The resolution for printing photos comes down to one number: how many of the image's pixels land on each inch of paper. About 300 is the target for prints people hold in their hands, and less works for prints they stand back from. Below are the pixel sizes for common photo, paper and poster sizes, what DPI actually measures, and how to check whether a file is big enough before you pay for the print.
What resolution for printing photos at each size
Take each side in inches and multiply it by the pixels per inch (PPI) you're aiming for. An 8 x 10 print at 300 PPI needs 8 x 300 = 2400 pixels by 10 x 300 = 3000 pixels. To go the other way, divide: a file 3000 pixels wide prints 10 inches wide at 300 PPI.
| Print size (inches) | Common use | Pixels at 300 PPI | Pixels at 200 PPI | Pixels at 150 PPI |
|---|---|---|---|---|
| 4 x 6 | Photo prints, postcards | 1200 x 1800 | 800 x 1200 | 600 x 900 |
| 5 x 7 | Framed photos, cards | 1500 x 2100 | 1000 x 1400 | 750 x 1050 |
| 8 x 10 | Framed prints | 2400 x 3000 | 1600 x 2000 | 1200 x 1500 |
| 8.5 x 11 (US Letter) | Flyers, home printing | 2550 x 3300 | 1700 x 2200 | 1275 x 1650 |
| 8.27 x 11.69 (A4) | Flyers and documents outside North America | 2480 x 3508 | 1654 x 2339 | 1240 x 1754 |
| 11 x 14 | Wall frames | 3300 x 4200 | 2200 x 2800 | 1650 x 2100 |
| 11 x 17 (Tabloid) | Small posters | 3300 x 5100 | 2200 x 3400 | 1650 x 2550 |
| 16 x 20 | Large frames | 4800 x 6000 | 3200 x 4000 | 2400 x 3000 |
| 18 x 24 | Posters | 5400 x 7200 | 3600 x 4800 | 2700 x 3600 |
| 24 x 36 | Large posters | 7200 x 10800 | 4800 x 7200 | 3600 x 5400 |
Use the 300 PPI column for anything held in the hand or framed at eye level, and the 150 PPI column only for posters and signs seen from a few steps back.
What is DPI?
DPI means dots per inch: the number of ink dots a printer places across one inch of paper. PPI, pixels per inch, is the matching number for an image file: how many of its pixels are spread across each printed inch. 4OVER4, a commercial printer, notes that people often mix the two up and that for setting up a file they mean the same thing. When a shop asks for "300 DPI", it wants a file with enough pixels to put 300 of them on every inch of the finished print.
What is DPI resolution on a printer?
A printer's DPI describes the machine, not your photo. Adobe says most inkjet printers run at 720 to 2880 dpi, and that this is separate from image resolution. A printer builds each color out of many tiny dots, which is why its dot count is far higher than the pixels per inch a photo needs. A 2880 dpi printer does not need a 2880 PPI file.
What is DPI in an image?
The DPI or PPI value saved inside an image file is only a label for print size. Changing it doesn't add or remove a single pixel. Adobe explains that raising the resolution without resampling shrinks the printed size by the same factor, and lowering it enlarges the print. A 3000 x 2400 pixel file prints 10 x 8 inches at 300 PPI or 41.7 x 33.3 inches at 72 PPI, from exactly the same pixels. So a file that says 72 DPI isn't necessarily low resolution. Count its pixels instead.
Why 300 PPI, and when less is fine
Adobe calls 300 PPI the industry standard for high-quality prints, because images look sharp at that resolution even up close. The required number drops as the viewer moves back, since fine detail stops being visible. 4OVER4's rule of thumb is that doubling the viewing distance roughly halves the resolution a print needs.
| What you're printing | How far away people look | Aim for | Source of the guidance |
|---|---|---|---|
| Photos, cards, flyers | Arm's length or closer | 300 PPI | Adobe, 4OVER4 |
| Inkjet photo prints at home | Arm's length | 220 PPI or more | Adobe |
| Posters | 3 to 5 feet | 150 to 200 PPI | 4OVER4 |
| Banners and signs | Across a room or street | 100 to 150 PPI | 4OVER4 |
| Fine line art, not photos | Close | 600 to 1200 PPI, or keep it as vector art | 4OVER4 |
Going above 300 PPI for a photo mostly makes the file larger. 4OVER4 notes that a photo printed once at 300 and once at 600 on identical paper can't be told apart, because the printing process can't reproduce the extra detail.
What resolution for printing posters
Posters can run at 150 to 200 PPI because nobody reads them from six inches away. An 11 x 17 poster needs 1650 x 2550 pixels at 150 PPI, an 18 x 24 needs 2700 x 3600, and a 24 x 36 needs 3600 x 5400. If the poster will hang in a hallway where people stop and read small print, such as a class schedule, use the 200 PPI column instead.
The shape matters as much as the pixel count. An 18 x 24 poster is exactly 3:4, so a 4032 x 3024 pixel phone photo (12 megapixels) fills it at 168 PPI with nothing cut off. A 24 x 36 poster is 2:3, a longer shape, so the same photo has to be cropped to 4032 x 2688 first. Spread over 36 inches, that's about 112 PPI, below the 150 PPI poster guideline, so it will look soft up close. Check the print shop's file guide for its own minimum before you order. For print shop options, see where to print flyers and posters.
What resolution for printing A4
A4 is 210 x 297 mm, or 8.27 x 11.69 inches, so an A4 page at 300 PPI needs 2480 x 3508 pixels. A5 (148 x 210 mm) needs 1748 x 2480, and A3 (297 x 420 mm) needs 3508 x 4961. Every A size has the same shape, a ratio of 1 to 1.414, which means an A4 design scales to A3 or A5 without cropping.
