Loam Calculator
Loam is the gold standard for lawns and gardens, but your project is measured in square feet and depth. This calculator converts your coverage area into cubic yards, tons, bags, and total cost across 4 common loam and soil types.
Quick Reference
Soil Types Compared
Different loam and soil types serve different purposes. Here is a comparison to help you choose the right one for your project:
| Type | Weight (lbs/ft³) | Tons/Yard³ | Best For | Typical Price/yd³ |
|---|---|---|---|---|
| Screened Loam | 80 | 1.08 | Lawn top-dressing, general landscaping | $20-$30 |
| Garden Soil Blend | 85 | 1.15 | Vegetable gardens, raised beds | $30-$40 |
| Topsoil/Loam Mix | 75 | 1.01 | New lawn installation, leveling | $15-$25 |
| Premium Black Dirt | 82 | 1.11 | Flower beds, premium landscaping | $35-$45 |
Loam Depth Guide
Depth depends on your project. Too thin and it will not support healthy growth. Too deep and you waste money.
| Depth | Best For | Sq Ft per yd³ (Screened Loam) |
|---|---|---|
| 1-2 inches | Lawn top-dressing, overseeding | 162-324 sq ft |
| 3-4 inches | Vegetable garden prep, leveling | 81-108 sq ft |
| 6 inches | New lawn, flower beds | 54 sq ft |
| 8-12 inches | Raised beds, deep amendment | 27-40 sq ft |
Loam vs Topsoil: Which Do You Need?
Loam and topsoil serve different purposes. Here is when to use each:
Use Loam When
- Top-dressing an existing lawn
- Preparing a new garden bed
- Creating a seed-starting mix
- Amending compacted or poor soil
- Filling raised garden beds
Use Topsoil When
- Filling large excavated areas
- Building up grade or leveling
- Establishing a new lawn from seed
- General backfill around foundations
- Budget-conscious large area coverage
How to Use This Calculator
Step 1: Choose your area shape - Rectangle for standard beds and lawns, Circle for tree wells or round planters, 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 (2"-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, cubic feet, weight in tons, area, coverage per yard, cost breakdown, and total.
Loam Formula
The calculator converts your project dimensions into loam volume and cost:
- Rectangle: Area = Length x Width
- Circle: Area = Pi x (Diameter / 2)²
- Volume (ft³) = Area (ft²) x (Depth in inches / 12)
- Volume (yd³) = Volume (ft³) / 27
- Weight (tons) = Volume (ft³) x Density (varies by type) / 2,000
- Bags (2 cu ft) = Volume (ft³) / 2
- Coverage per yd³ = 27 / (Depth in inches / 12)
- Bulk Cost = Volume (yd³) x Price per Cubic Yard
- Bag Cost = Bags x Price per Bag
Density varies by soil type. Garden soil blend is the densest at 85 lbs/ft³, while topsoil/loam mix is lighter at 75 lbs/ft³. The soil type dropdown adjusts the density automatically.
Worked Example: 20x15 Garden Bed
Let us calculate loam for a 20 ft x 15 ft garden bed at 8 inches deep using screened loam (80 lb/ft³) with 10% waste.
Step 1: Calculate volume:
Volume = 300 x (8 / 12) = 200 ft³
Cubic Yards = 200 / 27 = 7.41 yd³
Step 2: Calculate weight:
Tons = 16,000 / 2,000 = 8 tons
Step 3: Calculate cost at $25/yd³:
Bags = 200 / 2 = 100 bags x $6 = $600
Total: 7.41 cubic yards of screened loam at $185.25 bulk vs $600 bagged. Use the calculator above to model your own project.
Tips and Common Mistakes
Best Practices
- Test your soil first - Know your existing soil type before ordering loam to get the right blend.
- Order 10% extra - Loam settles and shrinks; extra covers uneven spots and low areas.
- Spread evenly - Use a rake to distribute loam uniformly across the area for consistent growth.
- Water after spreading - Lightly water loam to help it settle and bond with existing soil.
- Compare bulk vs bags - Bulk is almost always cheaper for projects over 1 cubic yard.
Avoid This
- Using pure topsoil for gardens: It may compact and lack the nutrients and drainage that loam provides.
- Skipping soil testing: pH and nutrient imbalances can waste your loam investment.
- Applying too thick: More than 4 inches at once can smother existing grass and roots.
- Ignoring drainage: Even quality loam will not fix underlying drainage problems.
- Ordering too little: Running out mid-project means a second delivery fee and uneven results.
Frequently Asked Questions
A 2 cubic foot bag of loam covers about 2 square feet at 12 inches deep. For 1 cubic yard (27 cubic feet), you need about 14 bags. For smaller projects, calculate cubic feet needed and divide by 2.
Loam costs $15-$40 per cubic yard in 2026. Topsoil/loam mix runs $15-$25, screened loam costs $20-$30, garden soil blend is $30-$40, and premium black dirt reaches $35-$45 per cubic yard.
Loam weighs about 2,025-2,295 lbs per cubic yard depending on type. Screened loam weighs about 2,160 lbs (80 lbs per cubic foot), while garden soil blend weighs about 2,295 lbs (85 lbs per cubic foot).
Topsoil is the natural soil from the surface layer, while loam is a carefully blended mix of sand, silt, and clay. Loam provides better drainage, aeration, and nutrient retention than native topsoil alone.
For a new lawn, spread 4-6 inches of loam over the area. For overseeding existing lawns, 1-2 inches of top-dressing is sufficient. For garden beds, 8-12 inches of quality loam is recommended.
Yes, loam is excellent for raised beds. Garden soil blend or premium black dirt works best. Fill raised beds to within 1 inch of the top to allow room for watering. Most raised beds need 1-3 cubic yards of loam.