World Tennis Number (WTN) explained, and ratings in the UK

How WTN works

• It's a prediction system in the family of chess ratings: your number moves by how the actual result compared with what the numbers predicted.
• A confidence level shows how settled your number is. About 15 completed sets against suitable opponents in five weeks can reach high confidence.
• From 12 August 2026 the ITF moved to a rolling three-year window, game-level scoring, an adjustment for juniors and rating decay after long inactivity. Numbers shifted as a result, so older conversions don't hold.

Ratings in the UK

The LTA replaced its old LTA Ratings with WTN in late 2021, and WTN is now the official rating for all players in Britain, shown to one decimal place. The old scale ran from 10.2 at the bottom to 1.1 at the top. LTA rankings, which are points-based, are separate.

Where WTN is used

• Britain: the official rating, via the LTA.
• US college tennis: the ITA named WTN its exclusive official rating in January 2023.
• USTA: used for juniors, not for adult league play. League results still feed your WTN.