Tennis Court Dimensions Interpreter
Tennis Court Dimensions Interpreter
Measure a court and find out whether it is an ITF court marked for doubles, an ITF singles-only court, or neither. One governing body, one specification, and the only difference between the two codes is a tramline on each side.
Which court is this?
Measurements ⇄ Rule 1A court measured 23.77 m long and 10.97 m wide, with the net 0.914 m at the centre
Rule 1, in both units, with the exact conversion beside the printed one
| Dimension | Rule 1, imperial | Rule 1, metric as printed | Exact conversion | Singles or doubles |
|---|---|---|---|---|
| Length, baseline to baseline | 78 ft | 23.77 m | 23.7744 m | Both — identical |
| Width | 27 ft | 8.23 m | 8.2296 m | Singles |
| Width | 36 ft | 10.97 m | 10.9728 m | Doubles |
| Tramline (doubles alley), each side | 4 ft 6 in | not printed as a figure | 1.3716 m | The difference between the codes |
| Service line, from the net | 21 ft | 6.40 m | 6.4008 m | Both — identical |
| Service box width, sideline to centre service line | 13 ft 6 in | not printed as a figure | 4.1148 m | Both — identical |
| Net height at the centre | 3 ft | 0.914 m | 0.9144 m | Both |
| Net height at the posts | 3 ft 6 in | 1.07 m | 1.0668 m | Both |
| Net post centres, outside the court | 3 ft | 0.914 m | 0.9144 m | Outside the doubles court, or outside the singles court with a singles net |
| Centre mark on each baseline | 4 in | 10 cm | 0.1016 m | Both |
The areas, and what the two codes actually differ by
| Area | Square feet | Square metres | Working |
|---|---|---|---|
| Singles court | 2,106 | 195.6538 | 78 × 27 |
| Doubles court | 2,808 | 260.8717 | 78 × 36 |
| Difference | 702 | 65.2179 | 2,808 − 2,106 |
| One tramline | 351 | 32.6090 | 78 × 4.5 |
| Two tramlines | 702 | 65.2179 | 2 × 351 — the whole difference |
| One service box | 283.5 | 26.3380 | 21 × 13.5 — identical in both codes |
| All four service boxes | 1,134 | 105.3520 | 4 × 283.5 |
| Service boxes as a share of the singles court | 53.8% | 53.8% | 1,134 ÷ 2,106 |
| Service boxes as a share of the doubles court | 40.4% | 40.4% | 1,134 ÷ 2,808 |
One rule book, one court, and two tramlines
Tennis is unusual among the sports on this site in having one specification for its playing area and one body that publishes it. An association football pitch length is a permitted range; an ice hockey rink has two rule books that disagree about it, so a rink built to the NHL’s figures fails the IIHF’s on both axes. A tennis court is 78 feet long and either 27 or 36 feet wide, everywhere, and Rule 1 of the ITF Rules of Tennis 2026 is the only document that says so. Those figures were read again in the 2009 edition of the same rules, hosted elsewhere, and every one is identical — which matters here, because the court plan in the 2026 edition’s Appendix IX came back from the fetch as a caption with no numbers in it, so the dimensions on this page rest on Rule 1’s prose and on a second independent copy of that prose.
Rule 1 prints every dimension twice, in feet and inches and in metres, and the metric figures are rounded conversions of the imperial ones rather than the other way round. The arithmetic shows it: 78 feet is 23.7744 m and Rule 1 prints 23.77 m; 27 feet is 8.2296 m and it prints 8.23 m; 3 feet is 0.9144 m and it prints 0.914 m. So an area worked from the printed metric figures is a few hundredths of a square metre out, and an area worked from the imperial figures is exact.
The singles and doubles difference is the content of this page, and it is smaller than it feels. The length is the same. The service boxes are the same: Rule 1 draws the service lines “between the singles sidelines, 21 feet (6.40 m) from each side of the net”, so a service box is 21 feet deep and 13 feet 6 inches wide in both codes, and a doubles serve has precisely no extra court to land in. What doubles adds is two tramlines, 4 feet 6 inches each, along the full 78-foot length — 351 square feet apiece and 702 square feet together, which is the whole of the 2,808 against 2,106 square feet in the table above. A doubles court is a singles court with the alleys painted in, which is why one court can host both and why a singles-only court cannot host doubles.
