A tennis ELO rating for amateurs is a single number that goes up when you win, down when you lose, and moves more when the result is a surprise. Everyone starts at the same number (usually 1000 or 1500). Beat someone rated well above you and you gain a lot; beat someone well below you and you gain almost nothing. That's the entire trick, and it's why ELO works so well for a friend group: it doesn't care how many matches you play, only who you beat and how unlikely it was. You don't need a federation membership or official tournaments to have one — you need a consistent record of results between the people you actually play. Rackt runs an ELO for every private group automatically, free on iOS and Android. Here's how it works and how it stacks up against the official systems.
How ELO actually calculates your rating
Before every match, the system works out an expected result for each player based on the rating gap. Two players at the same rating each have a 50% expected chance. A 200-point gap makes the higher-rated player roughly a 75% favourite.
After the match, your rating changes by:
K × (actual result − expected result)
The actual result is 1 for a win, 0 for a loss. K is a sensitivity dial — higher K means bigger swings. So if you were a 75% favourite and won, you gain K × 0.25. If you were the 25% underdog and won, you gain K × 0.75, three times as much. Your opponent loses exactly what you gain, so the pool stays balanced.
The system was invented by Arpad Elo for chess, and the Wikipedia article on the Elo rating system covers the maths in more depth than anyone at your club will ever want. We've also walked through upsets and score margins in padel ELO ratings explained — the logic transfers to tennis unchanged.
ELO vs the official tennis ratings
Amateurs often ask whether they should just use an official rating instead. The honest answer: those systems measure you against the world. ELO in a private group measures you against the people whose names you actually shout across the net.
| Group ELO | UTR | NTRP (USTA) | World Tennis Number (ITF) | |
|---|---|---|---|---|
| Scale | Open-ended, starts ~1000 | 1–16.5 | 1.0–7.0 | 40 (beginner) to 1 (pro) |
| Who rates you | Your group's results | Match results in the UTR network | Self-rating, then league results | Results in eligible competition |
| Needs official matches | No | Mostly | Yes, for a computer rating | Yes |
| Reacts to upsets | Yes | Yes | Slowly | Yes |
| Useful for "who's best in our group?" | Very | Somewhat | Barely | Somewhat |
The ITF's World Tennis Number is the closest cousin to ELO: it rewards surprising wins, punishes unexpected losses and weights recent matches more heavily. But friendly Tuesday doubles doesn't feed into it, which is exactly the tennis most amateurs play.
Why win percentage lies
The default friend-group ranking is "who's won the most." It breaks immediately. Say Sam plays the two weakest players in the group every week and wins 80%. Priya plays everyone, including the club's former junior, and wins 55%. Win percentage puts Sam top. Everybody knows that's wrong, including Sam, though he'll never admit it.
ELO fixes this without anyone having to argue about schedules. Sam's wins over low-rated players earn tiny amounts; Priya's wins over the strongest player earn big ones. After twenty or so matches the table matches what everyone privately suspected, which is both satisfying and slightly painful.
If you'd rather keep a challenge-based structure, a ladder can work alongside a rating — the trade-offs are in how to run a tennis ladder with friends.
Setting up ELO for your group
Pick a K and stick with it. Around 32 suits small groups where people play a few times a month; it moves fast enough to feel alive. Big, frequent groups can drop it lower for stability.
Decide what counts as a match. Best of three, one set, or a match tiebreak — choose once. Mixing a 10-point tiebreak with a three-setter gives both the same weight, which isn't ideal.
Separate singles and doubles. Doubles results depend on your partner. Keeping one combined number muddies both. The same goes for tennis and padel — track them apart.
Get both players to confirm. A rating is only as honest as its inputs. One-sided logging means someone eventually "forgets" a loss.
Ignore the first handful of matches. Everyone starts equal, so early ratings are noise. Give it ten matches per person before anybody screenshots the table.
You can do all this in a spreadsheet if you enjoy formulas. Or you can let an app handle the expected-score maths, confirmations and history for you — Rackt does exactly that, per group and per sport, and it's free to download.
What a good amateur rating should show you
The number alone is only half the story. The useful context around it:
- Rating history, so you can see whether that new forehand is doing anything.
- Head-to-head records, because your rating says you're better than Marco but your record against him says 2–7.
- Form and streaks, to show who's hot right now rather than who was good in spring.
- Win probability before a match, which is ELO's expected score dressed up for the group chat.
For the broader question of what to look for in a tracking app, see the best app to track tennis matches with friends.
FAQ
Can amateur tennis players have an ELO rating?
Yes. ELO only needs a record of who played whom and who won, so any group of amateurs can run one. It doesn't require official competition — a private group logging consistent, confirmed results is enough for the rating to become accurate after a couple of dozen matches.
Is ELO better than UTR for a group of friends?
For ranking a specific group, usually yes. UTR places you on a global scale using results from its network, which is useful for tournament entry but says little about who's best among your eight regulars. A group ELO is calculated only from your group's matches, so it answers that question directly.
What's a good starting ELO for tennis?
The starting number doesn't matter as long as everyone gets the same one; 1000 and 1500 are common. What matters is the gaps that develop between players, since those drive the expected results.
Should doubles count toward my singles ELO?
Keep them separate. Doubles results depend heavily on your partner, so mixing them into a singles rating adds noise. Most group trackers, including Rackt, track formats and sports independently.
Stop ranking your group by who talks loudest after the match. Log it, confirm it, let the number decide. Download Rackt free.
Rackt: private tables, honest ratings, and the head-to-head your mate hoped you'd forget.