Mural Grid Calculator
Work out exactly how to scale a small reference up to a wall using the grid method. Enter your reference and wall measurements and get the scale factor, the size of each square on the wall, and printable transfer instructions.
- Free
- No signup
- No watermark
- Browser-based
Measurements
Reference image
Wall
Result
Transfer instructions
Draw a 12×15 grid on both, then copy one square at a time. Each wall square is 8 in (in).
How to use the mural grid calculator
- 1
Enter your reference image width and height.
- 2
Enter the wall width and height.
- 3
Choose the number of columns — rows stay square.
- 4
Read the scale factor and download the instructions.
Features
- Scale factor between reference and wall
- Exact square size on the wall
- Square cells kept proportional automatically
- Aspect-ratio mismatch warning
- Downloadable transfer instructions PDF
Great for
- Painting a wall mural from a sketch
- Enlarging a design to a large surface
- Planning a grid before transferring
- Teaching scale and proportion
Frequently asked questions
How do I enlarge a drawing using the grid method?+
Draw a grid over your reference, then draw a larger grid with the same number of squares on the wall. Copy the contents of each small square into the matching large square.
How many squares should I use for a mural?+
More squares make transfer more accurate but take longer. 10–16 columns is a good starting point for most murals; complex designs benefit from more.
What if my reference and wall are different shapes?+
The calculator warns you when the proportions don't match. You can either crop the reference to the wall's shape or leave a margin so the squares still line up.