Two measurements go wrong often enough to be worth naming. The net is 3 feet 6 inches at the posts and 3 feet at the centre, held down by a strap — a tennis net is designed to sag about 15 centimetres — so a net measured at a post reads 15 centimetres high and is not faulty. And the width Rule 1 specifies is the court, not the space: Tennis Australia’s planning guidance recommends 5.48 m (18 ft) behind each baseline and 3.05 m (10 ft) at the sides as run-off for a club court, and a tape run to a fence rather than to a painted line picks that up. Tennis Australia also gives the line widths, which Rule 1 covers too: between 1 inch and 2 inches generally, up to 4 inches for a baseline, and 2 inches for the centre service line and the centre mark. Every rule quoted on this page is printed with the body that publishes it and the edition or year it belongs to. A tennis rule is a regulation rather than a fact: the deciding set was changed at two of the four Grand Slam tournaments in 2019 and at three of them in 2022, and in between those two years the four ran four different deciding-set rules at the same time. For the rules played on this court see the match score and sets interpreter and the tie-break and set format interpreter.
Frequently asked questions
What are the dimensions of a tennis court?
78 feet (23.77 m) long, and 27 feet (8.23 m) wide for singles or 36 feet (10.97 m) wide for doubles, under Rule 1 of the ITF Rules of Tennis 2026. The service lines are 21 feet (6.40 m) from the net on each side, and the net is 3 feet (0.914 m) high at the centre and 3 feet 6 inches (1.07 m) at the posts.
How much bigger is a doubles court than a singles court?
702 square feet, or about 65.2 m² — exactly two tramlines of 4 feet 6 inches along the full 78-foot length. A singles court is 2,106 square feet and a doubles court 2,808. The length is identical and so is every service box.
Is the service box bigger in doubles?
No, and this surprises almost everybody. Rule 1 draws the service lines between the SINGLES sidelines, so a service box is 21 feet by 13 feet 6 inches — 283.5 square feet — in both codes. A doubles serve must land in exactly the same area as a singles serve. The tramlines are in play only once the ball is in.
How high is a tennis net?
3 feet (0.914 m) at the centre and 3 feet 6 inches (1.07 m) at the posts, under ITF Rule 1, with the centre “held down tightly by a strap”. The sag is deliberate, so a net measured at a post reads about 15 centimetres higher than the figure most people have in mind. The net posts’ centres sit 3 feet (0.914 m) outside the doubles court on each side.
Are the ITF’s metric figures or its imperial figures the real ones?
The metric figures printed in Rule 1 are rounded conversions of the imperial ones, and the rounding shows it: 78 feet is 23.7744 m and the rule prints 23.77 m, 27 feet is 8.2296 m and it prints 8.23 m, 3 feet is 0.9144 m and it prints 0.914 m. For measuring a court the difference is irrelevant; for computing an area it is not, which is why the area table on this page works from the imperial figures.
Why does a tennis court have a centre mark on the baseline?
Because the server has to stand on one side of it. Rule 1 specifies it as 4 inches (10 cm) long and 2 inches (5 cm) wide, and it divides each baseline in half so the deuce and advantage halves of the court are defined. It is the smallest dimension in Rule 1 and the one most often missing from a repainted club court.
Related calculators
References
- International Tennis Federation. Rules of Tennis 2026, Rule 1 — The Court. itftennis.com/media/7221/2026-rules-of-tennis-english.pdf, © ITF Limited 2025. “78 feet (23.77 m) long”; “27 feet (8.23 m) wide” for singles and “36 feet (10.97 m) wide” for doubles; service lines “21 feet (6.40 m) from each side of the net”; net “3 feet (0.914 m) at the centre” and “3 ½ feet (1.07 m)” at posts whose centres are “3 feet (0.914 m) outside the doubles court on each side”; centre mark “4 inches (10 cm) in length”. The court plan in Appendix IX came back as a caption only, so it is an image: every figure here is from Rule 1’s prose.
- International Tennis Federation. Rules of Tennis, 2009 edition, © ITF Limited 2009, in the PDF published by the Iowa Games at iowagames.org/wp-content/uploads/2017/08/USTA-Rules.pdf. Read as a SECOND, INDEPENDENT copy of Rule 1 and of the tie-break procedure, so that neither the court dimensions nor the serving order rests on one fetch of one edition — which matters most for the dimensions, because the 2026 edition’s court plan came back as a caption and is therefore an image. Seventeen years apart, every figure is identical, and so are the tie-break serving order and “change ends after every six points”.
- Tennis Australia. “Dimensions”, tennis.com.au/learn/courts-and-surfaces/dimensions, citing its Tennis Infrastructure Planning Guide and the ITF Rules of Tennis. Read for the two things it adds to Rule 1: line widths of “a minimum of 2.5cm and a maximum of 5cm”, with the baseline which “may be 10cm” and the centre service line and centre mark which “shall be 5cm”; and the recommended run-off for club courts, “the space behind each baseline 5.48m (18ft)” and “the space at the sides 3.05m (10ft)”. It reproduces none of Rule 1’s own dimensions.