Coping Stone Calculator
How many coping stones do you need? The usual sum divides the wall length by 600mm and adds 10%, which forgets the joints between the stones. Enter your runs of wall and get every stone laid out with its joints, the cut pieces cut from as few stones as possible, and the overhang checked.
Last reviewed: 30 September 2026
Wall and Coping
A one-brick wall is 215mm thick, a half-brick wall 102.5mm. Enter each run as the length of coping it needs. At a corner, one run goes to the outside face and the other stops against it.
How Many Coping Stones Do I Need?
Primethorpe's guide says divide the wall length by 600mm and add about 10% for cuts and breakages. It over-buys, because the stones go down with a 10mm joint between each, so every stone covers 610mm of wall, and the cut pieces can share stones. A 6m wall comes to 11 stones by the sum and needs 10. In the table below the sum is over in 7 of 7 walls.
The 10% is there for breakages as well as cuts, so a spare stone is still worth thinking about. This calculator shows the plan count and a spare separately, so you can decide.
How the Plan Works
- Joints. Primethorpe: "a 10 mm gap between each coping stone".
- Cut pieces. Whole stones along each run, then a cut piece. No piece under 150mm: the last two share the length instead (our rule).
- Offcuts reused. Cut pieces come out of whole stones longest first, with a 3mm cut, so one stone can make two short pieces (our working).
- Overhang. Primethorpe: about 20-30mm each side. The calculator checks it for your wall.
- Mortar bed. Primethorpe: about 20-30mm. The calculator works the bed out at 25mm.
What it does not do: pier caps, curved walls, or the mortar in the joints.
Coping Sizes, With Sources
Every coping in the dropdown has a Wickes product page. All are 600mm long.
| Coping | Product page |
|---|---|
| Marshalls Saxon, 600 x 136mm (buff) | Marshalls Saxon Textured Buff Coping Stone, 600 x 136 x 50mm |
| Marshalls smooth cast, 600 x 140mm (grey) | Marshalls Smooth Cast Grey Coping Stone, 140 x 600 x 50mm |
| Marshalls Saxon, 600 x 272mm (buff) | Marshalls Saxon Textured Buff Coping Stone, 600 x 272 x 50mm |
| Marshalls smooth cast, 600 x 280mm (grey) | Marshalls Smooth Cast Grey Coping Stone, 280 x 600 x 50mm |
The joint, overhang, bed and the usual sum are from Primethorpe's guide to installing coping stones. The shortest piece, the cut allowance and the packing are our own working.
Common Walls: Stones Needed
Generated from the calculator above, for 600 x 272mm coping on a 215mm wall.
| Runs | Stones | Whole | Cut Pieces | Length / 600 + 10% |
|---|---|---|---|---|
| 3.0m | 5 | 4 | 1 | 6 |
| 6.0m | 10 | 9 | 1 | 11 |
| 10.0m | 17 | 16 | 1 | 19 |
| 4.5m + 2.0m | 11 | 10 | 2 | 12 |
| 2.4m + 2.4m + 2.4m | 12 | 9 | 3 | 14 |
| 5.0m + 5.0m | 17 | 14 | 4 | 19 |
| 8.0m + 3.0m + 8.0m | 32 | 28 | 5 | 35 |
Frequently Asked Questions
How many coping stones do I need?
Primethorpe's guide says divide the wall length by 600mm and add about 10% for cuts and breakages. But the stones go down with a 10mm joint between each, so every stone covers 610mm, and a cut piece can often come out of another cut stone's offcut. A 6m wall comes to 11 stones by the sum, and the plan needs 10. In the table below the sum is over in 7 of 7 walls.
How wide should the coping be?
Wider than the wall, so rain drips clear of the face. Primethorpe suggests an overhang of about 20-30mm each side. A 272mm coping on a 215mm wall overhangs 28.5mm each side. A 136mm coping on a 102.5mm wall overhangs 16.8mm, a little under, and the calculator says so.
Where does the cut stone go?
Each run is laid with whole stones and a cut piece to finish. If that piece would be shorter than 150mm, the calculator shares the length between the last two stones instead, so there is no sliver (our rule). A 5m wall gets 570mm and 150mm pieces at the end. Put the cut pieces where they show least.
How much mortar do I need for the bed?
Primethorpe says lay a mortar bed about 20-30mm thick. At 25mm under a 272mm coping, the default 6.5m of wall takes about 44 litres, plus the joints. For bags of cement and sand, use the mortar calculator.
What about corners and piers?
Enter each run of wall as the length of coping it needs, so at a corner one run goes to the outside face and the other stops against it. Pier caps are separate and not counted.