Area 1
Advanced options
Splits your order into each component.
Loose soil drops when watered in.
Check the bag — weight-sold volumes vary.
Affects weight and truck loads only.
This topsoil calculator works out how much soil you need in cubic yards and bags — with a settling allowance, and the option to split your order into topsoil, compost and amendments for a proper garden blend.
The short answer
Topsoil volume is area × depth ÷ 27, with depth in feet. Or the shortcut: (square feet × depth in inches) ÷ 324 = cubic yards.
A 1,000 ft² lawn at 4 inches needs 12.3 cubic yards before settling, or about 14 with a 15% allowance. One cubic yard covers 81 square feet at 4 inches.
On this page
How to use this topsoil calculator
Enter your area and depth and the calculator returns cubic yards, bags, weight, truck loads and cost. Four modes:
- Lawn or bed — rectangular areas, the common case
- Raised bed — length, width, fill depth and how many beds
- Circle — round beds and tree rings
- Known area — you’ve already worked out the square footage
Two settings under Advanced options change the answer more than anything else. The settling allowance covers soil dropping once it’s watered in — the single most common reason a bed ends up short. The soil blend splits your total into topsoil, compost and amendments, so you know how much of each to actually order.
The topsoil formula
Cubic yards = Length (ft) × Width (ft) × Depth (ft) ÷ 27
Or working straight from inches:
Cubic yards = (Area in ft² × Depth in inches) ÷ 324
The 324 is just 27 cubic feet per yard × 12 inches per foot. It saves converting depth, and it’s the version most landscapers use in their heads.
Worked example — 30 × 20 ft area at 4 inches
307 bags is why nobody buys bagged soil at this scale — that’s roughly nine pallets.
Settling — the step most calculators skip
Loose soil is full of air. Freshly delivered topsoil, and bagged garden mixes especially, arrive fluffed up. The first heavy watering collapses those air pockets and the level drops.
On a lawn this shows up as low spots. In a raised bed it’s more dramatic — a 12 inch bed filled to the brim commonly settles two to three inches within a few weeks, which is exactly the complaint that sends people back to the garden centre.
| Situation | Allowance | Why |
|---|---|---|
| Filling a hole or trench, compacted | 0% | You’re compacting as you go |
| Firm bulk topsoil, screened | 10% | Dense material, modest settling |
| Standard bulk topsoil on a lawn | 15% | The general-purpose figure |
| Raised beds and bagged mixes | 25% | High organic content, very fluffy, settles hard |
The alternative to over-ordering is filling the bed, watering it thoroughly, waiting a few weeks, then topping up. That’s arguably the better approach for raised beds — you get an accurate final level and you’re adding fresh compost anyway. It just means two trips instead of one.
How deep should topsoil be?
| Application | Depth | yd³ per 1,000 ft² |
|---|---|---|
| Lawn top dressing over aeration | ¼–½ in | 0.8–1.5 |
| Lawn repair, filling low spots | 1–2 in | 3.1–6.2 |
| Laying sod | 2–4 in | 6.2–12.3 |
| New lawn from seed | 4–6 in | 12.3–18.5 |
| Flower beds | 6–8 in | 18.5–24.7 |
| Vegetable beds | 8–12 in | 24.7–37.0 |
| Raised beds | 10–18 in | 30.9–55.6 |
| Trees and shrubs | 12–18 in | 37.0–55.6 |
Laying topsoil straight onto compacted ground creates a distinct layer boundary. Roots reach it, hit the hardpan and turn sideways, and water perches on top of the interface instead of draining. Rototill the top inch or two of the existing ground before you spread, so the profiles blend.
For lawn top dressing, aerate first and keep it thin — under half an inch. Burying existing grass under a thick layer smothers it.
How much does a cubic yard of topsoil cover?
| Depth | Per cubic yard | Per 0.75 cu ft bag | yd³ per 100 ft² |
|---|---|---|---|
| ½ inch | 648 ft² | 18 ft² | 0.15 |
| 1 inch | 324 ft² | 9 ft² | 0.31 |
| 2 inches | 162 ft² | 4.5 ft² | 0.62 |
| 3 inches | 108 ft² | 3 ft² | 0.93 |
| 4 inches | 81 ft² | 2.3 ft² | 1.24 |
| 6 inches | 54 ft² | 1.5 ft² | 1.85 |
| 8 inches | 40 ft² | 1.1 ft² | 2.47 |
| 12 inches | 27 ft² | 0.75 ft² | 3.70 |
Bag sizes, and the 40 lb puzzle
Search how many bags of topsoil make a cubic yard and you’ll find 27, 36 and 54 all stated confidently. All three are correct — for different bags.
Bags labelled by volume — 0.75, 1, 1.5 or 2 cu ft — contain exactly what they say. Divide 27 by the bag size and you have your answer.
