Tennis Win Probability Calculator
This turns two player ratings into a win probability using the Elo approach. Enter your rating and the opponent's.
Calculate tennis win probability
Fill in the fields and select Calculate.
What you'll need
To use the tennis win probability calculator, have these figures ready:
- Your rating — for example, 2000.
- Opponent rating — for example, 1900.
The calculator then returns the win probability the moment you press calculate.
How it works
Win probability = 1 ÷ (1 + 10^((opponent rating − your rating) ÷ 400))
You enter the your rating and opponent rating, and the calculator returns the win probability using the formula above.
When to Use
Use the tennis win probability calculator to estimate match outcomes based on Elo ratings or historical head-to-head performance. It is used by analysts to preview upcoming matches, by bettors to assess value in odds, and by fans to understand the expected difficulty of each match in a draw.
What the result tells you
A win probability near half marks an even contest, while a figure in the 70s or above signals a clear favourite. The estimate rests entirely on the ratings you supply and ignores surface, form and head to head history, all of which matter in tennis. Use it as a baseline and lean on those extra factors to refine the pick.
Benchmarks & Interpretation
Here is how typical results are categorized and interpreted:
| Value / Range | Rating | Description |
|---|---|---|
| Below 25% | Heavy underdog | The player faces a significantly stronger opponent. |
| 25 – 40% | Underdog | The opponent is favoured but an upset is possible. |
| 40 – 60% | Close match | A competitive match where either player could win. |
| 60 – 75% | Favourite | The player is expected to win but must perform well. |
| 75%+ | Strong favourite | A dominant player against weaker opposition. |
Pro Tips & Advice
Win probability models are guides, not guarantees — tennis is one of the most unpredictable sports because a single break of serve can swing a match. Surface plays a huge role: a clay court specialist's win probability drops significantly on grass and vice versa. Injury and recent form are not always captured by Elo models, so factor in recent news. For a more nuanced prediction, consider set-level win probabilities, which account for the match format (best-of-three vs best-of-five).
Step by step
- Enter the your rating.
- Enter the opponent rating.
- Select Calculate to read the win probability.
Worked example
A player rated 2000 against one on 1900 has a win probability of about 64 percent on paper.
Frequently asked questions
How is the tennis win probability worked out?
Win probability = 1 ÷ (1 + 10^((opponent rating − your rating) ÷ 400)). This turns two player ratings into a win probability using the Elo approach. Enter your rating and the opponent's.
Are tennis Elo ratings a real thing?
Yes. Tennis Elo ratings are widely used to rank players and forecast matches, and they often beat the official rankings at prediction.
How does the Elo system work in tennis?
Tennis Elo ratings increase after wins and decrease after losses, with the magnitude depending on the opponent's rating. Beating a higher-rated player earns more points than beating a lower-rated one. Separate ratings exist for each surface.
Are five-set matches harder to predict?
Yes and no. The better player is more likely to win a five-set match than a three-set match because the larger sample reduces variance. However, individual five-set matches can still produce upsets.
How accurate is the Tennis Win Probability Calculator?
The tool applies the standard formula exactly, so the result is only as accurate as the figures you enter. Double check your inputs, since a wrong number going in gives a wrong number coming out.
Is the Tennis Win Probability Calculator free to use?
Yes. Every tool on GamersZone is free, with no account and no limit on how many times you calculate. The maths runs in your browser, so the numbers you enter are never sent to a server or stored.
How we calculate this
This tool applies the standard formula shown above. The calculation runs entirely in your browser, so the figures you enter are never stored.