Gravel Calculator
Gravel volume, weight in tons, and bag count from area, depth, and material.
Written by Golam Rabbani, Founder & Lead Engineer
How to use this gravel calculator
- Toggle between imperial (ft / in) and metric (m / cm).
- Enter the area length, area width, and the depth of the gravel layer.
- Pick the material — pea gravel, crushed stone, river rock, or dry sand.
- Choose the bag size you can buy locally (50 or 70 lb).
- Press Calculate to see volume, total weight, and bag count.
About this gravel calculator
The gravel calculator finds how much gravel, sand, or crushed stone you need by volume and weight. It multiplies length × width × depth to get a volume in cubic yards and cubic metres, then multiplies that volume by the bulk density of the chosen material to give a total weight in tons. The published bulk densities used (1500–1700 kg/m³) are typical compacted-loose figures for landscape and construction aggregates.
Worked example: a 20 ft × 8 ft driveway needs a 3-inch layer of 3/4-inch crushed stone. The volume is 20 × 8 × 0.25 = 40 ft³, which is 1.48 yd³ or 1.13 m³. At a bulk density of 1600 kg/m³ for crushed stone, that's 1810 kg ≈ 1.99 US tons. If you are buying 50 lb bags from a hardware store, 1.99 × 2000 ÷ 50 = 80 bags. Most yards will sell loose by the ton more cheaply, but bags are practical for small jobs.
Bulk density varies with moisture and compaction. Dry-loose pea gravel sits around 1700 kg/m³; the same gravel wet and packed can hit 2000 kg/m³. Add 5–10% to your purchase to account for compaction loss when you spread and tamp, and check your supplier's published density if precision matters for a load-rated job.
FAQ
- How many tons of gravel do I need per cubic yard?
- Around 1.3–1.5 US tons per cubic yard for typical landscape gravel and crushed stone. River rock is lighter (~1.2 t/yd³); dense crushed limestone is heavier (~1.4 t/yd³).
- How deep should a gravel driveway be?
- A typical driveway uses 4 inches of crushed stone over a compacted base. For a top dressing of decorative pea gravel, 2–3 inches is enough.
- Why does the same area need different weights for different materials?
- Each material has a different bulk density. River rock is rounded and packs loosely (~1500 kg/m³); crushed stone is angular and packs tightly (~1600 kg/m³); dry sand is fine and dense (~1600 kg/m³). The volume is the same but the weight differs.
- Should I order loose by the ton or bagged?
- Loose by the ton is much cheaper above ~½ yd³ if you have a place for it to be dumped. Bagged is convenient for small jobs and where access is tight, but at typically 4–8× the per-pound cost.
- How accurate is the weight number?
- Within ±10% for most jobs. The bulk densities used are typical-published values; field densities vary with moisture and compaction.
- Is this calculator free?
- Yes — completely free, no signup, runs in your browser.