Bags labelled by weight — the common 40 lb bag — do not have a fixed volume. Dry soil is lighter per cubic foot, so 40 lb of dry soil is more soil than 40 lb of wet soil. At typical moisture a 40 lb bag holds about half a cubic foot, which is where “54 bags per yard” comes from. Buy the same bag after a rainy week and you’ll get noticeably less.
| Bag | Volume | Bags per yd³ | Covers at 4 in |
|---|---|---|---|
| 40 lb (sold by weight, moist) | ≈0.5 ft³ | 54 | 1.5 ft² |
| 0.75 cu ft | 0.75 ft³ | 36 | 2.3 ft² |
| 1 cu ft | 1.0 ft³ | 27 | 3 ft² |
| 1.5 cu ft | 1.5 ft³ | 18 | 4.5 ft² |
| 2 cu ft | 2.0 ft³ | 14 | 6 ft² |
If a bag only shows a weight, ask the supplier for the volume or assume half a cubic foot and expect to be slightly over. Comparing a 40 lb bag against a 1 cu ft bag on price alone is meaningless — you’re comparing different quantities.
Filling raised beds
| Bed size | Depth | Volume | +25% settling | 1.5 cu ft bags |
|---|---|---|---|---|
| 4 × 4 ft | 12 in | 0.59 yd³ | 0.74 yd³ | 14 |
| 4 × 8 ft | 12 in | 1.19 yd³ | 1.48 yd³ | 27 |
| 4 × 8 ft | 18 in | 1.78 yd³ | 2.22 yd³ | 40 |
| 2 × 8 ft | 18 in | 0.89 yd³ | 1.11 yd³ | 20 |
| 3 × 6 ft | 12 in | 0.67 yd³ | 0.83 yd³ | 15 |
Two things worth knowing before you fill a deep bed. Most vegetables root in the top 8 to 12 inches, so a bed deeper than that doesn’t need premium mix all the way down — you can fill the lower third with cheaper bulk topsoil and reserve the good stuff for the root zone.
And if the bed sits on soil rather than a hard surface, you don’t need to fill the frame from a solid base. Loosening the ground underneath gives roots somewhere to go and reduces how much you buy.
Soil blends worth knowing
| Blend | Recipe | Best for |
|---|---|---|
| Garden mix | 50% topsoil, 50% compost | General beds, borders, most vegetables |
| Raised bed mix | 60% topsoil, 30% compost, 10% aeration | Raised beds — the aeration keeps it from compacting |
| Mel’s Mix | ⅓ compost, ⅓ peat or coir, ⅓ vermiculite | Square foot gardening — excellent, expensive, no native soil |
| Lawn starter | 70% topsoil, 30% coarse sand | New turf on heavy clay, where drainage is the problem |
Select a blend in the calculator and it splits your total into each component, in cubic yards and bags. That’s the number you actually need when ordering — most people work out the total and then guess at the split.
Much of what landscape yards sell as topsoil is stripped construction or agricultural site soil — fine as a growing medium under turf, but often dense and low in organic matter. It’s a base ingredient, not a finished product.
For anything you intend to grow food in, blend it roughly half and half with compost or buy a pre-mixed garden soil. The premium over plain topsoil is small and it makes a visible difference in the first season.
Topsoil, garden mix or fill dirt?
Screened topsoil
Lawns and general use
Sifted to remove rocks and clumps. The default choice for laying turf, seeding and levelling. Blend with compost for planting beds.
Garden or compost mix
Anything you’ll grow in
Topsoil already blended with compost. Costs $10–$25 more per yard and is worth it for vegetables, perennials and raised beds.
Fill dirt
Bulk and grading only
Unscreened subsoil. Cheap, used to build up levels and fill holes. Not a growing medium — put topsoil over it.
Bags or bulk?
The crossover is around 1.5 to 2 cubic yards. Below that, bags usually win once you count delivery fees and minimum orders. Above it, bulk is dramatically cheaper and far less handling.
| Item | Typical US price |
|---|---|
| Bulk screened topsoil, per yard | $25–$50 |
| Bulk garden mix, per yard | $40–$70 |
| Bagged topsoil, 0.75–1 cu ft | $4–$8 per bag |
| Bagged equivalent, per yard | $150–$290 |
| Delivery | $50–$100 per load |
Put plainly: a cubic yard costs roughly $35 in bulk against $200 or more in bags. The bags win only when the delivery fee outweighs the difference, which is why the crossover sits so low.
Topsoil ordering mistakes to avoid
- Skipping the settling allowance. Raised beds especially — 25% is not excessive.
- Comparing 40 lb bags on price. They have no fixed volume; compare cubic feet.
- Spreading over compacted ground. Break up the subgrade or you build a hardpan boundary.
- Top dressing too thick. Over half an inch smothers existing grass.
- Using pure topsoil in vegetable beds. It’s a base ingredient, not a finished growing medium.
