You have been handed a number you do not understand. A tournament entry form asks for your WTN, a federation app shows “WTN 24.3”, or a new hitting partner says they are “a 19” and you cannot tell whether that is impressive. The part that trips almost everyone up is simple: the World Tennis Number runs backwards. A lower number is the stronger player.
This guide explains what the ITF World Tennis Number is, how the scale works, what the confidence marker means, and how to use your number without over-reading it. If you want to compare it with other systems, we cover that separately in UTR vs NTRP vs WTN.
What the World Tennis Number is
The World Tennis Number (WTN) is a free global rating system created by the International Tennis Federation (ITF). It applies to players of all ages, genders and abilities, and the ITF’s aim is a single standard that national federations can share, rather than every country keeping its own scale.
According to the USTA, WTN is used for tournament seeding, collegiate tennis evaluation and junior team tennis, and the ITF describes it as accepted across more than 170 countries. In practice that means you are most likely to meet it through a federation event, a national tennis app or an international junior or college pathway.
The scale: 40 down to 1
WTN runs on a 40-to-1 scale. 40 is a beginner and 1 is an elite professional. Everyone else sits somewhere in between, and a number such as 22 simply means you are stronger than a 30 and weaker than a 15.
Three things follow from that design:
- Everyone shares the scale. Men, women, juniors and adults are all placed on the same line. That is different from many club ladders, which are split by age or gender.
- The numbers carry decimals. You will see values such as 24.3, not just whole numbers. The decimals matter when you compare two players, but they are not precise enough to settle an argument.
- Top professionals are handled differently. The WTN site says ATP and WTA Top 500 players are excluded from public search under agreements with those tours, although their ratings still update weekly.
The direction problem
If you play in a country where NTRP is common, you are used to higher meaning better: 3.0 is weaker than 4.0. UTR works the same way, from 1.00 up to 16.50. WTN is the exception. Read “WTN 15” as stronger than “WTN 30”, and never compare a WTN to a UTR as if they pointed the same direction.
A quick mental check: if the number is going down as the player gets better, you are looking at WTN.
How WTN is calculated
The ITF does not publish the formula, but its public explanations give a clear picture of the approach.
It looks at sets, not just wins
The WTN site says the algorithm compares predicted outcomes with actual scores, and that it treats each set as its own result while factoring in the game score. So a 7-5 set tells the system something different from a 6-0 set, even though both are set wins. This is also why a narrow loss to a much stronger player is not necessarily bad for your number: you lost, but you did better than expected.
The USTA contrasts this with NTRP, which it describes as being based on ranking points. WTN works at set level, and the two systems use distinct algorithms and different match data, so they will not agree exactly.
Singles and doubles are separate
You get two ratings. The WTN site is explicit that the singles algorithm only takes singles matches into account and the doubles algorithm only doubles matches. A player who plays mostly doubles at a social club may therefore have a confident doubles number and an unreliable, or missing, singles one.
This is one of the biggest differences from NTRP, which gives a single combined rating.
What counts as a match
Completed sets count. A retirement counts if a sufficient number of games have been played before it occurs. The ratings only reflect matches reported by participating organisers and federations, so a hard-fought match on a public court with friends does not move your number at all.
How far back it looks
Here the official sources describe it slightly differently, so treat the detail with care. The USTA describes a rolling three-year rating window. The WTN FAQ says the algorithm uses match results from 2016 onward. Either way, the practical advice is the same: recent results matter, old results fade in relevance, and a long break from competitive matches leaves your number resting on old data.
How often it changes
The ITF says WTN is calculated and published once a week, and the WTN site says that happens every Wednesday. Compare that with the annual NTRP release: if you improve quickly, WTN can reflect it within weeks, provided you are entering rated matches.
Confidence: the blue tick and the grey tick
Next to a WTN you will usually see a confidence marker.
| Marker | What it means | What to do with it |
|---|---|---|
| Blue checkmark | High level of confidence in the rating | Reasonable to treat as a good guide |
| Grey | Lower confidence | A starting estimate, expect it to move |
Confidence rises as more matches are recorded. The WTN site notes that players now receive an initial rating from their first matches rather than starting at 40, so a new rating can reflect your level from the outset, but it begins at lower confidence. The site also says playing regularly helps keep a rating from declining.
The takeaway: a grey WTN is a hypothesis. A player with three recorded matches and a grey 28 might be a 22 who had a bad day. A player with a blue 28 and dozens of matches is almost certainly around 28.
How to read your own number
Rating sites love tables that map numbers to skills. The ITF publishes its own written descriptions of the bands, and you should read those rather than trust any third-party chart, including ours. What we can offer is a way of reasoning about it.
