Gravel Calculator
Free gravel calculator that turns area and depth into tonnes, volume, and cost for a driveway, path, or patio base.
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What is Gravel Calculator?
The Gravel Calculator converts the dimensions and finished depth of a driveway, path or patio base into the volume of aggregate you need, applies a compaction and waste allowance, and converts that into tonnes using typical loose densities for seven common materials. It totals the cost at your price per tonne and includes a coverage chart at 5, 7.5, 10 and 15 centimeter depths, so ordering the right load is a thirty-second job instead of a guess.
Key Benefits
- Tonnage for seven aggregates, from pea gravel to MOT Type 1
- Compaction allowance built in so the finished surface stays on target
- Instant cost totals at your own price per tonne
- Coverage chart compares decorative and structural depths in one pass
- Copyable order summary with material, volume, tonnage and cost
Common Use Cases
- •Ordering crushed stone for a new driveway or parking area
- •Estimating a decorative slate or pea gravel border
- •Sizing an MOT Type 1 sub-base under a patio or shed base
- •Comparing quotes from suppliers priced per tonne
- •Planning sand or grit for a horse arena or play area
How to Calculate Gravel Tonnage
- Measure the area: Enter the length and width in meters. For a curved driveway, split it into rectangles and add the areas, or measure the longest and widest points to stay on the safe side.
- Pick the material and depth: Choose the aggregate you are buying and set the finished depth: 5 centimeters suits decorative cover, 10 to 15 centimeters suits driveways, and sub-base layers run deeper still.
- Add a compaction allowance: Keep 10 percent for foot-traffic paths and driveways, or up to 20 percent over soft or freshly dug ground, so the surface settles onto your target depth rather than below it.
- Price the order: Enter the price per tonne quoted by your supplier for the total cost, then use the coverage chart to compare tonnage at other depths before you commit.
Key Features
- Tonnage from area and depth for seven common aggregates
- Material density presets from crushed stone to MOT Type 1
- Compaction and waste allowance from 0 to 50 percent
- Total cost from your price per tonne, updated as you type
- Coverage chart at 5, 7.5, 10 and 15 centimeter depths
Frequently Asked Questions
How many tonnes of gravel do I need per square meter?
Depth and material decide it: one square meter at 5 centimeters needs roughly 0.075 tonnes of pea gravel and about 0.08 tonnes of crushed stone, while a 10 centimeter driveway layer doubles that. Enter your area once and the coverage chart shows tonnage at 5, 7.5, 10 and 15 centimeters.
What compaction allowance should I add?
Ten percent is the usual allowance for driveways and paths once the aggregate is rolled or trafficked, and up to twenty percent over soft, freshly dug or clay ground. Decorative cover that is never compacted needs little or none. The calculator adds the allowance on top of the finished volume so the delivered pile settles onto your target depth.
How much area does a tonne of gravel cover?
A tonne of typical crushed stone at 1.6 tonnes per cubic meter covers about 12.5 square meters at 5 centimeters, 6 square meters at 10 centimeters and 4 square meters at 15 centimeters. Lighter materials such as slate chippings go further, and the coverage chart applies the same math to your exact area.
Which density should I choose?
Pick the material you are actually buying: the presets use typical loose stockpile densities from 1.4 tonnes per cubic meter for slate chippings up to 2.1 for MOT Type 1. If your supplier quotes a density on the spec sheet, choose the closest preset — a few percent difference between loads is normal.