DIY & DECORATING
Plan even spacing with our wall panelling calculator
Plan one row of equal rectangular openings with vertical strips and a top and bottom rail. Use the numbers as a starting point, then check your real wall before buying or cutting.
Practical ideas, clear measurements and a little help getting started.
- Equal clear panel openings
- A practical strip cutting list
- No sign-up or contact details
Work out a simple strip layout
Enter centimetres for the overall width and panelled height, and millimetres for the visible strip width. Height includes the top and bottom rails. The wall itself forms the inside of each opening.
What the result includes
- One horizontal rail across the top and one across the bottom.
- A vertical strip at both outside edges and between each opening.
- Vertical pieces fitted between the two rails.
- Equal clear spaces inside the frames and the total strip length, with an optional planning allowance.
If you are measuring by hand
Convert the strip width to centimetres first: a 75 mm strip is 7.5 cm wide. Multiply that width by the number of openings plus one, then subtract the result from the wall width. Divide what is left by the number of openings to find each clear opening.
For a 300 cm wall with four openings and 75 mm strips, that is (300 − 5 × 7.5) ÷ 4 = 65.625 cm per opening. At a panelled height of 120 cm, the vertical strips fit between the rails and are 120 − 2 × 7.5 = 105 cm long. Two 300 cm rails and five 105 cm verticals total 11.25 metres before extra material.
See the four-opening layout
This uses the same 300 cm width, 120 cm panelled height and 75 mm strips as the worked calculation above. The numbered spaces are the clear openings, rather than the outside edges of the strips.
300 cm overall width
- Strips: 7.5 cm wide
- Overall height: 120 cm
- Each clear opening: 65.625 × 105 cm
What happens if you change the number of openings?
Keep the same wall dimensions and strip width, and compare these three layouts. Every vertical piece is 105 cm long and both horizontal rails are 300 cm long. More openings make the spaces narrower and add another vertical strip each time.
| Openings | Clear width | Vertical strips | Total length |
|---|---|---|---|
| 3 | 90 cm | 4 | 10.20 m |
| 4 | 65.625 cm | 5 | 11.25 m |
| 5 | 51 cm | 6 | 12.30 m |
The totals exclude spare material. For the four-opening layout, a 10% planning allowance gives 12.375 m, shown as 12.38 m by the calculator. That allowance does not guarantee the cuts will fit into the stock lengths you buy. Plan the individual rails and vertical pieces, joints and saw cuts separately.
Try three, four and five openings in the calculator, then mark out your preferred layout on the wall. There is no single best spacing: the room, furniture and obstacles may make one arrangement work better.
What you still need to check
This is for a straight wall with one row of rectangular openings. It does not calculate backing sheets, decorative mitre-cut frames, door or socket cut-outs, stair angles or several rows of panels. It also does not pack cuts into shop stock lengths. Plan actual stock lengths, joints, saw kerf and offcuts separately.
Try the layout on the wall
Use the clear opening width to mark out the first few spaces with a pencil or suitable removable tape. Include the strip face width every time: measuring only the gaps will make the pattern drift. Look at the finished rhythm from the doorway and with furniture in place.
If a socket or radiator breaks the grid, alter the number of openings or make a separate layout for that part of the wall. Measure at more than one point, because skirting, corners and ceilings are not always level or square. Keep actual measurements with your cutting list.
From total length to an order
A total of ten metres does not mean any ten metres of strips will produce the right pieces. Long rails may need a stock length long enough for the wall; shorter offcuts might suit the vertical pieces. Draw the cuts on each available stock length and leave room for the cut itself.
The optional allowance helps you think about spare material, but does not guarantee a successful stock-length plan. Choose the material, thickness, finish and fixing method before ordering. Read the panelling guide for the other items the job needs.
A few questions before you start
Does the calculator include the outside strips?
Yes. For four clear openings, it includes five vertical strips: one at each edge and three between openings.
What height should I enter?
The full panelled height, including both horizontal rails. The vertical pieces are that height minus the widths of the top and bottom rails.
Can I use it for decorative moulding frames?
No. Mitre-cut frames need their own frame dimensions, gaps and cutting allowances. This calculator is for plain strips joined between continuous top and bottom rails.
Still choosing the look?
See how shaker-style strips, moulding frames and sheet panels differ before deciding on a layout.
Reviewed 3 October 2026. These guides provide general project information. Follow the instructions for the products you choose and ask a suitable tradesperson when the work needs specialist skills.