Think in neighbourhoods
A difference of one or two points means very little. A difference of ten means a lot. If you are a 30 and your hitting partner is a 28, expect an even match. If they are a 20, expect to be run around the court.
Remember the scale is stretched at the ends
At the beginner end, many players are packed together and the numbers are noisier. At the top, a few points separate a very strong club player from a serious tournament competitor. The middle is where the number is most useful for finding a fair game.
Check singles versus doubles
Before you quote a number, say which one it is. “I’m a 26 in doubles” and “I’m a 26 in singles” are different claims, and an experienced player will ask.
Check the confidence
If your number has a grey marker, say “my WTN is about 28 but it’s new”. It sets honest expectations and avoids you being placed in a group where you do not belong.
WTN versus NTRP and UTR, briefly
You do not need a full conversion to understand the differences.
- WTN: ITF, 40 to 1, lower is stronger, separate singles and doubles, updated weekly.
- NTRP: USTA, 1.5 to 7.0 in half-point steps, higher is stronger, one combined rating, published annually.
- UTR: UTR Sports, 1.00 to 16.50, higher is stronger, built from results entered on its platform.
There is no official conversion between WTN and NTRP; the USTA says plainly that there is no direct one-to-one comparison. For a longer look at the differences between all three, read our overview of tennis rating systems and the more detailed comparison. For the USTA scale on its own, see NTRP ratings explained.
Common mistakes with WTN
- Treating a lower number as worse. It is the other way round. This is by far the most common error.
- Quoting one number for both disciplines. Your doubles and singles ratings are independent.
- Trusting a grey number too much. Early ratings move quickly.
- Expecting social games to count. Only matches reported through participating organisers feed the system.
- Comparing it to a UTR directly. Different algorithms, different data, different direction.
- Obsessing over decimals. A 0.5 difference is within the noise.
What if you do not have a WTN?
Plenty of recreational players never get one. That is fine. A rating is a tool for finding fair matches, and there are other ways to do that.
A short skills description is often more useful than a number: how long your rallies last, whether your second serve holds up under pressure, whether you can play a full set without your level collapsing. Our guide to social tennis covers the formats that work without any rating.
If you are in Bangkok, the club directory and the Bangkok courts hub are a good starting point for finding somewhere to play. Many clubs place players by watching them hit rather than by checking a number.
Matching by level without a rating
Breakers Open Play is built around that idea. It runs level-matched, drop-in social sessions where you book a seat in a session for your level and play with people at about your standard, no partner needed. It runs in Bangkok for now. You do not need a WTN, a UTR or an NTRP to join: you choose the level that matches how you play, and the sessions help you calibrate. You can see upcoming sessions and pick your level.
The practical takeaway
- WTN is the ITF’s global rating, on a 40-to-1 scale. Lower is stronger.
- You have separate singles and doubles ratings.
- It updates weekly and looks at set-level results, so recent matches matter.
- Check the confidence marker before you trust a number.
- It does not convert exactly to NTRP or UTR. Use ranges, and confirm on court.
- No number? Describe your game in plain words and play someone to check.
A rating is a shortcut to a good match. The first few games will tell you more than the decimal.
Sources
- ITF World Tennis Number (USTA): https://www.usta.com/en/home/play/itf-world-tennis-number.html
- World Tennis Number FAQ (ITF): https://worldtennisnumber.com/eng/faq
- NTRP Ratings FAQs (USTA): https://www.usta.com/en/home/play/adult-tennis/programs/national/usta-ntrp-ratings-faqs.html
- What is the ITF World Tennis Number? (LTA): https://www.lta.org.uk/support-centre/competing/world-tennis-number/activating-my-wtn/what-is-the-itf-world-tennis-number2/
Frequently asked questions
What is a good World Tennis Number?
It depends on what you want to do. Because the scale runs from 40 (beginner) to 1 (elite professional), a lower number is stronger. There is no official 'good' threshold, so judge it against the players you want to compete with: a number that puts you near the middle of your local pool is a good match for social and club play.
Is a lower WTN better?
Yes. WTN is a 40-to-1 scale where 40 is a beginner and 1 is an elite professional. This is the opposite of UTR and NTRP, where a higher number means a stronger player.
How often does World Tennis Number update?
The ITF says WTN is calculated and published weekly. The WTN site says the update happens every Wednesday.
Do I get separate WTN ratings for singles and doubles?
Yes. The singles rating only uses singles matches and the doubles rating only uses doubles matches, so the two numbers can differ a lot.
What does the WTN confidence marker mean?
A blue checkmark indicates a high level of confidence in the rating, while grey indicates lower confidence. More recorded matches raise confidence, and a brand-new rating starts at a lower level.