- Buying fill dirt to plant in. It’s subsoil, and nothing will thrive in it.
- Ordering bags above two yards. That’s over 100 bags, several pallets and five times the price.
Frequently asked questions
How much topsoil do I need?
Multiply your area in square feet by the depth in inches and divide by 324 to get cubic yards. A 1,000 ft² lawn at 4 inches needs 12.3 cubic yards, or about 14 with a 15% settling allowance.
How many bags of topsoil in a cubic yard?
It depends on the bag. 36 bags of 0.75 cu ft, 27 of 1 cu ft, 18 of 1.5 cu ft, or 14 of 2 cu ft. A 40 lb bag sold by weight holds roughly half a cubic foot at typical moisture, so about 54 per yard — but that varies because dry soil is lighter per cubic foot than wet.
How much area does a yard of topsoil cover?
324 square feet at 1 inch deep, 162 at 2 inches, 81 at 4 inches, 54 at 6 inches and 27 at 12 inches. Coverage is 324 divided by the depth in inches.
How much does a yard of topsoil weigh?
Around 2,200 lb at typical moisture, within a range of 2,000 lb dry to 2,700 lb wet. That’s roughly one to one and a third tons. A half-ton pickup can legally carry about half a cubic yard.
How deep should topsoil be for a new lawn?
4 to 6 inches for seeding, or 2 to 4 inches for laying sod over prepared ground. Rototill the top inch or two of the existing subgrade first so the new soil blends in rather than sitting on a compacted layer.
How much soil do I need for a 4×8 raised bed?
At 12 inches deep, 32 cubic feet or 1.19 cubic yards — about 1.48 yards once you allow 25% for settling. That’s roughly 27 bags at 1.5 cu ft each. At 18 inches deep it rises to 2.22 yards including settling.
Why does my raised bed soil keep sinking?
Garden soil is full of air pockets when loose. The first heavy watering collapses them and the level drops 20–25% — two to three inches in a 12 inch bed. Organic matter also breaks down over the season. Either order 25% extra up front, or fill, water thoroughly, wait a few weeks and top up.
What’s the difference between topsoil and garden soil?
Topsoil is screened mineral soil — a base ingredient. Garden soil is topsoil already blended with compost, giving it organic matter, nutrients and better structure. Topsoil is fine under turf; use garden mix, or blend your own half and half with compost, for anything you’re growing.
What is the best soil mix for a raised bed?
A common blend is 60% topsoil, 30% compost and 10% aeration material such as perlite or bark fines. A simpler 50/50 topsoil and compost mix works well too. Mel’s Mix — equal thirds compost, peat or coir, and vermiculite — is excellent for intensive small beds but costs considerably more.
Is it cheaper to buy topsoil in bags or bulk?
Bulk is dramatically cheaper — roughly $25–$50 per cubic yard against $150–$290 for the bagged equivalent. Bags only win below about 1.5 to 2 cubic yards, where the delivery fee and minimum order outweigh the price difference.
Can I put topsoil over existing grass?
Only very thinly. Top dressing at a quarter to half an inch over an aerated lawn works well and improves the soil gradually. Anything thicker smothers the grass. To replace a lawn entirely, kill or strip the existing turf first rather than burying it.
Can I use this topsoil calculator in metric?
Yes. Switch the header toggle to m / mm and enter dimensions in metres and millimetres. Results show cubic yards, cubic feet, cubic metres and bag counts together.
Sources and method
- Volume calculations are geometric and exact; conversions use NIST factors
- Soil weights compiled from multiple landscape supply references and reported as a range, because moisture content moves them substantially
- Bag volumes reflect standard US retail sizes; bags labelled by weight rather than volume vary with moisture
- Depth guidance follows published horticultural extension recommendations
- Pricing ranges are indicative US figures and vary by region and season
Related calculators
Cubic Yards CalculatorVolume and weight for any material
Gravel CalculatorYards and tons with compaction
Square Footage CalculatorMeasure irregular beds first
Compost CalculatorHow much to work into a bed
Raised Bed Soil CalculatorFill volume and blend by bed size
How this topsoil calculator works out its numbers
Volume uses standard geometric formulas with all inputs normalised to feet, then divided by 27 for cubic yards. The settling allowance is applied on top of measured volume, because the depth you enter is the finished level you want after the soil has settled. Bag counts divide total cubic feet by the selected bag volume and round up. Bulk quantities round to the nearest half yard, which is how most suppliers sell.
Blend ratios split the total by volume, not weight, and report each component in cubic yards, cubic feet and bags — since compost and topsoil are usually bought separately.
Weight uses the moisture setting you choose, from 2,000 lb per cubic yard dry to 2,700 lb wet. This is the figure with the widest genuine variation in the calculator, and it affects only weight and truck loads, not volume. Truck load figures apply both a volume and a payload limit and report whichever is reached first.