How Much Fill Dirt or Topsoil Do I Need? A Simple Yardage Guide

Short answer: length times width times depth, all in feet, divided by 27, equals cubic yards. That one formula covers every fill dirt and topsoil question. A 10 by 20 foot area needing 6 inches of topsoil is 10 x 20 x 0.5 = 100 cubic feet, divided by 27 is about 3.7 yards. Add roughly ten percent for settling and compaction, and if you would rather skip the math entirely, call with your measurements and we will figure it with you before you order.

"How many yards do I need?" is probably the question we answer most often on the phone, and it deserves a straight, calculator-free answer. Here is the math, some worked examples for the projects people around here actually do, and the practical stuff the formula does not tell you.

The only formula you need

Material is sold by the cubic yard, and a cubic yard is a 3 x 3 x 3 foot cube, which is 27 cubic feet. So:

Length (ft) x Width (ft) x Depth (ft) / 27 = cubic yards

The only trap is the depth unit. Depth is usually planned in inches, and the formula wants feet, so divide the inches by 12 first: 3 inches is 0.25 feet, 6 inches is 0.5 feet. That conversion is where most driveway math goes wrong, and it goes wrong by a factor that either strands you short or buries you in extra dirt.

Worked examples

Topsoil for a lawn repair

Reseeding a 30 x 40 foot section of yard with 4 inches of screened topsoil: 30 x 40 x 0.33 = about 400 cubic feet, divided by 27 is roughly 15 yards. That is a full truckload territory, which usually beats bagged material on price by a wide margin.

Filling a low spot

A soggy low area about 15 x 15 feet that needs to come up 8 inches on average: 15 x 15 x 0.67 = about 150 cubic feet, or roughly 5.5 yards of fill. Low spots are rarely uniform, so measure the deepest point, halve it for an average, and round up. If the low spot is wet because water keeps arriving, fill alone will not fix it; see our drainage work before buying dirt twice.

Topping a gravel driveway

A 200 foot drive, 10 feet wide, taking 2 inches of fresh 21AA: 200 x 10 x 0.17 = about 330 cubic feet, or a bit over 12 yards. Driveway stone questions branch fast from there, and our driveway cost guide and material comparison cover the rest.

Backfilling around a new foundation or septic

Trench and foundation backfill is tougher to eyeball because the shape is irregular. Estimate it as a long box: trench length times average width times average depth, then add the ten percent. Better yet, this is a case where letting the contractor doing the work supply the material keeps the estimate and the responsibility in one place.

Odd shapes and slopes

Real yards are not rectangles. For an odd-shaped area, break it into a few rough rectangles, run the formula on each, and add them up; close is good enough at this scale. For a slope you are building up, depth varies from nothing at the top to the full lift at the bottom, so use half the maximum depth as your average and the formula stays honest.

Fill dirt or topsoil? Pay for the right one

The rule is simple: fill for depth, topsoil for the finish. Fill dirt, usually sand or clean subsoil around here, is structural material for raising grade and filling holes. Screened topsoil is growing material for the top few inches under grass and gardens. Building up a foot of grade with topsoil wastes money; finishing a lawn with fill sand wastes seed. On bigger regrades, buy fill for the body and a topsoil lift for the skin.

Yards, tons, and truckloads

Pits and haulers switch between yards and tons freely, which confuses everyone. Dirt and stone weigh very roughly a ton to a ton and a half per cubic yard depending on the material and how wet it is, so the two units describe the same pile in different languages. Trucks are limited by weight before volume: our tri-axle hauls in the mid-teens of tons, which works out to roughly ten or a dozen yards of most materials per load. For the lawn examples above, that means one load usually covers it; for a long driveway, plan on multiples.

Three practical tips before you order

Round up, slightly. Material settles and compacts, so an exact-to-the-inch order finishes short. Ten percent extra is the working rule.
Plan the drop. A tri-axle needs room to maneuver and overhead clearance to raise the bed. Pick a dump spot close to the work: moving a pile twice by wheelbarrow is the most expensive trucking there is.
Say what the material is for. Tell the supplier the job, not just the yardage. "Fill under a shed pad" and "topsoil for seeding" get you the right material the first time.

Or just call us with the measurements

We deliver screened topsoil, fill sand and dirt, gravel, and stone by the tri-axle load across Hale, Tawas, and the surrounding counties, usually within the week. Give us the length, width, and depth over the phone and we will do the yardage math with you, tell you honestly how many loads it is, and quote a delivered price. Details on our trucking and material delivery page, or request a quote and we will call you back within 24 hours.

Quick questions

What is the difference between fill dirt and topsoil?

Fill dirt is structural: sand or subsoil used to raise grade and fill holes, with nothing in it you want growing. Topsoil is the good stuff for the top few inches where grass and gardens live. Fill for depth, topsoil for the finish; paying topsoil prices for a fill job wastes money.

How many yards fit in one dump truck load?

It depends on the truck and the material, because weight limits govern before volume does. A tri-axle hauls in the mid-teens of tons, which works out to roughly ten or a dozen yards of most materials. Tell us the yardage and we will tell you the loads.

Should I order extra material?

A little, yes. Dirt compacts and settles, so a load calculated to the exact inch usually finishes short. Adding roughly ten percent for compaction is the working rule, and we can sanity-check your numbers over the phone before you order.

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