The Gravel Calculator
Estimate exactly how much gravel you need — volume, weight, bags and cost — for driveways, walkways, patios and drainage projects. Every result comes with the math shown step by step, so you can check it before you order.
Calculate your gravel
Fill in the four steps on the left. Results update live on the right — including the safety overage, bag counts and a cost estimate. Switch units any time; your dimensions convert automatically.
Project details
What are you building?
pre-fills depth & materialArea & depth
measure the space to coverGravel type
sets the density used for weightOverage & pricing
optional but recommendedHow the math works
No black box. These are the exact formulas the calculator uses — filled in with your current numbers, live. Change any input above and watch them update.
Choosing the right gravel
Density drives the weight calculation, and shape drives performance. Angular stone locks together and compacts; rounded stone drains well and feels softer underfoot but shifts. The material you picked in the calculator is highlighted.
| Type | Typical size | Density | Best for | Character |
|---|---|---|---|---|
| Crusher Run / Road Base | ¾″ minus (stone + fines) | 1.60 t/yd³ · 1,900 kg/m³ | Driveway base, parking areas | Compacts rock-hard; best structural base |
| Crushed Stone (#57) | ¾″ angular | 1.50 t/yd³ · 1,780 kg/m³ | Driveways, drainage, concrete base | Locks together, drains well, versatile |
| Pea Gravel | ⅜″ rounded | 1.40 t/yd³ · 1,660 kg/m³ | Walkways, playgrounds, dog runs | Smooth & comfortable; shifts — needs edging |
| River Rock | 1–3″ rounded | 1.35 t/yd³ · 1,600 kg/m³ | Decorative beds, dry creek beds | Attractive, stays put; hard to walk on |
| Crushed Limestone | ¾″ angular | 1.50 t/yd³ · 1,780 kg/m³ | Driveways, farm lanes, base | Compacts well; can lighten soil pH nearby |
| Decomposed Granite | ⅜″ minus | 1.30 t/yd³ · 1,540 kg/m³ | Paths, patios, xeriscaping | Firm natural surface; rustic look |
| Marble Chips | ½″ angular | 1.50 t/yd³ · 1,780 kg/m³ | Decorative beds, borders | Bright white sparkle; pricier, shows dirt |
| Lava Rock | ¾–1½″ porous | 0.65 t/yd³ · 780 kg/m³ | Mulch alternative, fire pits | Very light; half the weight per yard |
Recommended depths
Depth is the number people most often get wrong. Too thin and the soil shows through and ruts form; too thick and rounded stone becomes unstable. These are field-tested ranges.
| Application | Recommended depth | Notes |
|---|---|---|
| Driveway — per layer | 4–6 in · 10–15 cm | Compact each layer before adding the next; never dump the full depth at once. |
| Driveway — total build-up | 8–12 in · 20–30 cm | Three layers: coarse base → #57 mid → fine top (see diagram below). |
| Walkway / garden path | 2–3 in · 5–8 cm | Over landscape fabric; use edging for rounded stone like pea gravel. |
| Patio / paver base | 4–6 in · 10–15 cm | Compacted crushed stone, plus 1″ bedding sand under pavers. |
| French drain / drainage | 6–8 in · 15–20 cm | Clean (washed) ¾″ stone only — fines clog drainage. Wrap in geotextile. |
| Decorative ground cover | 2–3 in · 5–8 cm | Enough to fully hide the fabric/soil below; refresh top-up every few years. |
| Playground (pea gravel) | 6–12 in · 15–30 cm | Deeper = better fall cushioning; check local safety guidelines. |
Anatomy of a long-lasting gravel driveway
A driveway that stays smooth for a decade is built in layers, not dumped in one go. Each layer is spread, watered lightly and compacted before the next goes down. Landscape fabric between the soil and the base stops the stone sinking into mud — the #1 cause of ruts.
Run the calculator once per layer with its own depth, or run it once with the total depth if you’re using a single material like crusher run for the whole build-up.
Pro tips before you order
The difference between a gravel project that lasts and one that fails in a year is almost always preparation, not the stone itself.
Excavate & level first
Remove topsoil and organic matter. A firm, level subgrade is the foundation of everything above it.
Lay landscape fabric
Geotextile fabric stops weeds and prevents stone mixing into soil — the main cause of disappearing gravel.
Compact in thin lifts
Compact every 2–3″ with a plate compactor. Lightly wetting the stone first dramatically improves compaction.
Install solid edging
Steel, stone or timber borders keep rounded gravels from migrating into lawns and beds.
Slope for drainage
Crown driveways or slope ≈ 2% (¼″ per foot) so water sheds off instead of pooling and pumping the base.
Order ~10% extra
Spillage, uneven ground and settling always eat some material. Running short mid-job costs more than the extra.
Time the delivery
Have the site prepped before the truck arrives. Dump it as close to the final spot as access allows.
Maintain annually
Rake level each spring and top up thin spots. A little upkeep doubles the life of the surface.