Frame Size Calculator
Enter your print size, the mat border you want and the width of the frame moulding. The calculator gives the mat window, the frame's inside and outside size and the nearest ready-made frame.
- Mat window cut
- Inside and outside size
- Ready-made match
Enter 0 for the mat if you want the print to fill the frame.
A frame is sized from the inside out. The mat window overlaps the print slightly so its edges stay hidden. The mat border then sets the size of the glass and the frame opening. Finally, the moulding adds to the outside size on the wall.
Frame and mat chart
Common pairings. Search for a print size.
| Mat opening | Frame size | |
|---|---|---|
| 10 × 15 cm (4 × 6 in) | 9 × 14 cm | 20 × 25 cm |
| 13 × 18 cm (5 × 7 in) | 12 × 17 cm | 20 × 25 cm |
| 20 × 25 cm (8 × 10 in) | 19 × 24 cm | 28 × 35.5 cm |
| A4 | 20 × 28.7 cm | 30 × 40 cm |
| 20 × 30 cm | 19 × 29 cm | 30 × 40 cm |
| A3 | 28.7 × 41 cm | 40 × 50 cm |
| 30 × 40 cm | 29 × 39 cm | 40 × 50 cm |
| 40 × 50 cm | 39 × 49 cm | 50 × 70 cm |
Ready-made frames often come with a mat cut for a smaller print. Check the opening size, not just the frame size.
Mat border and frame size
20 × 30 cm print, 2 cm moulding. Slide the mat border.
A wider mat makes small work feel more important on the wall and gives it room to breathe.
How to size a frame
Inside out. Step through it.
Measure the print
Width and height.
For a classic look, make the bottom mat border about 1 cm wider than the top and sides. It stops the picture looking as if it is sliding down.
Narrow, medium or wide mat
Choosing a border. Compare them.
Modern and minimal. Suits large prints.
The usual choice for most pictures.
Gallery style. Draws the eye to small work.
A mat also keeps the glass off the print, which protects it from damp and sticking.
Before ordering a frame
Avoid mistakes. Tick each item.
Tick each item as you go.
Use acid-free mat board for anything valuable. Standard board can yellow and stain the print over time.
What you get
Every frame size. Each tile explains one result.
Inside opening.
Cut size.
On the wall.
Nearest stock frame.
Length to buy.
Moulding length includes the extra needed for mitred corners plus a little for cutting.
Frequently Asked Questions
No question matches that search.
What size frame for an A4 print?
30 × 40 cm with a mat, or an A4 frame without one.
What size frame for an 8 × 10 print?
11 × 14 in with a mat.
How big should the mat window be?
About 5 mm smaller than the print on each side.
How wide should a mat be?
5 to 8 cm suits most prints.
Is frame size the inside or outside?
Frame size is the inside opening, which is also the glass size.
What size frame for a 5 × 7 photo?
8 × 10 in (20 × 25 cm) with a mat.
Should the bottom mat border be wider?
Often yes, by about 1 cm, for visual balance.
The right frame every time
Start with the print, cut the window, add the mat and the moulding. You will know the frame size to buy and how big it will look on the wall.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.