Rock Calculators turns the measurements of a bed, path, patio, slope or wall into the numbers a stone yard asks for: cubic yards, tons and bags. It also estimates the weight of single pieces of stone, like a boulder or a granite slab, from their dimensions.
How we work out the numbers
Loose rock is calculated the same way on every page: area × depth gives volume, volume ÷ 27 gives cubic yards, and cubic yards × the rock’s weight per yard gives tons. Solid stone (boulders, slabs, flagstone, wall stone) uses the volume of the piece times the density of the stone, taken from typical specific gravities for each rock type.
The depth suggestions follow one simple rule: spread loose rock about twice as deep as the average stone is wide, and never less than 2 inches. Each page explains where its numbers come from.
Real rock varies. Stone type, size, shape, moisture and the quarry it came from all change the weight of a cubic yard, and real boulders are never perfect shapes. That is why every result is an estimate, and why we suggest confirming quantities with the supplier who will deliver your rock.
What we don’t do
- We don’t sell rock or take commissions from suppliers.
- We don’t publish national price averages. Rock and delivery prices depend on how far you are from the quarry, so our cost guide shows you how to build a budget from your own local quotes.
- We don’t give engineering advice. Retaining walls, riprap in streams and anything holding back a slope may need a professional design and a permit.
Corrections
If a number looks wrong, please tell us through the contact page. We check and correct pages when readers point out mistakes.