Stepping stone calculator
Enter the path length, your stone size and how big a gap you want between stones — get the stone count and the gravel needed to bed them properly.
Stepping stones needed
How many stepping stones do I need?
A comfortable walking rhythm puts stepping stones 24–30 inches on center — roughly your stride. That means an edge gap of 2–6 inches between typical 16–24 inch stones. The count along a path:
Worked example: a 20 ft path with 18 in stones and 6 in gaps: 240 in ÷ 24 in = 10 stones. Tighten the gap to 4 in and you need 11 — spacing changes material fast on long runs.
Set them so they don't wobble
A wobble is the one thing people remember about a path. Dig each stone in 1–2 inches below grade on a bed of compacted sand or screenings, tap it level with a rubber mallet, and check with a string line. The bedding gravel figure the calculator gives is a 2-inch bed under every stone — a 20-stone path with 18 in stones needs about 5.9 ft³ of screenings.
| Stone ⌀ | Gap | Stones per 20 ft |
|---|---|---|
| 12 in | 4 in | 15 |
| 18 in | 6 in | 10 |
| 24 in | 6 in | 8 |
Fill between the stones
Pea gravel, decomposed granite or mulch make good joint fill — pea gravel is the classic and sweeps clean. Keep stones ½ in proud of the fill so shoes don't clip them, and install edging along the path sides if you use loose fill, or it migrates into the lawn within a season.
What do stepping stones cost?
Concrete pavers run $5–$15 each, natural flagstone $10–$25, and cast-your-own molds cost one bag of concrete per stone. A 20 ft path with ten 18 in stones lands around $80–$200 in stone, plus $30–$50 of screenings and joint fill.