Reference · Size guide
A1, A2, A3, A4 and A5 Paper Sizes in Inches for Artists
The A-series is the paper standard for most of the world, and it turns up on sketchbooks, watercolor pads, canvas boards and frames sold in the US. Here is the whole series in millimeters, centimeters and inches, the nearest US size for each, and what to do when an A-size drawing meets an inch-size printer or frame.
By the Austin Gallery editors · September 8, 2026
The quick answer
A4 is 8.27 x 11.69 in (21.0 x 29.7 cm), a little narrower and taller than US Letter. A3 is 11.69 x 16.54 in (29.7 x 42.0 cm), close to 12 x 16. A2 is 16.54 x 23.39 in (42.0 x 59.4 cm), close to 16 x 24. A1 is 23.39 x 33.11 in (59.4 x 84.1 cm), close to 24 x 36. A5 is 5.83 x 8.27 in (14.8 x 21.0 cm), close to 6 x 8. Each size is exactly half the one before it.
How the A-series works
The A-series is defined by ISO 216, the international standard for trimmed paper sizes. It starts from A0, a sheet with an area of one square meter and sides in the ratio 1 to the square root of 2 (1:1.414). Cut A0 in half across its long side and you get two A1 sheets with exactly the same proportions. Cut again for A2, and so on down to A8. Because the ratio never changes, a drawing made at A4 enlarges to A3 at 141 percent or reduces to A5 at 71 percent with nothing cropped, which no set of US sizes can do.
The US, Canada and a few other countries use Letter, Legal and Tabloid instead, along with the ANSI series for drawings. Everywhere else, from the UK and Europe to India, Japan and Australia, the A-series is the default, which is why art supplies made for those markets (Moleskine, Canson, Hahnemuhle, Daler-Rowney, Winsor & Newton, Arches) so often come in A sizes even when sold in the US.
A-series paper sizes in mm, cm and inches
Millimeter values are the ISO 216 definitions and are exact. Inches are the millimeters divided by 25.4, rounded to two decimals. The last column gives the nearest US paper, canvas or drawing size.
| Size | Millimeters | Centimeters | Inches | Nearest US size |
|---|---|---|---|---|
| A0 | 841 x 1189 | 84.1 x 118.9 | 33.11 x 46.81 | 36 x 48 canvas; ANSI E (34 x 44) |
| A1 | 594 x 841 | 59.4 x 84.1 | 23.39 x 33.11 | 24 x 36 canvas and poster; ANSI D (22 x 34) |
| A2 | 420 x 594 | 42.0 x 59.4 | 16.54 x 23.39 | 16 x 24 or 18 x 24; ANSI C (17 x 22) |
| A3 | 297 x 420 | 29.7 x 42.0 | 11.69 x 16.54 | 12 x 16 canvas; Tabloid (11 x 17) |
| A4 | 210 x 297 | 21.0 x 29.7 | 8.27 x 11.69 | 8 x 12 or 8 x 10 canvas; Letter (8.5 x 11) |
| A5 | 148 x 210 | 14.8 x 21.0 | 5.83 x 8.27 | 5 x 7 or 6 x 8; Half Letter (5.5 x 8.5) |
| A6 | 105 x 148 | 10.5 x 14.8 | 4.13 x 5.83 | 4 x 6 postcard |
| A7 | 74 x 105 | 7.4 x 10.5 | 2.91 x 4.13 | 3 x 4 |
| A8 | 52 x 74 | 5.2 x 7.4 | 2.05 x 2.91 | 2 x 3 (business card is 2 x 3.5) |
B-series paper sizes
The B-series sits between the A sizes: each B size is the geometric mean of the two A sizes around it, so B4 is larger than A4 and smaller than A3. B sizes are used for posters, books and some Japanese sketchbooks, and you will meet B5 (6.93 x 9.84 in) as a common notebook size and B2 and B1 as poster sizes.
| Size | Millimeters | Centimeters | Inches |
|---|---|---|---|
| B0 | 1000 x 1414 | 100.0 x 141.4 | 39.37 x 55.67 |
| B1 | 707 x 1000 | 70.7 x 100.0 | 27.83 x 39.37 |
| B2 | 500 x 707 | 50.0 x 70.7 | 19.69 x 27.83 |
| B3 | 353 x 500 | 35.3 x 50.0 | 13.90 x 19.69 |
| B4 | 250 x 353 | 25.0 x 35.3 | 9.84 x 13.90 |
| B5 | 176 x 250 | 17.6 x 25.0 | 6.93 x 9.84 |
| B6 | 125 x 176 | 12.5 x 17.6 | 4.92 x 6.93 |
| B7 | 88 x 125 | 8.8 x 12.5 | 3.46 x 4.92 |
Sketchbooks, pads and canvas boards that come in A sizes
A4 and A5 are the sketchbook sizes: Moleskine, Leuchtturm, Sakura, Stillman and Birn and most hardcover sketchbooks are A5 (pocket to bag size) or A4 (desk size). A3 is the drawing pad size: Canson, Daler-Rowney, Hahnemuhle and Maruman pads, and the most common A size for canvas boards and watercolor pads. A2 and A1 are studio pad sizes for life drawing and design work, with fewer choices and higher prices. In the US, the A3 pad occupies the same niche the 11 x 14 and 12 x 16 pads fill.
