Limestone Calculator

Volume = area × depth, then multiply by the density for tonnage. A 40 × 10 ft driveway (400 sq ft / 37 m²) of #57 limestone at 3 in (75 mm) is about 3.7 yd³ (2.8 m³); at roughly 1.35–1.5 US tons per cubic yard (1.55 t/m³) that is about 5 US tons (4.5 t) — order around 5.5 US tons with a 10% compaction allowance. The calculator handles the grade, units and allowance for you.

Two layers: a compactable base of crusher run (#411) — crushed stone with fines that lock together when compacted — topped with a 2–3 in (50–75 mm) wearing course of #57 (¾ in clean stone) for drainage and a clean look. Size and price each layer separately at its own depth; the calculator lets you switch grade and depth for each.

About 1.35–1.5 US tons per cubic yard of crushed limestone (roughly 1.5–1.65 tonnes per m³), because it weighs around 95–100 lb per cubic foot. So 10 yd³ is about 14 US tons. Crusher run packs a little denser than clean #57; your quarry can give the exact figure for their stone.

#57 is ¾ in “clean” stone with no fines — it drains freely and won’t compact hard, so it’s used as a surface, in drains and around pipe. Crusher run (#411) mixes stone with stone dust, so it compacts to a solid, load-bearing base. Use crusher run underneath and #57 on top. Pick the matching grade so the density and depth are right.

For a driveway, about 4 in (100 mm) of compacted crusher run base plus 2–3 in (50–75 mm) of #57 on top. Paths and drainage need less; heavy-traffic or soft-ground jobs need more base, ideally laid and compacted in two lifts over a geotextile. The calculator defaults to a sensible depth per grade — adjust it to your job.