Perimeter ÷ sleeper length, times the number of courses. A 2.4m × 1.2m bed has a 7.2m perimeter = 3 × 2.4m sleepers per course, so a two-course bed needs 6 sleepers.
| Project | Sleepers needed | Notes |
|---|---|---|
| 2.4m × 1.2m bed, 2 courses | 6 × 2.4m sleepers | The classic bed |
| 3m × 1.2m bed, 2 courses | 8 × 2.4m sleepers | With a centre join |
| 2.4m × 1.2m bed, 3 courses | 9 × 2.4m sleepers | Waist-high |
| 10m garden edge, 1 course | 5 × 2.4m sleepers | Straight run |
Total edging length ÷ 2.4m, rounded up. A 10m edge needs 5 sleepers (4.17 → 5). Curves need more cuts: add 10%.
New (often oak or treated pine): clean, consistent sizes, safe for seating. Reclaimed creosote-treated: cheaper, characterful, but not recommended where people or pets touch them regularly — and prohibited in some settings.
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