Topsoil Calculator
Buying too much topsoil means hauling heavy bags back to the store. Buying too little means your lawn or garden won't thrive. This calculator matches your project dimensions and desired depth to the exact cubic yardage, bag count, and budget you need.
Quick Reference
Recommended Topsoil Depth
Choosing the right topsoil depth depends on your application. Too little topsoil won't support healthy plant growth. Too much can cause drainage problems and waste money. Use these recommended depths for best results:
| Application | Recommended Depth | Cubic Yards per 100 sq ft |
|---|---|---|
| New Lawn (Seed) | 4-6 inches | 1.48 - 2.22 |
| New Lawn (Sod) | 2-4 inches | 0.74 - 1.48 |
| Flower Beds | 6-8 inches | 2.22 - 2.96 |
| Vegetable Garden | 8-12 inches | 2.96 - 4.44 |
| Raised Beds (fill) | Full height (8-12") | 2.96 - 4.44 |
| Lawn Topdressing | 0.25-0.5 inches | 0.09 - 0.19 |
Grass roots need at least 4 inches of quality topsoil to establish properly. Laying sod on 1 inch of topsoil over compacted fill is why many new-construction lawns struggle.
Topsoil Types Compared
Different soil types serve different purposes. Here is a comparison to help you choose the right one for your project:
| Type | Weight (lbs/ft³) | Coverage per yd³ | Best For | Typical Price/yd³ |
|---|---|---|---|---|
| Standard Topsoil | 80 | 100 sq ft @ 3" | Lawns, general landscaping | $25-$40 |
| Screened Topsoil | 75 | 100 sq ft @ 3" | New lawns, overseeding | $30-$50 |
| Garden Soil Blend | 65 | 100 sq ft @ 3" | Garden beds, flower beds | $35-$55 |
| Compost-Amended | 70 | 100 sq ft @ 3" | Vegetable gardens, raised beds | $40-$60 |
| Potting Mix | 50 | 100 sq ft @ 3" | Containers, seed starting | $30-$50 |
| Raised Bed Mix | 55 | 100 sq ft @ 3" | Raised beds, planters | $35-$55 |
Topsoil Coverage Chart
Use this quick reference chart to convert between cubic feet, cubic yards, and bags:
| Cubic Feet | Cubic Yards | Bags (0.75 ft³) | Coverage @ 4" Depth |
|---|---|---|---|
| 10 | 0.37 | 14 | 30 sq ft |
| 20 | 0.74 | 27 | 60 sq ft |
| 30 | 1.11 | 40 | 90 sq ft |
| 40 | 1.48 | 54 | 120 sq ft |
| 54 | 2.00 | 72 | 162 sq ft |
| 100 | 3.70 | 134 | 300 sq ft |
Bulk vs Bagged Topsoil
Bulk topsoil is almost always cheaper per cubic yard than buying bags, but bagged topsoil has its place. Here is a cost comparison to help you decide:
| Volume | Bulk Cost ($35/yd³) | Bagged Cost ($6/bag) | Savings with Bulk |
|---|---|---|---|
| 0.5 yd³ | $17.50 | $108 (18 bags) | $90.50 |
| 1 yd³ | $35.00 | $216 (36 bags) | $181.00 |
| 2 yd³ | $70.00 | $432 (72 bags) | $362.00 |
| 3 yd³ | $105.00 | $648 (108 bags) | $543.00 |
Bulk delivery tip: Most suppliers charge $50-$100 for delivery, but it is still cheaper than bags for projects over 1 cubic yard. Ask about free delivery thresholds - many suppliers offer free delivery on orders of 2+ yards.
How to Use This Calculator
Step 1: Choose your area shape - Rectangle for standard beds, Circle for tree rings, or Total Area if you already know the square footage.
Step 2: Enter dimensions. For rectangle, enter length and width. For circle, enter diameter. For total area, enter square footage directly.
