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Sleeper Calculator — Railway Sleepers for Gardens
Work out how many railway sleepers you need for raised beds or retaining walls.
Outside length of the longer side. Sides longer than one sleeper are butt-jointed from more than one.
Outside width of the shorter side. Short ends are cut from a single sleeper where more than one will fit.
Number of stacked rows. One course (200mm) suits edging; two (400mm) is typical for veg beds; three or more for retaining walls.
Length of each sleeper in metres (default 2.4m for new softwood)
Number of coach screws or fixings per sleeper (default 2)
How We Calculate This
Each course needs two pieces the length of the bed and two the width, so the cut list is those four pieces repeated for every course. Any side longer than one sleeper is split into whole sleepers plus a remainder. We then pack that list into as few sleepers as possible, largest piece first, fitting each one into a sleeper that still has room before opening a new sleeper.
This is why short ends do not each cost a whole sleeper. A 2.4m by 0.5m bed two courses high needs four 0.5m ends totalling 2.0m, and all four come out of one 2.4m sleeper, so the answer is 5 rather than 8. The cutting plan shows which sleepers get cut and where, so you can check it against the timber in front of you. Set the Sleeper Length under Advanced Options if you are buying a size other than 2.4m.
Frequently Asked Questions
New green-treated softwood: typically 2.4m x 200mm x 100mm. Reclaimed oak (hardwood): 2.6m x 250mm x 150mm — the size most UK reclaim merchants now stock (older mainline oak was 125mm thick). Set the actual length you are buying under Advanced Options if it differs.
Use coach screws (200mm+), threaded rod, or metal brackets. Pre-drill to prevent splitting.
Old creosote-treated sleepers should not be used for food growing. Use new untreated or pressure-treated sleepers.
New untreated or green-treated softwood sleepers are safe. Old railway sleepers may contain creosote (a carcinogen) and should not be used for vegetable beds.
Use long timber screws (200mm+), coach bolts, or rebar driven through drilled holes into the ground. Stack them in a brickwork pattern for extra strength.
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Last updated: February 2026
All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.