A4 sketchbook
The A4 hardcover sketchbook most artists picture when they hear the size: 96 pages of heavy plain paper, 8.27 x 11.69 inches, which lies flat and fits a laptop bag.
For a pocket size, the Sakura A5 hardcover sketchbook ($11.97) is 5.83 x 8.27 inches with 160 pages of cream paper.
A3 sketch paper
Fifty sheets of 120 gsm extra white drawing paper at A3, the standard studio drawing size in Europe. Takes pencil, charcoal and ink without buckling.
A3 watercolor pad
Arches 100 percent cotton at 140 lb (300 gsm) in the A3 size, hot press for ink and detail. The same paper as the 22 x 30 sheets, cut to the metric standard.
An A4 watercolor pad is the common size in the UK and Europe; the Canson XL Watercolour A4 pad ($19.94) is 300 gsm cold press, 30 sheets. Our best watercolor paper guide compares the cotton and cellulose papers across sizes.
A2 studio pad
Fifty sheets of 190 gsm natural white paper at A2 (16.54 x 23.39 in), the life drawing size. Heavy enough for charcoal and light washes.
A-size canvas and the nearest US canvas sizes
Canvas boards and stretched canvases in A sizes are standard in the UK, Europe, India and Australia and show up in the US through imported brands. If a tutorial or a commission calls for an A-size canvas and you can only buy inch sizes, this table gives the two closest and how far off each one is.
| A size | Inches | Nearest US canvas | Second choice |
|---|---|---|---|
| A5 | 5.83 x 8.27 | 5 x 7 (0.83 narrower, 1.27 shorter) | 6 x 8 (0.17 wider, 0.27 shorter) |
| A4 | 8.27 x 11.69 | 8 x 10 (0.27 narrower, 1.69 shorter) | 8 x 12 (0.27 narrower, 0.31 taller) |
| A3 | 11.69 x 16.54 | 12 x 16 (0.31 wider, 0.54 shorter) | 11 x 14 (0.69 narrower, 2.54 shorter) |
| A2 | 16.54 x 23.39 | 16 x 24 (0.54 narrower, 0.61 taller) | 18 x 24 (1.46 wider, 0.61 taller) |
| A1 | 23.39 x 33.11 | 24 x 36 (0.61 wider, 2.89 taller) | 24 x 32 (0.61 wider, 1.11 shorter) |
| A0 | 33.11 x 46.81 | 36 x 48 (2.89 wider, 1.19 taller) | 32 x 48 (1.11 narrower, 1.19 taller) |
The fit is tightest at A2 (16 x 24 is within 0.6 inch on both sides) and A3 (12 x 16 within 0.6 inch) and loosest at A1, where 24 x 36 is nearly 3 inches taller. For every inch size in this table, see the standard canvas sizes chart; if you need a particular shape rather than a particular size, the canvas aspect ratio guide groups the inch sizes by ratio, and every A size has the same 1:1.414 ratio (0.707), which sits between 2:3 (0.667) and 3:4 (0.75).
How A sizes frame in the US
US frame stock is in inches, and no inch frame matches an A size exactly. You have three options. Buy an A-size frame (A4 and A3 frames are now widely sold in the US). Buy the next inch frame up and have a mat cut with an A-size opening, which is the best looking result. Or buy the closest inch frame and accept a small gap. The table gives the mat route and the no-mat route for each size; more frame sizes are on our standard picture frame sizes chart.
| A size | Inch frame with a mat | Inch frame without a mat |
|---|---|---|
| A6 (4.13 x 5.83) | 5 x 7 with a mat | 4 x 6 (trim 0.13 in from width) |
| A5 (5.83 x 8.27) | 8 x 10 with a mat | 6 x 8 or 5.5 x 8.5 (nearly exact) |
| A4 (8.27 x 11.69) | 11 x 14 with a mat | 9 x 12 (0.7 in gap each side); 8.5 x 11 does not fit |
| A3 (11.69 x 16.54) | 16 x 20 with a mat | 12 x 18 (small uneven gap) |
| A2 (16.54 x 23.39) | 24 x 30 or 22 x 28 with a mat | 18 x 24 (uneven gap) |
| A1 (23.39 x 33.11) | 30 x 40 with a mat | 24 x 36 (1.4 in gap top and bottom) |
| A0 (33.11 x 46.81) | 40 x 50 with a mat | 36 x 48 (uneven gap) |
A3 frame, no mat needed
A true A3 frame at 11.7 x 16.5 inches with shatter resistant glazing, so an A3 drawing or print drops in with no mat and no gap.
