Chess board sizes in centimetres: a metric guide
Square sizes in mm, the king height and base that fit each one, FIDE's 5–6 cm and 9.5 cm figures, and how to work out a board's overall size in cm.
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Most chess equipment advice online is written in inches, because a lot of it comes from US sellers. If you shop in Europe, the UK, Australia or almost anywhere else, listings will usually give square sizes in millimetres or centimetres instead, and converting back and forth gets old quickly. This guide does the whole job in metric.
If you prefer inches, the same rules are in our inch-based size guide.
The two rules that decide fit
You only need two ratios to match pieces to a board.
- King base to square. The king’s base should cover roughly 75–80% of the width of a square. A common midpoint is 78%. Much below that and the pieces look lost; much above and the board feels crowded.
- King base to king height. FIDE says every piece’s base diameter should be 40–50% of its height. This keeps pieces stable and in proportion.
Put together, a square of a given size points to a king base, and the king base points to a sensible range of king heights.
The FIDE numbers in metric
FIDE’s equipment standards are written in metric, so no conversion is needed. The current version applies from 1 March 2026.
| Item | FIDE figure |
|---|---|
| Square size | 5–6 cm per side |
| Pawn fit | Four pawns should fit comfortably on one square |
| King height | 95 mm (other pieces scale down from there) |
| Height tolerance | Up to ±10%, keeping the order of heights |
| Base diameter | 40–50% of each piece’s height |
| Board finish | Matte or non-reflective; light squares white, cream, ivory or buff, dark squares brown or walnut tone |
| Table height | 74 cm (±10%) |
| Table size | About 110 × 85 cm (±15%) |
FIDE’s recommended heights for the other pieces are queen 85 mm, bishop 70 mm, knight 60 mm, rook 55 mm and pawn 50 mm.
A little arithmetic shows how these fit together. With the ±10% tolerance, a FIDE king can be anywhere from about 85.5 mm to 104.5 mm tall. A 95 mm king with a base of 40–50% of its height has a base of 38–47.5 mm. At the 78% ratio, that base suits a square of roughly 49–61 mm, which lands neatly on FIDE’s 5–6 cm range.
Metric sizing table
Each row below is calculated from the two rules above: ideal king base = 78% of the square, and king height = base ÷ 0.5 (shortest) to base ÷ 0.4 (tallest). Figures are rounded. Real sets vary, so always check the king base in the listing.
| Square size | Approx. in inches | Ideal king base | King height that fits | Playing area (8 × square) |
|---|---|---|---|---|
| 35 mm | 1.38” | about 27 mm | 55–68 mm | 28 cm |
| 40 mm | 1.57” | about 31 mm | 62–78 mm | 32 cm |
| 45 mm | 1.77” | about 35 mm | 70–88 mm | 36 cm |
| 50 mm | 1.97” | about 39 mm | 78–98 mm | 40 cm |
| 55 mm | 2.17” | about 43 mm | 86–107 mm | 44 cm |
| 57 mm | 2.24” | about 44.5 mm | 89–111 mm | 45.6 cm |
| 60 mm | 2.36” | about 47 mm | 94–117 mm | 48 cm |
A few notes on reading it:
- 57 mm is the metric name for the US 2.25” square (2.25 × 25.4 = 57.15 mm). If you see a European listing for 57 mm squares, it is the familiar club size.
- 50–60 mm is tournament territory. That’s the FIDE range, and the rows where a 95 mm king fits comfortably.
- 35–45 mm is home, travel and children’s territory. Larger folding sets sit here, and many magnetic travel sets are smaller still; see our travel chess set guide.
How big is the whole board?
The overall size is simple:
Overall board = (8 × square size) + (2 × border width)
The playing area is always eight squares across. The border is up to the maker, and FIDE doesn’t set one. A border is where coordinates (a–h, 1–8) are usually printed.
Some worked examples:
| Square | Playing area | With 2 cm border each side | With 3 cm border each side |
|---|---|---|---|
| 40 mm | 32 cm | 36 cm | 38 cm |
| 50 mm | 40 cm | 44 cm | 46 cm |
| 55 mm | 44 cm | 48 cm | 50 cm |
| 57 mm | 45.6 cm | 49.6 cm | 51.6 cm |
| 60 mm | 48 cm | 52 cm | 54 cm |
This works in reverse too. If a listing only gives the overall size, subtract both borders and divide by eight to get the square size. A 50 cm board with 3 cm borders has a 44 cm playing area, so 55 mm squares.
Before buying a big board, measure your table. A 50 cm board takes up a lot of a small café or coffee table once you add a clock and two sets of elbows. FIDE’s tournament table is about 110 × 85 cm for a reason.
Reading metric listings
Sellers describe size in different ways, and it’s easy to compare the wrong numbers.
- A board named by one size (“45 cm board”) is often giving the overall board, border included, not the square. Look for a separate square measurement.
- King height is the number most listings give for pieces. King base is the one you actually need for fit. If the base isn’t listed, work it out: base should be 40–50% of height, so a 95 mm king will have a base somewhere around 38–48 mm.
- Inch figures turn up in European listings too. Multiply inches by 2.54 for centimetres, or by 25.4 for millimetres. A 3.75” king is about 95 mm, which is why it is so often paired with 57 mm squares.
Which size should you buy?
- Club and tournament play: 50–57 mm squares with a king around 90–98 mm. Browse tournament chess sets at Chess House or search tournament sets on Amazon.
- Home play: 45–50 mm squares with a king around 75–90 mm is comfortable on most tables.
- Display and heirloom sets: 55–60 mm squares, since large luxury kings need the room. Browse wooden chess boards at Chess House or search wooden boards with 55 mm squares.
- Travel and young children: 30–40 mm squares, usually on magnetic or folding boards.
If you’re buying pieces and board separately, write down three numbers before you order: square size in mm, king height in mm and king base in mm. Then check the base is about 78% of the square. For help with the rest of the decision, see how to choose a chess board and our tournament chess board guide.