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Paper size lookup
Pick a size for its dimensions and area — or enter a width and height in millimetres to identify the size.
★ REFERENCE CHART · EVERYDAY · PAPER
Standard Paper Size Chart: A4, Letter & Legal 2026
A4 is 210×297 mm — 8.27×11.69 in, 21.0×29.7 cm, 623.70 cm² — and Letter is 8.5×11 in. Every standard size is in the table below, with millimetres, inches, centimetres, area and what each size is used for — pick a size in the calculator, or enter a width in millimetres and the reverse lookup names the size.
The full chart
Every standard paper size: millimetres, inches, centimetres, area and the ratio of height to width. The A-series sizes halve neatly — fold an A3 in half and you get two A4 sheets — while the North American sizes (Letter, Legal, Tabloid) are their own system. Inches for Letter, Legal and Tabloid are the nominal sizes printed on the pack (8.5×11, 8.5×14, 11×17), not the millimetres divided by 25.4 — which would give 10.98, 14.02 and 17.01 inches.
| Size | Millimetres | Inches | Centimetres | Area | Ratio | Used for |
|---|---|---|---|---|---|---|
| A2 | 420×594 mm | 16.54×23.39 in | 42.0×59.4 cm | 2,494.80 cm² | 1.41 | Posters and large prints |
| A3 | 297×420 mm | 11.69×16.54 in | 29.7×42.0 cm | 1,247.40 cm² | 1.41 | Posters, charts and spreadsheets |
| A4 | 210×297 mm | 8.27×11.69 in | 21.0×29.7 cm | 623.70 cm² | 1.41 | Letters, documents and printing |
| A5 | 148×210 mm | 5.83×8.27 in | 14.8×21.0 cm | 310.80 cm² | 1.42 | Notebooks, flyers and booklets |
| A6 | 105×148 mm | 4.13×5.83 in | 10.5×14.8 cm | 155.40 cm² | 1.41 | Postcards and small flyers |
| Letter | 216×279 mm | 8.5×11 in | 21.6×27.9 cm | 602.64 cm² | 1.29 | US letters and documents |
| Legal | 216×356 mm | 8.5×14 in | 21.6×35.6 cm | 768.96 cm² | 1.65 | US legal documents and contracts |
| Tabloid | 279×432 mm | 11×17 in | 27.9×43.2 cm | 1,205.28 cm² | 1.55 | US newspapers and large spreads |
The worked example, line by line
Defaults: paper size A4.
Line 1 — the millimetres. A4 is 210×297 mm — the size printed on the ream.
Line 2 — the inches. 210 ÷ 25.4 = 8.27 in wide; 297 ÷ 25.4 = 11.69 in tall. A4 is a touch narrower and a touch taller than US Letter.
Line 3 — the centimetres. 210 ÷ 10 = 21.0 cm wide; 297 ÷ 10 = 29.7 cm tall.
Line 4 — the area. 21.0 × 29.7 = 623.70 cm².
Line 5 — the ratio. 297 ÷ 210 = 1.41 — the A-series ratio, the square root of 2, which is why halving the sheet keeps the same shape.
Reverse: a sheet 210 mm wide and 297 mm tall is A4; 105 mm wide is A6; 148 mm wide is A5; 216 mm wide is Letter at 279 mm tall and Legal at 356 mm tall; 279 mm wide is Tabloid; 297 mm wide is A3; 420 mm wide is A2.
Every branch, checked
A3: 297×420 mm, 11.69×16.54 in, 29.7×42.0 cm, 1,247.40 cm², ratio 1.41. One A3 is exactly 2× one A4 — two A4 sheets side by side.
A5: 148×210 mm, 5.83×8.27 in, 14.8×21.0 cm, 310.80 cm², ratio 1.42. Half an A4 by definition — from the rounded millimetre sizes one A4 is 2.01× one A5 and 4.01× one A6.
Letter: 216×279 mm, 8.5×11 in, 21.6×27.9 cm, 602.64 cm², ratio 1.29. A4 is 1.03× Letter by area (623.70 ÷ 602.64) — close, but not the same sheet, so a Letter printer tray will not take A4 cleanly.
