Gravel Calculator

How this is calculated

Volume is length times width times depth, with the depth converted from inches to feet. Cubic feet become cubic yards by dividing by 27. Tons is that volume multiplied by a density. The default is 1.4 tons per cubic yard, which is a common figure for loose crushed gravel - but density is a genuine range rather than a constant, so it is an input. Loose material generally runs about 1.35 to 1.5 tons per cubic yard, some crushed stone reaches 1.7, and compacted gravel is heavier again at around 1.55. Ask your supplier for the figure for the material you are actually buying; a 20 percent difference in density is a 20 percent difference in your bill. ⚠️ SUPPLIERS ARE SPLIT ON WHICH UNIT THEY SELL BY, and the numbers are not close - about 5.9 cubic yards of the default job is about 8.3 tons. Ordering '6' when they price by the ton, or '8' when they price by volume, is a substantial and expensive error in either direction. Check the unit before you quote a number. Depth is the input people most often understate. Four inches is a common figure for a gravel driveway surface, and a driveway built properly is usually several layers with a coarser base beneath the top course - so the total excavation is considerably deeper than the surface layer you are pricing. A path or a decorative bed is fine much shallower, often two inches. Gravel also SETTLES. A loose-dumped layer compacts down under traffic, so a driveway finished exactly to depth on day one will sit low within a season. Ordering slightly over, or planning to top it up after a few weeks, is normal rather than a mistake. Not included: excavation, a compacted sub-base, edging to stop the gravel migrating, and geotextile fabric underneath - which is what stops the stone disappearing into the soil over a few years and is far cheaper than replacing it. This assumes one rectangle at a uniform depth. Measure an irregular area as several rectangles and add the volumes.

Common questions

Tons or cubic yards — which do I order?

Whichever your supplier prices by, and you must ask, because the numbers are not close. The default job here is about 5.9 cubic yards and about 8.3 tons. Say '6' to a yard that sells by weight and you are 28 percent short; say '8' to one that sells by volume and you are 35 percent over, on a delivery that cannot go back. It is the single most expensive mistake available on this page.

What density should I use?

Ask for the figure for the material you are actually buying. Loose crushed gravel is commonly 1.35 to 1.5 tons per cubic yard, some crushed stone reaches 1.7, and compacted gravel is around 1.55. It is an input rather than a built-in constant because that range is real - a 20 percent difference in density is a 20 percent difference in what you pay, which is far too large to guess at.

How deep should a gravel driveway be?

About 4 inches is a common figure for the surface course, and that is what most people price. A driveway built properly is usually several layers, with a coarser base beneath - so the total excavation is considerably deeper than the layer you are calculating. A path or a decorative bed needs much less, often around 2 inches. If you are building a driveway from scratch rather than topping one up, work out each layer separately.

Should I order extra?

A little, yes - gravel settles. A loose-dumped layer compacts under traffic, so a driveway finished exactly to depth on day one sits noticeably low within a season. Ordering slightly over, or planning to top up after a few weeks once it has bedded in, is normal practice rather than a mistake. Bear in mind that bulk deliveries usually come in fixed increments anyway.

What is the fabric underneath for?

Geotextile fabric stops the stone migrating down into the soil, which is how a gravel drive quietly disappears over a few years and needs topping up repeatedly. It is not included in this calculation and it is far cheaper than the gravel it saves. Edging matters for the same reason in the other direction - it stops the stone travelling sideways into the lawn.

My area is not a rectangle.

Measure it as several rectangles, work out each volume, and add them. Do not use the overall bounding box of an L-shaped or curved area, because it includes ground you are not covering. For a curved edge, the usual approach is to measure the rectangle that contains it and accept a small over-order, which gravel tolerates better than most materials because the surplus is easy to spread elsewhere.

Take it further with AI

Copy this into ChatGPT or Claude with your own numbers filled in. It hands over the figures this calculator worked out, so the answer is built on real arithmetic instead of a guess.

I used the Gravel Calculator at https://www.bfcbrilliance.com/tools/gravel-calculator.

What I entered:
- Length (ft): ___
- Width (ft): ___
- Depth (in): ___
- Density (tons/cu yd): ___

What it calculated:
- Gravel needed: ___
- In cubic yards: ___
- In cubic feet: ___
- In pounds: ___
- Area covered: ___

Use those figures as given — they are already worked out, so please don't recalculate or estimate your own. Help me turn them into a plan: what to buy or do, in what order, roughly what it should cost, and the mistakes people most often make with this job.

Where the job touches structure, gas, or electrics, tell me to check local building code and whether a permit or a licensed trade is required.

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