What is A3 at 300 PPI?

A3 in portrait orientation is 3508 × 4961 pixels at 300 PPI. Landscape uses the same two values in reverse order.

What aspect ratio is A3?

A3 uses a 1:√2 aspect ratio. An image with a different ratio must be cropped, fitted with borders or placed inside the page.

Does the A3 pixel size include bleed?

No. The table uses final trim dimensions. Add the exact bleed required by the printer to both sides before calculating the full artwork canvas.

How many pixels does an A3 poster need?

For the 297 × 420 mm trim, A3 needs 1754 × 2480 px at 150 PPI, 2806 × 3969 px at 240 PPI or 3508 × 4961 px at 300 PPI. Add bleed separately when required.

ISO size reference

A3 Size in Pixels and Print Dimensions

A3 paper measures 297 × 420 mm. Its pixel dimensions change with PPI; the physical trim size does not.

Quick answer

A3 measures exactly 297 × 420 mm (29.7 × 42 cm), or approximately 11.69 × 16.54 inches. At 300 PPI, portrait A3 rounds to 3508 × 4961 pixels.

300 PPI: 3508 × 4961 px · ISO 216 trim

Pixel table

A3 pixels by PPI

Portrait values are rounded to the nearest whole pixel after converting the native physical dimensions.

PPI	Width	Height	Use context
72	842 px	1191 px	Layout or screen reference
96	1123 px	1587 px	Layout or screen reference
150	1754 px	2480 px	Print / distance dependent
240	2806 px	3969 px	Print / distance dependent
300	3508 px	4961 px	Detailed print target
600	7016 px	9921 px	Detailed print target

Poster planning

Choose PPI for the real viewing distance

A3 is 1754 × 2480 px at 150 PPI, 2806 × 3969 px at 240 PPI and 3508 × 4961 px at 300 PPI. Confirm the target with the print provider.

Check an actual image →

A3 vs A4

A3 has twice the area of A4

Folding A3 in half along its long edge produces A4. Both formats keep the ISO 1:√2 aspect ratio, so layouts can scale proportionally.

Compare A4 →

Bleed example

A3 with 3 mm bleed

Adding 3 mm on every edge creates a 303 × 426 mm artwork canvas, which rounds to 3579 × 5031 pixels at 300 PPI.

Calculate another margin →

Change the resolution

Calculate A3 at any PPI.

Interactive calculator

pixels = millimetres ÷ 25.4 × PPI

Paper preset → pixel dimensions

Print preset

Target PPI

PPI

Quick targets

Calculated resultsUpdates as you change the inputs

A3 pixel dimensionsPrimary result

3508 × 4961 px

Trim sizeResult

297 × 420 mm

Trim size in inchesResult

11.69 × 16.54 in

A3 at common targets

Target	Width	Height
150 PPI	1754 px	2480 px
240 PPI	2806 px	3969 px
300 PPI	3508 px	4961 px

Print setup

Trim first. Add production values second.

A3 identifies the final physical format. Bleed expands the artwork beyond that edge; a safe margin moves important content inward. Those extra values depend on the print provider.

Calculate bleed and safe area →

Check before you print

Use the image, not a guess.

Run the source pixels against the exact size you plan to order.

Check an image →