Legal: 216×356 mm, 8.5×14 in, 21.6×35.6 cm, 768.96 cm², ratio 1.65. Legal is 1.28× Letter by area (768.96 ÷ 602.64) — the same width, three inches longer.
Tabloid: 279×432 mm, 11×17 in, 27.9×43.2 cm, 1,205.28 cm², ratio 1.55. Two Letter sheets side by side — the US newspaper size.
Output · formula · meaning
| Output | Formula | What it means |
|---|---|---|
| Millimetres | table row | 210×297 mm for A4. |
| Inches | mm ÷ 25.4 (A-series); nominal (US sizes) | 8.27×11.69 in for A4. |
| Centimetres | mm ÷ 10 | 21.0×29.7 cm for A4. |
| Area | cm width × cm height | 623.70 cm² for A4. |
| Ratio | height ÷ width | 1.41 for A4. |
| A3 | table row | 297×420 mm, 11.69×16.54 in, 1,247.40 cm². |
| A5 | table row | 148×210 mm, 5.83×8.27 in, 310.80 cm². |
| Letter | table row | 216×279 mm, 8.5×11 in, 602.64 cm². |
| Legal | table row | 216×356 mm, 8.5×14 in, 768.96 cm². |
| Tabloid | table row | 279×432 mm, 11×17 in, 1,205.28 cm². |
| Reverse: 105 mm wide | nearest by width | A6. |
| Reverse: 148 mm wide | nearest by width | A5. |
| Reverse: 210 mm wide | nearest by width | A4. |
| Reverse: 216 mm wide | width + height decide | Letter or Legal. |
| Reverse: 279 mm wide | nearest by width | Tabloid. |
| Reverse: 297 mm wide | nearest by width | A3. |
| Reverse: 420 mm wide | nearest by width | A2. |
| One A3 = 2× one A4 | area ÷ area | 1,247.40 ÷ 623.70 = 2.00. |
| One A4 vs one A5 / one A6 | area ÷ area | 623.70 ÷ 310.80 = 2.01; 623.70 ÷ 155.40 = 4.01. |
| A4 vs Letter area | 623.70 ÷ 602.64 | 1.03×. |
| Legal vs Letter area | 768.96 ÷ 602.64 | 1.28×. |
Who uses this
- The office worker printing a document: they learn A4 is 210×297 mm and 623.70 cm² — so they know the paper in the tray, and they check the 8.27×11.69 in against a US Letter printer before sending the file.
- The designer laying out a poster: they learn A3 is 297×420 mm and exactly 2× one A4 — so they know the poster is two A4 sheets, and they check the A2 row at 420×594 mm before going bigger.
- The US reader with a metric sheet: they learn Letter is 216×279 mm and 8.5×11 in — so they know their paper is a touch shorter and wider than A4, and they check the Legal row at 8.5×14 in before printing a contract.
- The measurer with a ruler: they learn a 210 mm wide sheet is A4 and a 216 mm wide sheet is Letter or Legal — so they can name any sheet from its width, and they check the height (279 mm is Letter, 356 mm is Legal) when the width alone is not enough.
Accuracy & limitations
The sizes are the ISO 216 A-series and the North American standard sizes: A2, A3, A4, A5 and A6 follow the root-2 ratio, so each size is half the one above it, and Letter, Legal and Tabloid are the US standards. The A-series ratio is the square root of 2, about 1.41 — A5 rounds to 1.42 because 210 ÷ 148 is 1.4189. Inches for Letter, Legal and Tabloid are the nominal sizes on the pack, not the millimetres divided by 25.4. Real paper varies by a millimetre or two with the maker and with humidity, and a printer set to the wrong size will scale the page — always check the tray setting before printing. This is not a paper-weight or GSM chart and not an envelope chart: weight and envelope sizes are separate lookups. For envelope sizes, see envelope size chart; for converting between units, see celsius to fahrenheit chart.