Step 3: Set depth using the preset buttons (4"-12") or enter a custom value.
Step 4: Select soil type and enter pricing. The calculator shows bulk vs bag cost comparison.
Step 5: Results show instantly - cubic yards, bags, weight, coverage, and cost comparison with savings.
Topsoil Formula
The calculator converts your project dimensions into topsoil volume and cost:
- Volume (ft³) = Length (ft) x Width (ft) x (Depth in inches / 12)
- Volume (yd³) = Volume (ft³) / 27
- Bags Needed = Volume (ft³) / Bag Size (typically 0.75 ft³)
- Weight = Volume (yd³) x Density (varies by soil type)
- Bulk Cost = Volume (yd³) x Price per Cubic Yard
- Bag Cost = Bags Needed x Price per Bag
- With Settling = Total x (1 + Settling Factor / 100)
The density dropdown automatically adjusts weight calculations based on your soil type. Standard topsoil is heavier than potting mix, while compost-amended blends fall in between.
Worked Example: 4x8 Raised Bed
Let us calculate topsoil for a 4 ft x 8 ft raised bed at 12 inches deep using standard topsoil (80 lb/ft³) with 10% settling.
Step 1: Calculate volume:
Cubic Yards = 32 / 27 = 1.19 yd³
Step 2: Calculate weight:
(That is more than a standard pickup truck can safely carry)
Step 3: Calculate cost at $35/yd³:
Bags = 32 / 0.75 = 43 bags x $6 = $258 (bagged)
Total: 1.19 cubic yards of topsoil at $41.65 bulk vs $258 bagged. Use the calculator above to model your own project.
Tips and Common Mistakes
Best Practices
- Add 10-15% extra for settling. Topsoil compacts after watering and time.
- Test your soil first - a $15 soil test tells you what amendments you actually need.
- Check delivery access - a dump truck needs 12+ feet of clearance and firm ground.
- Have a spreading plan - topsoil is heavy; you do not want to move it twice.
- Order slightly more than calculated - it is cheaper to have a little extra than not enough.
Avoid This
- Buying too little: Running out mid-project means a second delivery fee or uneven results.
- Using fill dirt for growing: Fill dirt has no nutrients and compacts heavily. Use topsoil for plants.
- Ignoring settling: A 4-inch layer settles to 3-3.5 inches. Order 10-15% more.
- Skipping soil test: You may already have good soil - or need specific amendments.
- Spreading on wet soil: Work topsoil into soil when both are dry to avoid compaction.
Frequently Asked Questions
At 4 inches deep, a 10x10 area needs about 33 cubic feet, which equals 44 bags of 0.75-cubic-foot topsoil or 33 bags of 1-cubic-foot topsoil. That is roughly 1.23 cubic yards.
For seeding, use 4-6 inches of topsoil. For sod, 2-4 inches is sufficient. Grass roots need at least 4 inches of quality soil to establish properly.
Dry topsoil weighs about 1,800-2,200 lbs per cubic yard (67-81 lbs per cubic foot). Moist topsoil weighs 2,200-2,600 lbs per cubic yard. Saturated topsoil can reach 2,800-3,000 lbs per cubic yard.
A 40lb bag of topsoil contains approximately 0.5 to 0.75 cubic feet, depending on moisture content and soil density. Use 0.75 cubic feet as a planning average.
Topsoil is the nutrient-rich upper layer of soil, screened and suitable for growing plants. Fill dirt is subsoil used for grading and backfilling where plant growth is not a concern.
Measure length x width x depth in feet, then divide by 27 for cubic yards. A standard 4x8 raised bed at 12 inches deep needs about 1.19 cubic yards or 32 cubic feet of topsoil.
Yes, bulk topsoil is significantly cheaper for projects over 2 cubic yards. Bulk costs $25-55 per cubic yard, while bagged topsoil costs $150-200 per cubic yard equivalent.