SizeCompass

Paper Sizes Chart

Every standard paper size — the ISO A series (A0–A10), B series and North American sizes — in millimetres, centimetres and inches.

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Quick answer

A4 = 210 × 297 mm = 8.27 × 11.69 in (21.0 × 29.7 cm). Each A size is half the previous one (A3 → two A4s) at a constant 1:√2 ratio. C sizes are the matching envelopes; US Letter (8.5 × 11 in) is the North American equivalent of A4.

ISO A series (A0–A10)

The everyday standard outside the US — A4 is the common letter/printer size.

Sizemm (w × h)cminches
A0841 × 118984.1 × 118.933.11 × 46.81
A1594 × 84159.4 × 84.123.39 × 33.11
A2420 × 59442 × 59.416.54 × 23.39
A3297 × 42029.7 × 4211.69 × 16.54
A4210 × 29721 × 29.78.27 × 11.69
A5148 × 21014.8 × 215.83 × 8.27
A6105 × 14810.5 × 14.84.13 × 5.83
A774 × 1057.4 × 10.52.91 × 4.13
A852 × 745.2 × 7.42.05 × 2.91
A937 × 523.7 × 5.21.46 × 2.05
A1026 × 372.6 × 3.71.02 × 1.46

ISO B series (B0–B8)

Used for posters, books and envelopes — sizes sit between the A series.

Sizemm (w × h)cminches
B01000 × 1414100 × 141.439.37 × 55.67
B1707 × 100070.7 × 10027.83 × 39.37
B2500 × 70750 × 70.719.69 × 27.83
B3353 × 50035.3 × 5013.9 × 19.69
B4250 × 35325 × 35.39.84 × 13.9
B5176 × 25017.6 × 256.93 × 9.84
B6125 × 17612.5 × 17.64.92 × 6.93
B788 × 1258.8 × 12.53.46 × 4.92
B862 × 886.2 × 8.82.44 × 3.46

ISO C series (envelopes)

C sizes are envelopes sized to hold the matching A-series paper — a C5 envelope fits an A4 sheet folded once.

Sizemm (w × h)inchesHolds
C0 917 × 1297 36.1 × 51.06 A0
C1 648 × 917 25.51 × 36.1 A1
C2 458 × 648 18.03 × 25.51 A2
C3 324 × 458 12.76 × 18.03 A3
C4 229 × 324 9.02 × 12.76 A4 unfolded
C5 162 × 229 6.38 × 9.02 A4 folded in half (A5)
C6 114 × 162 4.49 × 6.38 A4 folded in quarters (A6)
C7 81 × 114 3.19 × 4.49 A7
DL 110 × 220 4.33 × 8.66 A4 folded in thirds

US / North American paper sizes

Letter, Legal and Tabloid are the everyday US sizes (ANSI standard).

Sizeinches (w × h)mmcm
Letter (ANSI A) 8.5 × 11 215.9 × 279.4 21.6 × 27.9
Legal 8.5 × 14 215.9 × 355.6 21.6 × 35.6
Tabloid / Ledger (ANSI B) 11 × 17 279.4 × 431.8 27.9 × 43.2
Executive 7.25 × 10.5 184.1 × 266.7 18.4 × 26.7
Half Letter / Statement 5.5 × 8.5 139.7 × 215.9 14 × 21.6
ANSI C 17 × 22 431.8 × 558.8 43.2 × 55.9

FAQ

What is A4 size in inches?

A4 is 210 × 297 mm, which is 8.27 × 11.69 inches (about 8.3 × 11.7 in). In centimetres that's 21.0 × 29.7 cm.

What is A3 size in inches?

A3 is 297 × 420 mm — that's 11.69 × 16.54 inches, or 29.7 × 42.0 cm. A3 is exactly twice the area of A4.

How does the ISO A paper series work?

Each size is half of the one before it: fold A3 in half and you get two A4 sheets. Every size keeps the same 1:√2 (≈1.414) aspect ratio, so scaling between them never distorts the layout.

What is the difference between A4 and US Letter?

A4 (210 × 297 mm) is narrower and taller than US Letter (8.5 × 11 in = 216 × 279 mm). A4 is the ISO standard used almost everywhere except the US and Canada.

What size is A0?

A0 is 841 × 1189 mm (33.1 × 46.8 in) and has an area of exactly 1 square metre — the basis the whole A series is derived from.

Which envelope fits an A4 sheet?

A C4 envelope (229 × 324 mm) holds an unfolded A4 sheet; a C5 (162 × 229 mm) fits A4 folded once; a DL envelope (110 × 220 mm) fits A4 folded in thirds — the most common for letters.

A/B series per ISO 216; US sizes per ANSI/ASME Y14.1. Dimensions are exact standards; rounding applies to converted units.