String Art Generator
100% private — runs on your device, never uploaded. Works offline once loaded.
Turn a portrait into thread art you can make by hand: one continuous thread wound between nails set in a circle. Position the photo, choose a 240 or 200 nail board and how many lines of thread to use, then compare three styles generated side by side. Pick your favourite and you get a simulated preview, the thread length you will need, a printable PDF checklist and a winding mode that walks you through every nail — labelled in four clockwise quarters, A1 to D60, so it matches your physical board. The pattern is computed with a deterministic line-optimisation algorithm on your own device; the photo is never uploaded.
How the pattern is calculated
String art is made from one continuous thread wound back and forth between nails around a circle. Every straight line between two nails adds a little darkness to the board, and thousands of overlapping lines build up the picture. The generator works that out the same way the best-known string art apps do: with a deterministic, greedy line-optimisation algorithm — not AI image generation.
Your photo is cropped to the circle, converted to greyscale and its tones are levelled so the whole range from white to black is used. Starting at A1, the algorithm tries every nail the thread could go to next, measures how much dark picture is still left along each straight line, and takes the best one. It subtracts that thread from the picture and repeats — 3,500 times for a typical portrait. Because nothing is random, the same photo and settings always produce exactly the same sequence.
Three styles from one photo
Every photo is solved three ways at once so you can compare them side by side before committing hours to winding:
- Bold — keeps returning to the darkest areas, so shadows, hair and eyes are strong and the background stays light. Good for dramatic, high-contrast portraits.
- Balanced — spreads thread in proportion to the photo's tones. The safest choice for most faces.
- Fine detail — sharpens the photo first and lets thread spread more evenly, which keeps texture and mid-tones at the cost of a greyer background.
Choosing a board and line count
A 240-nail board gives finer detail and is the better choice for portraits; 3,000–4,000 lines is the usual range. A 200-nail board is quicker to build and suits 2,500–3,500 lines. More lines make the piece darker and more detailed but use more thread and take longer, so the line count is adjustable from 1,000 to 6,000 — the thread estimate updates with it. Enter your board's diameter to see how much thread to buy, and add around 10% for wrapping each nail and tying off.
For the clearest result, use a sharp, well-lit close-up where the face fills most of the circle, on a plain light background. Busy or dark backgrounds use up thread that would otherwise go into the face.
Following the instructions on a real board
Label your nails in four equal quarters, clockwise from 9 o'clock: A from 9 to 12, B from 12 to 3, C from 3 to 6 and D from 6 to 9, each numbered from 1. Tie the thread to the starting nail, then take it straight across to each nail in the list in turn, wrapping once around each. The printable PDF has a labelled board map and a tick-box checklist of 250 steps per page; winding mode shows one step at a time with the line highlighted on the board, can read the next nail aloud, and remembers where you stopped on this device.
Frequently asked questions
Is my photo uploaded anywhere?
No. Everything — cropping, solving the pattern, building the PDF — runs in your browser. The photo never leaves your device, and the tool keeps working offline once the page has loaded.
Does this use AI to generate the image?
No. It uses a deterministic greedy line-optimisation algorithm, the standard method for string art. The preview is a simulation of exactly the lines in your instructions, so what you see is what you will wind.
How are the nails labelled?
In four clockwise quarters starting at 9 o'clock: A (9 to 12), B (12 to 3), C (3 to 6) and D (6 to 9). On a 240-nail board each quarter is numbered 1 to 60, so nails run A1–A60, B1–B60, C1–C60 and D1–D60. A 200-nail board has 50 per quarter, A1 to D50.
How many lines should I use?
For a 240-nail board, 3,000 to 4,000 lines; for 200 nails, 2,500 to 3,500. Start with the default, look at the preview, and use the "Show lines" slider to see how the piece looks with fewer threads.
How much thread do I need?
Enter your board diameter and the tool adds up the length of every line. Buy about 10% more than the estimate to allow for wrapping around nails and knots.
Which photos work best?
Sharp, well-lit close-up portraits on a plain, light background. Zoom in so the face fills the circle. Very dark photos or busy backgrounds spend thread on areas that are not the subject.
Can I make white thread on a black board?
Yes. Choose "White on black" and the pattern is recalculated for light thread on a dark board — it is a different sequence, not just an inverted preview.
Will I lose my place if I close the page?
Winding mode saves your current step on this device. Upload the same photo with the same crop and settings and it picks up where you left off. The printable PDF checklist is the safest backup for a long build.
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