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Construction & Home
Topsoil Calculator — Cubic Yards & 40 lb Bags of Dirt
Cubic yards for a bulk load, 40 lb bags for a small patch — sized for new beds, raised beds and leveling
Topsoil is sold two ways, and buying the wrong one is the fastest way to overspend or come up short. For anything bigger than a small bed, you order it in cubic yards from a landscape yard and they dump it from a truck. For a quick patch, a couple of raised beds, or filling a few low spots, you buy it in 40 lb bags at the hardware store. This calculator gives you both numbers from the same measurement so you can compare.
The math is volume, not area. Cubic yards = area (sq ft) × depth (ft) ÷ 27. Measure the bed's length and width in feet, multiply to get square feet, then multiply by the depth — but the depth has to be in feet too, so a 6-inch layer is 6 ÷ 12 = 0.5 ft. The ÷ 27 at the end converts cubic feet to cubic yards, because a cubic yard is 3 ft × 3 ft × 3 ft = 27 cubic feet.
Worked example: a bed 10 ft × 10 ft is 100 sq ft. At 6 inches deep that's 100 × 0.5 = 50 cubic feet, which is 50 ÷ 27 = 1.85 cubic yards. In 40 lb bags — each holds about 0.75 cubic feet — that's 50 ÷ 0.75 = 66.7, rounded up to 67 bags. You can see why 50 cu ft is a bulk-delivery job, not a bag job: 67 bags is a full pickup bed and a sore back.
How deep should it go? For a brand-new garden or flower bed, 3 to 6 inches of fresh topsoil is the usual range — 4 inches is a solid default. For laying or repairing a lawn, 2 to 4 inches over the existing grade is typical. To fill a raised bed, you measure the full inside depth (often 8 to 12 inches) because you're filling the whole box, though many gardeners blend topsoil with compost rather than using pure dirt.
A few things this tool does on purpose. It always rounds bags up — you can't buy two-thirds of a bag, and running out mid-project means a second trip. It lets you add a waste factor (5–15%) because beds settle, ground is never perfectly level, and a little spills off the shovel; 10% is a safe default. And it keeps topsoil math separate from mulch (also sold in bags and yards, but spread thin as a top dressing) and gravel (sold by the ton, not the yard, because stone is heavy) — mixing those constants is the classic landscaping mistake.
📖 See also: How to Calculate a Tip (and Split the Bill)
Calculator
Fill in the fields and click "Calculate" for instant results.
📰 Formula
• Area (sq ft) = length (ft) × width (ft) • Depth in feet = depth (in) ÷ 12 • Volume (cu ft) = area × depth (ft) • Cubic yards = cu ft ÷ 27 (1 cu yd = 27 cu ft) • 40 lb bag ≈ 0.75 cubic feet • Bags = ceil(cu ft ÷ 0.75) • With waste: multiply volume by (1 + waste % ÷ 100) before converting
📰 Formula
• Area (sq ft) = length (ft) × width (ft) • Depth in feet = depth (in) ÷ 12 • Volume (cu ft) = area × depth (ft) • Cubic yards = cu ft ÷ 27 (1 cu yd = 27 cu ft) • 40 lb bag ≈ 0.75 cubic feet • Bags = ceil(cu ft ÷ 0.75) • With waste: multiply volume by (1 + waste % ÷ 100) before converting
🧪 Worked examples
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Example 2
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Example 3
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Example 4
⚠️ Common mistakes
- Forgetting to convert depth from inches to feet (a 6-inch layer is 0.5 ft, not 6 ft).
- Calculating area only and forgetting topsoil is a volume — depth changes everything.
- Buying bags for a job that needs cubic yards (50+ cu ft is a bulk delivery, not 67 bags).
- Using gravel or mulch numbers — gravel is sold by the ton, mulch is spread thinner.
- Not adding a waste factor for settling, uneven ground and spillage.
💡 Tips
- Order 3–6 inches of topsoil for a new bed; 4 inches is a reliable default.
- For a raised bed, measure the full inside depth you want filled, not a thin layer.
- Add about 10% extra for settling and uneven ground so you don't make a second trip.
- Above roughly 1 cubic yard (about 36 bags), a bulk delivery is usually cheaper than bags.
- Topsoil for planting and fill dirt for leveling are different products — buy the right one.
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<iframe src="https://www.calcnimbus.com/embed/topsoil-calculator" width="100%" height="500" frameborder="0" style="border:1px solid #eee;border-radius:12px"></iframe>
❓ Frequently asked questions
How much topsoil do I need?
Multiply the bed's length and width in feet to get square feet, multiply by the depth in feet (inches ÷ 12), then divide by 27 for cubic yards. A 10 ft × 10 ft bed at 6 inches deep needs 100 × 0.5 ÷ 27 = 1.85 cubic yards.
How many 40 lb bags of topsoil are in a cubic yard?
A 40 lb bag holds about 0.75 cubic feet and a cubic yard is 27 cubic feet, so a yard takes 27 ÷ 0.75 = 36 bags. That's why anything over about a cubic yard is usually cheaper as a bulk delivery.
How deep should topsoil be for a new garden bed?
For a new flower or vegetable bed, 3 to 6 inches of topsoil is typical, with 4 inches a safe default. Deeper-rooted crops and raised beds want 8 to 12 inches of fill.
How much does a cubic yard of topsoil cover?
One cubic yard (27 cubic feet) covers about 108 square feet at 3 inches deep, 81 square feet at 4 inches, or 54 square feet at 6 inches. Coverage drops as the layer gets deeper because it's a fixed volume.
Should I buy topsoil in bags or by the cubic yard?
Bags make sense for small jobs under about a cubic yard (36 bags) where you don't want a delivery. For larger beds, lawns or fill, a bulk cubic-yard load from a landscape yard is far cheaper per cubic foot.
How much does a cubic yard of topsoil weigh?
Screened topsoil weighs roughly 2,000 to 2,700 pounds (about 1 to 1.35 tons) per cubic yard, and more when wet. Check your truck or trailer payload before hauling a full yard yourself.
What's the difference between topsoil and fill dirt?
Topsoil is the nutrient-rich upper layer used for planting beds and lawns. Fill dirt is cheaper subsoil used to raise grade or fill holes, and it isn't meant for growing plants — use this calculator's volume for either, but buy the right product.
How do I figure topsoil for a raised garden bed?
Measure the inside length, width and the full depth you want filled, then run the volume math. An 8 ft × 4 ft bed filled 10 inches deep is 8 × 4 × 0.833 = 26.7 cubic feet, or about 36 bags.
Is topsoil the same volume math as mulch?
The cubic-yard formula is the same, but the use is different. Mulch is spread thin (2 to 3 inches) as a top dressing, while topsoil is a thicker growing layer — and gravel is sold by the ton, not the yard, so don't reuse those numbers.