Close-viewed detail
A strong target for photo prints, fine text, and posters people may inspect from arm's length.
Print DPI Calculator for Posters
Use this print DPI calculator to check image resolution at the finished size—not just the DPI tag stored in the file. Upload locally, choose a paper or tiled poster size, and see effective PPI, maximum print size, required pixels, and viewing distance.
Paper size
Plan a Rasterbator poster
Choose the sheet size and poster width in sheets. We calculate the finished tiled dimensions, effective PPI, pixel targets, and viewing distance with the same sizing engine as the poster maker.
The image stays in your browser. If you continue, the same local file is carried into the poster maker.
Rasterbator poster
4 × 2 sheets
Finished poster size
110.8 × 73.9 cm (43.6 × 29.1 in)
Effective image resolution
69 PPI across the finished tiled poster.
Pixel targets for this poster
150 PPI: 6,544 × 4,363 px
300 PPI: 13,087 × 8,725 px
Viewing distance
At this size, the image reaches the one-arcminute optical threshold from about 1.3 m away. Halftone output is often forgiving at normal wall-viewing distance.
Paper margins and automatic row count use the exact same sizing function as the Rasterbator poster maker.
Open the poster maker →Print DPI calculator for poster viewing distance
A poster viewed across a room does not need the same pixel density as a photo held in your hand. Move the slider to compare your effective resolution with an optical-distance reference.
At 1 m viewing: about 87 DPI is the optical minimum.
Halftone posters can tolerate lower effective DPI because the dot pattern masks ordinary pixelation from normal wall-viewing distances. For very large work, judge quality from where people will actually stand.
Print resolution guide
What is the best DPI for printing a poster?
The best DPI for printing depends on how large the poster is and how far away it will be viewed. For source images, compare effective PPI with the finished physical size rather than treating 300 as a universal rule.
Typical wall poster
A practical target for many wall posters viewed from roughly a metre or more.
Large tiled poster
For oversized Rasterbator output, compare effective PPI with the viewing-distance result instead of forcing every poster to 300 PPI.
Poster size calculator reference
Common poster sizes in pixels
These are source-image targets for the finished print. For a multi-sheet Rasterbator poster, use the assembled poster dimensions—the first tab calculates those exact targets for your current layout.
| Finished size | 150 PPI | 300 PPI |
|---|---|---|
| A3 | 1,754 × 2,481 px | 3,508 × 4,961 px |
| 12 × 18 in | 1,800 × 2,700 px | 3,600 × 5,400 px |
| 16 × 20 in | 2,400 × 3,000 px | 4,800 × 6,000 px |
| 18 × 24 in | 2,700 × 3,600 px | 5,400 × 7,200 px |
| 24 × 36 in | 3,600 × 5,400 px | 7,200 × 10,800 px |
People often say “poster DPI,” but source-image sizing is more precisely PPI. The calculator uses pixel dimensions and finished inches, while your printer can have a separate hardware DPI.
DPI vs PPI for printing: pixels per inch explained
PPI means pixels per inch. This page works as a PPI calculator for print planning: divide the source pixels by the finished size in inches on each axis, then use the lower value as the effective image resolution. DPI, by contrast, can describe the physical dots produced by a printer.
An image DPI tag does not create detail. A 3000-pixel-wide file still contains 3000 pixels whether its metadata says 72 DPI or 300 DPI. For image resolution for printing, the finished size determines how densely those pixels are spread across the poster.
Print DPI & PPI FAQ
What does a PPI calculator tell me before I print?
PPI means pixels per inch. For print planning, this calculator divides the source pixels by the finished size in inches on both axes and uses the lower result as the effective image resolution.
How do I find the pixels per inch of an image at a chosen print size?
Divide the image width in pixels by the finished width in inches, then repeat for height. The smaller value is the limiting PPI, because that axis will run out of pixels first.
Can I use this as an image resolution checker before printing?
Yes. Upload an image or enter its pixel dimensions, choose the finished print size, and the page checks effective PPI locally. In that practical print sense it also works as an image DPI checker without relying only on the DPI tag stored in the file.
What is the best DPI for printing a poster?
For source images, think in PPI: around 300 PPI is a strong target for close viewing, while about 150 PPI is often sufficient for wall posters. Oversized posters can work at lower values when the viewing distance is longer.
Is 150 or 300 DPI better for a large poster?
Choose 300 PPI when fine detail will be inspected nearby. For a large wall poster viewed from farther back, 150 PPI can be a practical target; use the viewing-distance result instead of assuming every poster needs 300.
How many pixels should a 24 × 36 inch poster have?
For a 24 × 36 inch print, 3,600 × 5,400 pixels reaches 150 PPI. Doubling each axis to 7,200 × 10,800 pixels reaches 300 PPI.
Is 300 PPI the same as 300 DPI?
Not exactly. PPI describes how image pixels are distributed across the finished print; printer DPI describes physical output dots. They are often used interchangeably in casual print instructions, but they measure different things.
Can a 72 PPI image work for a wall poster?
Sometimes. The answer depends on the finished poster size and viewing distance, not the metadata value alone. Check the actual pixel dimensions against the final assembled size.
How should I check resolution for a tiled Rasterbator poster?
Judge the full assembled poster, not one sheet. This page uses the same poster-sizing engine as the poster maker, so its effective PPI is based on the finished multi-page dimensions.
Do halftone posters need very high resolution?
Not always. A deliberate dot pattern and normal wall-viewing distance can make lower effective PPI more forgiving than a close-viewed photo print.
Turn the resolution check into a printable poster
Carry the same local image and sheet settings into the Rasterbator poster maker, generate the tiled PDF, and choose a halftone or raster style when a large wall-viewed poster benefits from a coarser treatment.