Surface	Line	Over
Big server	Grass	14.5	-110
Big server	Clay	7.5	-115
All-court player	Hard	5.5	-105
Baseliner	Clay	2.5	+105
Women’s top server	Hard	4.5	-110

Made-up prices for illustration.

What counts as an ace

The serve must land in the service box and the returner must not touch it. If the returner gets a racquet on it, it is not an ace, even if the return is weak.

A let serve that clips the net and lands in is replayed, so it is not an ace. Second-serve aces count the same as first-serve aces.

Service winners, where the returner touches the ball but cannot return it, are not aces. Some data feeds track both separately.

Surface and ace rate

Surface	Aces per service game	Speed
Grass	1.0	Fastest
Indoor hard	0.85	Fast
Outdoor hard	0.7	Medium
Clay	0.45	Slowest

Rough averages for a big server; our own estimates.

What moves the line

Match length matters most. A tight match with tiebreaks gives more service games than a quick straight-sets win.

The returner matters. Strong returners touch more serves, which cuts aces even on fast courts.

Conditions matter. Altitude and warm, dry air make the ball fly faster, while cold and damp air slows it down.

Sequence

Checking an aces prop

Step 01
Check the surface
Grass, hard or clay.
Step 02
Look at the format
Best of 3 or 5.
Step 03
Study the returner
How many serves he touches.
Step 04
Expect match length
Close or one-sided.
Step 05
Compare lines
Half an ace matters.

Rules and settlement

If a player retires mid-match, books differ. Some void all ace bets, while others settle if the result is already decided.

Books name a data source, usually the official match stats. Small differences between feeds can matter on close lines.

Walkovers before the match starts usually void all bets on that match.

Floor rules

Aces terms

Know before you sit

Ace: Untouched legal serve.
Service winner: Touched but not returned.
Let: Serve clips net, replayed.
Retirement: Player quits mid-match.

A worked example

A big server has an aces line of 12.5 at -110 on grass in a best-of-three match. He averages about 1.0 ace per service game on grass.

The match goes three sets, including two tiebreaks, and he serves 17 games. He hits 15 aces, so the over wins. A $11 bet returns $21, a profit of $10.

If he had won in two quick sets with 10 service games, he might have finished with 9 or 10 aces, and the under would have won. Expected match length is the key input. Close matchups with two strong servers often go long.

Common mistakes

Ignoring the surface: Clay cuts aces.
Forgetting the returner: Good returners touch more.
Mixing up formats: Best of 5 adds games.
Skipping retirement rules: Rules vary.

Keep reading

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After the 90 seconds

Questions before and after you play

A 90-second guide cannot cover every table moment. Tap a group, then a question — answers are short paragraphs, not one-liners.

01Basics

What is an ace?

A legal serve that lands in and that the returner does not touch at all. Rules differ between licensed sportsbooks, so read the house rules.

Do second-serve aces count?

Yes. Any ace counts, whether on a first or second serve. Rules differ between licensed sportsbooks, so read the house rules.

Is a service winner an ace?

No. If the returner touches the ball, it is not an ace. Rules differ between licensed sportsbooks, so read the house rules.

02Rules

What if a player retires?

Books differ. Some void the bet, others settle if the result is already certain.

What about walkovers?

If the match never starts, bets are usually void. Rules differ between licensed sportsbooks, so read the house rules.

Which stats are used?

The data source named in the book’s house rules, usually official match stats. Rules differ between licensed sportsbooks, so read the house rules.

03Strategy

Which surface has the most aces?

Grass, followed by fast indoor hard courts. Clay has the fewest. Rules differ between licensed sportsbooks, so read the house rules.

Do longer matches help the over?

Yes. More service games mean more chances for aces. Rules differ between licensed sportsbooks, so read the house rules.

Where can I get help?

If betting stops being fun, call or text 1-800-GAMBLER for free, private help any time of day.

Sources

ATP Tour — Stats Not from a registry (Reference source, not an official registry) · accessed Oct 15, 2026Serve and return statistics
ITF — Rules of Tennis Not from a registry (Reference source, not an official registry) · accessed Oct 15, 2026Official rules of tennis
Wizard of Odds — Sports betting Not from a registry (Reference source, not an official registry) · accessed Oct 15, 2026Sports betting math
National Council on Problem Gambling — Help and resources Not from a registry (Reference source, not an official registry) · accessed Oct 15, 2026Free, confidential help: call or text 1-800-GAMBLER