Cite this reference tableBright Side Kit. “Standard Paper Size Chart: A4, Letter & Legal 2026.” brightoolbox.com, 2026. Method: area = cm width × cm height; ratio = height ÷ width; A-series inches = mm ÷ 25.4; Letter, Legal and Tabloid inches are the nominal sizes (8.5×11, 8.5×14, 11×17), not computed from millimetres. Defaults: A4 → 210×297 mm, 8.27×11.69 in, 21.0×29.7 cm, 623.70 cm², ratio 1.41. Rows: A2 → 420×594 mm, 16.54×23.39 in, 42.0×59.4 cm, 2,494.80 cm², ratio 1.41; A3 → 297×420 mm, 11.69×16.54 in, 29.7×42.0 cm, 1,247.40 cm², ratio 1.41; A4 → 210×297 mm, 8.27×11.69 in, 21.0×29.7 cm, 623.70 cm², ratio 1.41; A5 → 148×210 mm, 5.83×8.27 in, 14.8×21.0 cm, 310.80 cm², ratio 1.42; A6 → 105×148 mm, 4.13×5.83 in, 10.5×14.8 cm, 155.40 cm², ratio 1.41; Letter → 216×279 mm, 8.5×11 in, 21.6×27.9 cm, 602.64 cm², ratio 1.29; Legal → 216×356 mm, 8.5×14 in, 21.6×35.6 cm, 768.96 cm², ratio 1.65; Tabloid → 279×432 mm, 11×17 in, 27.9×43.2 cm, 1,205.28 cm², ratio 1.55. Reverses: 105 mm → A6; 148 mm → A5; 210 mm → A4; 216 mm → Letter or Legal (height decides: 279 mm tall is Letter, 356 mm tall is Legal); 279 mm → Tabloid; 297 mm → A3; 420 mm → A2. Extras: one A3 = 2× one A4 (exact); one A4 is about 2× one A5 (2.01×) and about 4× one A6 (4.01×) from the rounded sizes; A4 is 1.03× Letter area; Legal is 1.28× Letter area. This is not a paper-weight/GSM or envelope chart.
Bright Side Kit. "Standard Paper Size Chart: A4, Letter & Legal 2026." https://brightoolbox.com/paper-size-chart/ Accessed October 25, 2026.Frequently asked questions
What size is A4 paper?
A4 is 210×297 mm — 8.27×11.69 in, 21.0×29.7 cm, 623.70 cm², ratio 1.41. It is the standard office paper in most of the world outside the US and Canada.
Is A4 bigger than Letter?
Yes, slightly. A4 is 623.70 cm² against 602.64 cm² for Letter — A4 is 1.03× Letter by area. A4 is narrower (210 mm against 216 mm) but taller (297 mm against 279 mm), so the two are not interchangeable in a printer tray.
What is the biggest size in the chart?
A2 — 420×594 mm, 16.54×23.39 in, 42.0×59.4 cm, 2,494.80 cm². It is four times one A4 sheet and is used for posters and large prints.
What size is Legal paper?
Legal is 216×356 mm — 8.5×14 in, 21.6×35.6 cm, 768.96 cm², ratio 1.65. It is the same width as Letter but three inches longer, and 1.28× Letter by area.
What size is Tabloid paper?
Tabloid is 279×432 mm — 11×17 in, 27.9×43.2 cm, 1,205.28 cm², ratio 1.55. It is two Letter sheets side by side and is the US newspaper size.
How do I find a paper size from a width in millimetres?
Enter the width and height in the calculator above. A sheet 105 mm wide is A6, 148 mm is A5, 210 mm is A4, 279 mm is Tabloid, 297 mm is A3 and 420 mm is A2. A sheet 216 mm wide is Letter or Legal — the height decides: 279 mm tall is Letter, 356 mm tall is Legal.
How many A5 sheets fit in one A4 sheet?
Two — by definition one A4 is two A5 sheets, and one A3 is two A4 sheets. From the rounded millimetre sizes the areas work out at 2.01× and 4.01×. The A-series halves neatly because the ratio is the square root of 2, so folding keeps the same shape.
Does this chart cover paper weight or envelopes?
No. This is a size chart only — it is not a paper-weight or GSM chart, and it is not an envelope chart. For envelope sizes, see the envelope size chart.