Paper size calculator

What size is A4 paper in inches?

A4 is 210 × 297 millimeters, which is 8.27 × 11.69 inches (about 8.27 × 11.69). US Letter is 8.5 × 11 inches, or 215.9 × 279.4 millimeters.

What is the difference between A4 and US Letter?

Letter is 5.9 mm wider than A4 and 17.6 mm shorter. A4 is long and narrow, Letter short and wide. A document laid out for one has to be scaled or re-flowed to fit the other: A4 printed on Letter at "fit to page" shrinks to about 94%, and a Letter page printed on A4 shrinks to about 97%.

Why do A-series sheets keep their shape when folded in half?

Every ISO sheet has sides in the ratio 1 to the square root of 2 (1.414). Cut such a sheet across its long side and each half has the same ratio. A0 is defined as one square meter, so A1 is half a square meter, and so on down to A10. A4 is 210 × 297, and its ratio is 1.414.

What are the B and C series for?

The B series fills the gaps between A sizes for posters and books: the short side of B0 is exactly one meter. The C series is mostly for envelopes, sized so that the A size of the same number fits inside: an A4 sheet goes unfolded into a C4 envelope (229 × 324 mm), folded once into C5.

Is Ledger the same as Tabloid?

They are the same dimensions, 11 × 17 inches (279.4 × 431.8 mm), used in two orientations. Tabloid is usually 11 wide by 17 tall, Ledger 17 wide by 11 tall. ANSI B is the same sheet in engineering drawings.

What are ANSI paper sizes?

ANSI/ASME Y14.1 defines the sheet sizes for engineering drawings in the United States: A is Letter (8.5 × 11 in), B is 11 × 17, C is 17 × 22, D is 22 × 34 and E is 34 × 44 inches. Each is made by doubling the previous one. The Arch series for architects (Arch A 9 × 12 in up to Arch E 36 × 48 in) is part of the same standard.

Which countries use which?

ISO 216 is used in nearly every country outside North America, while the Philippines and parts of Latin America also use Letter-based sizes. If you send documents abroad, assume the recipient prints on A4 when in Europe, Africa, Asia or Oceania, and on Letter in the United States and Canada.

How the ISO sizes are built

Start with A0, one square meter with sides in the ratio 1 : 1.414, rounded to whole millimeters: 841 × 1189. Halve the long side and round down to get the next size, so A1 is 594 × 841, A2 is 420 × 594, and A4 is 210 × 297. Each step halves the area. B sizes are the geometric mean of two neighboring A sizes, and C sizes the geometric mean of A and B. ISO 216 allows a tolerance of ±1.5 mm for sides up to 150 mm, ±2 mm up to 600 mm and ±3 mm above that, so two A4 sheets from different mills can differ by a millimeter.

How the North American sizes are built

Letter (8.5 × 11 in) has a ratio of 1.294, Legal (8.5 × 14) is 1.647 and Ledger (11 × 17) is 1.545, so no halving keeps the shape the way A4 to A5 does. The ANSI series doubles an area while alternating between two ratios: cutting a Ledger sheet in half across the long side gives two Letter sheets, but the proportions change from 1.545 to 1.294. Sizes in inches are exact, and the millimeter values here convert at 25.4 mm per inch.

Worked example

Your design is for Letter and the printer has A4. The page widths are 215.9 and 210 mm, the heights 279.4 and 297 mm. Letter is 5.9 mm wider than A4 so it does not fit at full size; reducing it to 97% fits width and height and leaves a strip about 25.2 mm tall at the foot of the A4 sheet. Now cutting: one A3 sheet yields 2 A4 sheets and one A0 yields 16 (A5 is half of A4, 148 × 210). One Ledger sheet yields 2 Letter sheets, but an A3 sheet gives just 1 Letter sheet, because Letter is too wide to fit twice across 297 mm. Finally, a sheet that measures 215 × 280 mm is Letter (215.9 × 279.4), within 0.9 mm.

Common mistakes

Ordering by name instead of dimensions: B4 is not a larger A4, it is 250 × 353 mm, between A3 and A4. Mixing width and height: sizes here are written width × height in portrait. Forgetting bleed and margins: a print shop asks for extra image beyond the trim line (the bleed; the amount is in its specification), and most home printers cannot print to the edge, so a full-bleed A4 design is normally printed on a larger sheet and trimmed. Treating Tabloid and Ledger as different sheets. And assuming a roll, canvas or photo paper follows these tables: photo and frame sizes such as 4 × 6 and 8 × 10 inches are separate conventions.

Sources and related calculators

Sources: ISO 216 (A, B and C series; dimensions and tolerances as published in the ISO 216 summary on Wikipedia, since the standard itself is sold, not free); ANSI/ASME Y14.1 for the ANSI and Arch sheets and the common North American sizes as listed in the Wikipedia article “Paper size”. One inch is exactly 25.4 mm. Related: print size calculator, aspect ratio calculator, ring size calculator and TV size calculator.