Color by Number Generator
Upload a photo and get a printable colour-by-number sheet with a matching key. Everything runs in your browser — your photo is never uploaded.
Upload a photo to build a sheet.
How to use it
- Upload a photo. Bold, simple images with clear areas of colour work far better than busy scenes.
- Set how many colours. Three or four suits young children and a small crayon box; eight or ten gives a more photographic result.
- Set the detail. Fewer squares means bigger, easier cells; more squares means a recognisable picture but tiny numbers.
- Switch to “Coloured answer” to see what the finished sheet should look like, and print that copy as a key if you want one.
- Print, or download the PNG. The key at the bottom tells the child which number is which colour.
How many colours to choose
This is the setting that decides whether the sheet is a pleasure or a chore, and the right answer depends on the subject as much as the age.
| Colours | Result | Use for |
|---|---|---|
| 3–4 | Poster-flat, very easy | Ages 3–5, and a small crayon box |
| 5–7 | Recognisable, still simple | Ages 6–9. The best default |
| 8–10 | Close to the photograph | Older children and adults, and any picture with gradients |
Faces are the exception. Skin is a narrow band of close mid-tones, so at six colours a face posterises into a flat mask. Either use the top of the range, or pick a different subject — landscapes, buildings, animals and single objects all survive a small palette far better than people do.
What posterising does to your photo
The tool reduces the picture to the number of colours you asked for, then draws each grid cell as the closest one. The result is flat fields with hard edges — closer to a screen print than a photograph. That is the point: a colour-by-number needs regions a child can fill, not a gradient. Two knobs control it. Fewer colours merges neighbouring shades into one region, and fewer squares makes each region physically bigger. Both make the sheet easier; both make it less like the photo. Move them together rather than one at a time.
Which photos make good colour-by-numbers
Note that this is a different answer from the coloring page converter, which wants edges. This wants areas.
- Very good: a sunset, a barn or beach hut, a single flower, a pet against a plain wall, a fruit bowl — broad blocks of flat colour with strong separation between them.
- Mixed: skies and skin, which fragment into visible bands unless you raise the colour count.
- Poor: anything busy or low-contrast, where every cell ends up a slightly different number and the sheet becomes noise.
How to actually colour one
- Work one number at a time across the whole page, rather than one area at a time. Fewer tool changes, and far fewer mistakes.
- Go light to dark. Covering a light colour with a dark one is easy; the reverse is not.
- Pull the colours out first using the key, so a child is not hunting through the box mid-flow.
- Coloured pencils are the best match for a printed sheet. Crayons cannot reliably hit a small cell, and markers cover the printed number as you go — so with markers, colour the smallest regions last.
Colour by number as maths practice
The classroom version of this activity replaces the numbers with something to work out: regions labelled 7+5 to be coloured in colour 12, or with times tables, fractions or sight words. This tool prints plain numbers, but the same sheet works for that if you write the sums in yourself before photocopying — pick a low colour count so there are few enough distinct numbers to build questions around. For which medium suits which age, our comparison of crayons, coloured pencils and markers covers the practical differences.
Frequently asked questions
Is my photo uploaded?
No. The image is reduced and analysed in your browser with a canvas; nothing leaves your device.
How does it choose the colours?
It clusters the pixels into the number of colours you asked for, picking the most representative shades in the photo, then sorts them light to dark for the key.
What detail level should I use?
For children under about 7, keep it around 16–24 squares wide so each cell is big enough to colour and the number is readable. Older children and adults can go to 50+.
The colour names look approximate.
They are — the key gives both a swatch and a plain-English name, and the swatch is the accurate one. Match the swatch rather than the word if your crayon box differs.
Why squares rather than shaped regions?
A grid guarantees every cell is big enough to hold a number and to colour inside. Traced regions look prettier but frequently come out too small or too thin to use.
Can I see the finished version?
Yes. Switch to “Coloured answer” and the same grid is filled with the palette colours instead of numbers. Print that as a key, or use it to check the sheet is worth printing before you commit paper to it.
How many colours should I use?
Three or four for ages 3–5, five to seven for most children, eight to ten for adults or any photo with gradients. Faces need the top of the range or they posterise into a flat mask.
Why do I get fewer colours than I asked for?
Because two of them came out nearly identical, and two swatches a child cannot tell apart with two different numbers is worse than one. Near-duplicates are merged.
Can I use this in a classroom?
Yes, print as many as you need. Reselling the generated sheets, or publishing them in a book for sale, is not permitted.