Online Tool Store
Rule of Thirds Overlay
Overlay a rule-of-thirds grid and power points on any photo to check composition, then download the result. Runs entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Choose an image to preview the overlay.
How it works
- Choose an image from your device.
- The image is drawn to a canvas with two evenly spaced vertical and horizontal lines overlaid.
- Toggle power points to also mark the four line intersections — the strongest spots for a subject.
FAQ
What is the rule of thirds?
A composition guideline that divides an image into a 3×3 grid — placing key subjects along the lines or at their intersections ("power points") tends to produce more balanced, engaging photos than dead-center placement.
Does this modify my original image?
No — it draws the overlay onto a copy displayed in the browser; nothing about the original file is changed unless you choose to download the overlaid version.
Can I check composition without downloading anything?
Yes — the grid and power points render as a live preview the moment you choose a file, no download required to just look.
Is my photo uploaded anywhere?
No — the image is loaded and drawn locally with the Canvas API and never leaves your device.
What image formats does this accept?
Any image format your browser can decode — JPEG, PNG, WebP, and more — since the file picker accepts general image files, not just one format.
How we compare
| Feature | Online Tool Store | Camera app grid overlay | Photo editor guide layer |
|---|---|---|---|
| Works on photos already taken | ✓ | ✗ (shoot-time only) | ✓ |
| No editing software needed | ✓ | ✓ | ✗ |
| Downloadable overlay image | ✓ | ✗ | ✓ |
If you're reviewing a photo after the fact and want to check its composition without opening a full editor, this shows the grid instantly.