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Topsoil Calculator

Work out how much topsoil to order for a lawn, bed or grading job in cubic yards or cubic meters, with bag counts and an approximate weight.

Level: Grades 6–7

  • Common Core standard 6.G.A.2Find the volume of a right rectangular prism with fractional edge lengths by packing it with unit cubes of the appropriate unit fraction edge lengths, and show that the volume is the same as would be found by multiplying the edge lengths of the prism. Apply the formulas V = l w h and V = b h to find volumes of right rectangular prisms with fractional edge lengths in the context of solving real-world and mathematical problems.
  • Common Core standard 6.RP.A.3.dUse ratio reasoning to convert measurement units; manipulate and transform units appropriately when multiplying or dividing quantities.
Printable worksheet

Topsoil Calculator

Know the answer you need? Pick an input to work backward.

Inputs
Units
Area to cover

Printed on the bag. 0.75 ft³ and 1 ft³ are common.

Loose soil settles after it's spread and watered. Your supplier can say how much their soil settles.

1.33 g/cm³ (the same as t/m³) is a textbook figure for dry, medium-textured soil. Wet soil is heavier.

Result

Topsoil to order

2.72 yd³

Order about 2.72 cubic yards of topsoil, or 98 bags of 0.75 ft³.

Volume in cubic feet
73.33 ft³
Bags
98 bags
Approximate weight (dry)
3.04 tons
Approximate weight in pounds
6,089 lb
Area covered
200 ft²

See the step-by-step solution ↓

Step-by-step solution

  1. Multiply length by width to get the area

    20×10=200 ft²

  2. Multiply the area by the depth to get the volume, changing inches to feet first (÷ 12)

    200×412=66.666667 ft³

  3. Add 10% extra, because loose soil settles after it is spread

    66.666667×1+10100=73.333333 ft³

  4. Divide by 27 to get cubic yards, since a cubic yard is 3 ft × 3 ft × 3 ft

    73.33333327=2.716049 yd³

  5. Divide the cubic feet by the bag size. Round up, since you can't buy part of a bag

    73.3333330.75=97.7778

  6. Weight: multiply the volume in m³ by the bulk density, then by 1,000 to turn tonnes into kilograms

    2.076569×1.33×1,000=2,761.84 kg

Test yourself

20 quick questions built from this calculator's formula: work out results, predict what happens when an input changes, and work backward from an answer. Every answer comes with the working.

What this calculator does

Find out how much topsoil to order, whether you buy it by the truckload or by the bag. Topsoil goes down for new lawns, garden beds, low spots and the final slope of the ground around a house. Bulk suppliers sell it by the cubic yard or cubic meter. Garden centers sell it in bags. So the first job is turning your area and depth into a volume, then into the unit you're buying.

The calculator multiplies the area by the depth. It adds a little extra because soil settles after it's spread. Then it converts the result to cubic yards and cubic feet, or cubic meters and liters. You also get the number of bags of the size you choose. It gives an approximate weight from the soil's bulk density, too. That helps when a trailer or truck has a limit on what it can carry. Real topsoil varies a lot in moisture and makeup, so treat the weight as a rough guide.

Where it's used

Why this math matters outside the classroom:

  • New lawns. A homeowner covering 200 ft² with 4 in of topsoil needs 200 × 4 ÷ 12 ≈ 66.7 ft³, about 2.5 cubic yards before settling.
  • Raised garden beds. Gardeners filling a 4 × 8 ft bed 12 in deep need 32 ft³, which is 32 ÷ 27 ≈ 1.19 cubic yards.
  • Bag counts. Buying 1 ft³ bags for 27 ft³ of soil means exactly 27 bags, the same as one cubic yard.
  • Trailer loads. A landscaper checks that 1 m³ of soil at 1.33 t/m³, about 1.33 t, is within the trailer's rating.
  • Unit conversion. Students convert inches to feet and cubic feet to cubic yards, dividing by 12 and then by 27.

Grade level and standards: Grades 6–7; Common Core State Standards for Mathematics 6.G.A.2, 6.RP.A.3.d. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.

How to use it

  1. Choose US or metric units. Then choose whether you'll enter a length and width or a total area.
  2. Enter the area and the depth of soil you want once it has settled.
  3. If you're buying bags, set the bag size. Then set an allowance for settling, and the bulk density if you know it.
  4. Read the volume to order, the number of bags and the approximate weight.