US Letter is 216 x 279 mm, or 8.5 x 11 inches, which needs 2550 x 3300 pixels at 300 PPI. Letter is wider and shorter than A4, with a ratio of about 1 to 1.294, so a file made for one leaves a margin or loses an edge on the other. Make the file for the paper it will actually print on. Half-letter and the other common flyer formats are listed with their pixel counts on the standard flyer dimensions page.
How to check if a photo is big enough to print
- Find the pixel size. In Photoshop, open the Image Size dialog (Image, then Image Size) and look at Dimensions. In Preview on a Mac, choose Tools, then Adjust Size, and pick pixels in the menu next to Width and Height.
- Divide each side by 300. That gives the largest print at full quality. Divide by 150 for the largest poster.
- Compare the shape with the paper. A photo shaped 4:3 printed on 4 x 6 paper (3:2) loses a strip across the top and bottom, so crop it yourself and choose what goes.
- Set the print size without resampling. In Photoshop's Image Size dialog, turn off Resample and type 300 in Resolution to see the print size in inches. In Preview's Adjust Size, turn off "Resample image" first, then type the new size. Both keep every pixel.
These are the largest prints some common files can make:
| File | Pixels | At 300 PPI | At 200 PPI | At 150 PPI |
|---|---|---|---|---|
| Instagram portrait post | 1080 x 1350 | 3.6 x 4.5 in | 5.4 x 6.8 in | 7.2 x 9 in |
| HD video frame | 1920 x 1080 | 6.4 x 3.6 in | 9.6 x 5.4 in | 12.8 x 7.2 in |
| 4K video frame | 3840 x 2160 | 12.8 x 7.2 in | 19.2 x 10.8 in | 25.6 x 14.4 in |
| 12-megapixel photo | 4032 x 3024 | 13.4 x 10.1 in | 20.2 x 15.1 in | 26.9 x 20.2 in |
A photo saved from social media is usually far smaller than the one on your phone, so print from the original. Instagram's own size rules explain why posts top out at 1080 pixels wide.
Why raising the DPI number doesn't add detail
The only way to get more pixels is to create them, which is called resampling or upscaling. With resampling turned on, typing 300 into the resolution box makes the software add new pixels between the old ones. The file gets bigger, but no new detail appears, because the extra pixels are blends of their neighbors. 4OVER4 puts it plainly: a small photo pushed from 72 to 300 in an editor only stretches what was already there.
AI upscalers make a better guess at missing detail, which helps when a file is a little short of the size you need. They can also invent texture that wasn't in the scene. Free and paid upscalers are compared, with steps, in how to add pixels to a photo.
Common print resolution mistakes
| Problem | Likely cause | Fix |
|---|---|---|
| Edges look fuzzy or show little squares | Under about 150 PPI at the printed size | Print smaller, or use the original file |
| The shop says the file is low resolution, but it says 300 DPI | The label was changed, not the pixel count | Check the pixel dimensions and use a bigger file |
| Heads or edges are cut off | The photo's shape differs from the paper's | Crop to the paper's shape before you upload |
| A social media photo prints tiny or blurry | The downloaded copy is only about 1080 pixels wide | Find the original on the phone or camera |
| Small text on a flyer looks fuzzy | Text inside a photo printed below 300 PPI | Keep flyers at 300 PPI and make type large enough to read |
| A thin white line along one edge | The design stops exactly at the trim line | Ask the shop about bleed; 4OVER4's guide uses 0.125 inch on each edge |
Printing a flyer made in Flyer Maker
Flyer Maker in Toybox AI makes each flyer as a PNG at a fixed pixel size, so you can work out the print size before you order. For printing, choose 2K or 4K. At 4K the three sizes come out like this:
| Flyer Maker size | Pixels at 4K | Prints at 300 PPI | Also covers |
|---|---|---|---|
| Tall (3:4) | 2480 x 3312 | 8.3 x 11 in | US Letter at about 290 PPI with a slight trim; an 18 x 24 poster at about 138 PPI, just under the 150 PPI poster guideline |
| Portrait (4:5) | 2560 x 3200 | 8.5 x 10.7 in | An 8 x 10 print at exactly 320 PPI |
| Wide (5:4) | 3200 x 2560 | 10.7 x 8.5 in | A 10 x 8 print at 320 PPI |
On A4, the 4K Tall file fills the page width at 300 PPI and leaves about 1/3 inch of margin at the top and bottom. At 2K, Tall is 1536 x 2048 pixels, enough for a 5 x 7 card at about 290 PPI after trimming about 1/4 inch off the width. At the default 1K quality, Tall is 1024 x 1360 pixels, only 3.4 x 4.5 inches at 300 PPI, so change Quality before you make a flyer meant for paper.
- Start in Flyer Maker by typing the full wording into "Describe your flyer": the name, day, date, time, street address, price and the one thing you want readers to do.
- Choose Tall under "Size" for letter or A4 paper.
- Set Quality to 4K under "More options". Flyer Maker currently costs 80 credits per flyer, 90 for 2K and 100 for 4K.
- Create the flyer, then proofread every date, time, address, price and phone number. Typing a fix into "Want to change something?" on a 4K flyer currently costs 90 credits, or you can edit your description and make a fresh flyer.
- Download the PNG and send it to the printer. The file is an RGB PNG with no bleed, crop marks or DPI setting, so ask the shop how they want files and whether they need extra margin at the edges.