The one trap is A4 in a Letter frame. A4 is 0.23 inch narrower and 0.69 inch taller than 8.5 x 11, so it does not fit a document frame without trimming the height. The reverse works: a Letter print sits in an A4 frame with the width overhanging by an eighth of an inch on each side, which a mat hides.
How A sizes print in the US
US printers and print shops default to Letter and Tabloid, so an A-size file either prints scaled or with white margins unless you set the paper size explicitly. A4 and Letter are close enough that most printers handle both; A3 needs a wide-format or 11 x 17 printer, and A2 and up go to a plotter or a print shop. The scaling factors are fixed and worth memorizing.
| Job | Scale | Why |
|---|---|---|
| A4 on Letter | 94% | Letter is 0.23 in wider and 0.69 in shorter than A4 |
| Letter on A4 | 97% | A4 is narrower, so the width sets the scale |
| A3 on Tabloid (11 x 17) | 94% | Tabloid is 0.69 in narrower and 0.46 in taller |
| Tabloid on A3 | 97% | Nearly the same size, opposite proportions |
| A4 up to A3 | 141% | Every A size is the square root of 2 times the last |
| A3 down to A4 | 71% | Every A size is 0.707 times the last |
The reason the A-series scales so cleanly is the square root of 2 ratio: doubling the area multiplies each side by 1.414, so A4 to A3 is 141 percent and A3 to A4 is 71 percent, at any size, with no cropping. US sizes do not share one ratio, so scaling Letter to Tabloid (8.5 x 11 to 11 x 17) leaves a margin on one side. If you are moving between A sizes and the watercolor fraction sizes (a quarter sheet is 11 x 15, close to A3 but not the same shape), our fraction sheet size guide lists the differences.
Frequently asked questions
What is A1 canvas size?
A1 is 594 x 841 mm, which is 59.4 x 84.1 cm or 23.39 x 33.11 inches. The nearest standard US canvas is 24 x 36 inches (61 x 91 cm), which is 0.6 inch wider and 2.9 inches taller. An A1 canvas board or stretched canvas is common in the UK, Europe, India and Australia and rare in the US.
What is A2 canvas size?
A2 is 420 x 594 mm, which is 42.0 x 59.4 cm or 16.54 x 23.39 inches. The nearest US canvas sizes are 16 x 24 (very close) and 18 x 24. An A2 sheet is exactly half of A1 and twice A3.
What is A3 canvas size?
A3 is 297 x 420 mm, which is 29.7 x 42.0 cm or 11.69 x 16.54 inches. The nearest US canvas is 12 x 16 inches, which is 0.3 inch wider and 0.5 inch shorter. A3 is the most common A size for canvas boards, sketch pads and watercolor pads.
What is A4 in inches?
A4 is 8.27 x 11.69 inches (210 x 297 mm, 21.0 x 29.7 cm). It is the everyday paper size in every country except the US, Canada and a few others, where Letter (8.5 x 11 inches) fills the same role.
Is A4 the same as Letter size?
No. A4 is 8.27 x 11.69 inches and Letter is 8.5 x 11 inches, so A4 is a quarter inch narrower and about two thirds of an inch taller. An A4 sheet does not fit an 8.5 x 11 frame or document frame without trimming, and a Letter document printed on A4 needs to scale to 97 percent.
Which is bigger, A3 or 11 x 14?
A3 is bigger. A3 is 11.69 x 16.54 inches; 11 x 14 is 0.69 inch narrower and 2.54 inches shorter. The US size closest to A3 is 12 x 16, and the closest common frame is 12 x 18 or a 16 x 20 with a mat.
How do the A sizes relate to each other?
Each A size is half the one before it, cut across the long side, and every size has the same proportions, 1 to the square root of 2 (about 1:1.414). A0 has an area of one square meter. That constant ratio is why a drawing scales from A4 to A3 at 141 percent with nothing cropped, which is not true of US sizes.
What size frame fits an A4 or A3 print in the US?
For A4, an 11 x 14 frame with a mat cut to an 8.27 x 11.69 opening, or a 9 x 12 frame without a mat. For A3, a 16 x 20 frame with a mat, or a 12 x 18 frame without one. A-size frames are also sold in the US now, and an A3 or A4 frame is the simplest answer if you plan to frame more than one.
Size guides