What the inputs mean

Area
Add up the areas of irregular beds or lawn sections.
Depth of topsoil
A thin top dressing on an existing lawn is often under an inch. A new lawn commonly gets several inches, and vegetable beds more. Use the finished depth you want. The settling allowance adds the extra.
Bag size
Printed on the bag. 0.75 ft³ and 1 ft³ are common.
Extra for settling and grading
Loose, freshly delivered soil settles once it's raked, rolled and watered. The allowance raises the order to cover that, plus small losses while you level it. Your supplier can say how much their soil usually settles.
Soil bulk density (for weight)
Bulk density is how much a set volume of soil weighs, counting the air gaps between grains. 1.33 g/cm³ is a textbook value for dry, medium-textured soil that's about half air gaps. Moist delivered topsoil is heavier. Soil rich in organic matter (rotted plant material) is lighter.

Formula and method

volume = area × depth × (1 + extra ÷ 100)
cubic yards = cubic feet ÷ 27
bags = round up(volume ÷ bag size)
weight (kg) = volume (m³) × bulk density (g/cm³) × 1,000

In the formulas, extra is the settling allowance as a percent. Depth in inches is divided by 12 to get feet, or centimeters by 100 to get meters. That way the volume comes out in cubic feet or cubic meters. A cubic yard is 3 × 3 × 3 = 27 cubic feet, and a cubic meter is 1,000 liters.

A bulk density in g/cm³ is the same number as tonnes per cubic meter. So multiplying the volume in cubic meters by it gives tonnes. For US units, the calculator converts with the exact factors 1 ft³ = 0.028316846592 m³ and 1 lb = 0.45359237 kg. It reports US short tons of 2,000 lb.

Worked example

A new lawn area measures 20 ft by 10 ft and needs 4 in of topsoil, with 10% extra for settling, using 0.75 ft³ bags and the default density.

  1. Area: 20 × 10 = 200 ft².
  2. Volume: 200 × 4 ÷ 12 = 66.6667 ft³, then × 1.10 = 73.3333 ft³.
  3. Cubic yards: 73.3333 ÷ 27 = 2.716 yd³.
  4. Bags: 73.3333 ÷ 0.75 = 97.78, rounded up to 98 bags.
  5. Weight: 73.3333 ft³ = 2.0766 m³ × 1.33 × 1,000 = 2,761.84 kg, about 6,089 lb or 3.04 tons.

Result: Order about 2.72 cubic yards of topsoil, or 98 bags of 0.75 ft³, weighing roughly 3 tons dry.

Understanding the result

Bulk suppliers usually sell in whole or half cubic yards. So round the volume up to what they deliver. For more than a cubic yard or two, bulk delivery is usually far less work than carrying bags.

A cubic yard of soil can weigh well over a ton. That's more than many small trucks and trailers are rated to carry. Check the payload (the weight your vehicle can carry) before hauling it yourself.

Assumptions and limitations

  • The area is flat and filled to an even depth.
  • The settling allowance covers packing down and small losses while leveling.
  • The weight uses a dry bulk density. Moisture adds weight.
  • Low spots, slopes and uneven ground need more soil than an even layer over the area.
  • Bags labelled by weight instead of volume need converting with the volume printed on the bag.
  • Real density varies with texture, organic matter, screening and moisture. So the weight is approximate.

Frequently asked questions

How much area does a cubic yard of topsoil cover?

A cubic yard is 27 ft³. It covers 81 ft² at 4 in deep, 108 ft² at 3 in, 162 ft² at 2 in and 324 ft² at 1 in, before any settling allowance.

How many bags make a cubic yard?

Divide 27 ft³ by the bag size: 36 bags of 0.75 ft³, 27 bags of 1 ft³ or 18 bags of 1.5 ft³. At that point, bulk delivery is often cheaper and easier.

How much does a cubic yard of topsoil weigh?

At a dry bulk density of 1.33 g/cm³, a cubic yard is about 1,017 kg, or roughly 2,240 lb. Moist soil can weigh quite a bit more. So ask the supplier for their figure when weight matters.

How deep should topsoil be for a new lawn?

It depends on the soil beneath, the grass and local practice. Extension services (local university advice offices) and seed suppliers give guidance for each region. Enter whatever depth you choose, and the calculator will size the order.

Sources

How this calculator is checked

Method: Prism volume (area × depth) with exact US–metric factors; weight from dry bulk density (default 1.33 g/cm³ from the USDA NRCS bulk density indicator sheet). The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.

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