Loam Calculator — Estimate Topsoil & Loam Volume Instantly

Calculate exactly how much loam or topsoil your landscaping project needs. Free online loam calculator with cubic yard, cubic foot, and bag count estimates plus step-by-step breakdown.

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Loam Calculator

Enter your project dimensions to calculate the total loam volume needed in cubic yards, cubic feet, and estimated bag count.

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Enter dimensions and click Calculate Loam Volume to see the result.

Loam Volume Formula Explained

The loam volume formula calculates the total amount of soil needed by multiplying the surface area by the desired depth. All measurements must be in consistent units before calculating.

Volume (cu ft) = Length (ft) × Width (ft) × Depth (ft)
Volume (cu yd) = Volume (cu ft) ÷ 27
Bags Needed ≈ Volume (cu ft) ÷ Bag Size (cu ft)

Variable Definitions

  • Length & Width — The dimensions of the area to be covered, measured in feet (imperial) or meters (metric)
  • Depth — How thick the loam layer should be, typically measured in inches (imperial) or centimeters (metric)
  • Cubic Yard (cu yd) — A volume unit equal to 27 cubic feet, the standard unit for bulk soil delivery
  • Bag Size — Common loam bags hold 1, 1.5, or 2 cubic feet of material

How to Calculate Loam Volume for Landscaping

Determining the right amount of loam prevents over-ordering and under-ordering. Follow these steps for an accurate loam estimate:

  1. Measure the area — Record the length and width of your garden bed, lawn, or landscaping project in feet or meters.
  2. Choose your depth — Decide how deep the loam should be. Garden beds typically need 4–6 inches; new lawns need 4–8 inches; top dressing needs 1–2 inches.
  3. Convert depth to feet — If using inches, divide by 12. For example, 6 inches = 0.5 feet. For metric, convert centimeters to meters by dividing by 100.
  4. Calculate cubic feet — Multiply length × width × depth (all in feet) to get the volume in cubic feet.
  5. Convert to cubic yards — Divide the cubic feet result by 27 to get cubic yards, the standard bulk ordering unit.
  6. Estimate bag count — Divide cubic feet by the bag size (1, 1.5, or 2 cu ft) to determine how many bags to purchase.

For a 20 ft × 10 ft garden with 6 inches of loam: 20 × 10 × 0.5 = 100 cubic feet, or about 3.7 cubic yards.

Loam Calculator Examples

Example 1: Small Garden Bed

A 12 ft × 8 ft raised bed with 4 inches of loam.

Depth in feet = 4 ÷ 12 = 0.333 ft
Volume = 12 × 8 × 0.333 = 32 cu ft
Cubic Yards = 32 ÷ 27 ≈ 1.19 cu yd
Bags (1 cu ft each) ≈ 32 bags

Example 2: New Lawn Installation

A 40 ft × 25 ft lawn area with 6 inches of loam.

Depth in feet = 6 ÷ 12 = 0.5 ft
Volume = 40 × 25 × 0.5 = 500 cu ft
Cubic Yards = 500 ÷ 27 ≈ 18.5 cu yd
Bags (2 cu ft each) ≈ 250 bags

Example 3: Metric Calculation

A 5 m × 3 m plot with 15 cm of loam.

Depth in meters = 15 ÷ 100 = 0.15 m
Volume = 5 × 3 × 0.15 = 2.25 m³
Cubic Yards ≈ 2.94 cu yd
Bags (1 cu ft each) ≈ 80 bags

Real-World Loam Applications

  • Garden Bed Preparation: Calculate the exact loam volume needed to fill raised beds or amend existing garden soil for optimal plant growth.
  • New Lawn Installation: Determine how much screened loam to spread before seeding or laying sod for a healthy, level lawn.
  • Top Dressing: Estimate the thin layer of loam needed to overseed and rejuvenate an existing lawn without smothering the grass.
  • Landscaping Berms: Calculate soil volume for creating raised landscape features, mounds, and berms for visual interest and drainage.
  • Planter Boxes: Determine loam requirements for large commercial planters, tree boxes, and streetscape containers.
  • Erosion Repair: Estimate fill material needed to restore eroded areas on slopes, embankments, and drainage swales.

People Also Ask About Loam Calculation

Multiply the length by the width of your area to get square footage, then multiply by the desired depth (converted to feet). This gives cubic feet. Divide by 27 to get cubic yards. For example, a 10ft × 20ft garden with 6 inches of loam needs 100 cubic feet or about 3.7 cubic yards.
One cubic yard equals 27 cubic feet. With standard 1-cubic-foot bags, you need 27 bags per cubic yard. For 1.5-cubic-foot bags, you need 18 bags. For 2-cubic-foot bags, about 14 bags. For projects over 1 cubic yard, bulk delivery is typically more cost-effective than bagged loam.
For new lawns, apply 4 to 6 inches of loam over the prepared subgrade. This depth supports healthy root development. For overseeding or top dressing an existing lawn, apply a thinner 1 to 2-inch layer of screened loam to avoid smothering existing grass.
Topsoil is the uppermost soil layer containing organic matter and microorganisms. Loam refers to the ideal soil texture—roughly 40% sand, 40% silt, and 20% clay. High-quality topsoil is often loamy, but not all topsoil qualifies as true loam. Screened loam is processed to remove debris.
A cubic yard of dry loam typically weighs between 2,000 and 2,400 pounds (1–1.2 tons). Moist loam can weigh up to 2,700 pounds per cubic yard. This is important for determining delivery vehicle capacity and whether you need equipment to move the material.

Loam Calculator Frequently Asked Questions

Yes. Toggle between imperial (feet/inches) and metric (meters/centimeters) using the unit buttons above the input fields. The calculator automatically converts and displays results in the appropriate volume units including cubic meters and cubic yards.
For projects requiring more than 1 cubic yard (27 cubic feet), bulk delivery is usually more economical. Bagged loam is convenient for small projects, patching, and when access prevents bulk dumping. Use this calculator to determine your total volume, then compare bulk vs. bagged pricing.
Absolutely. The volume formula works for any bulk material including topsoil, compost, mulch, sand, gravel, and fill dirt. Just input your dimensions and the calculator provides accurate volume estimates regardless of material type. Check our related landscaping calculators for material-specific tools.
Loam settles and compacts over time. It's wise to add 10–15% extra volume to account for compaction, especially for deeper applications. For example, if your calculation shows 3 cubic yards, consider ordering 3.5 cubic yards to ensure you have enough after settling.
Screened loam has been passed through a mesh screen (typically ½-inch or ¾-inch) to remove rocks, roots, and debris. It's ideal for lawns and garden beds. Unscreened loam is less processed and may contain stones; it's suitable for fill applications where a fine texture isn't required.
The bag count is a mathematical estimate based on the labeled bag volume. Actual coverage may vary slightly due to bag settling, compaction during spreading, and moisture content. Always round up and consider buying 5–10% extra bags to account for these variables.

Loam & Soil Volume Glossary

Loam

A balanced soil mixture of approximately 40% sand, 40% silt, and 20% clay, prized for its fertility, drainage, and workability in landscaping.

Cubic Yard

A volume unit equal to 27 cubic feet (3 ft × 3 ft × 3 ft). The standard measurement for bulk soil, mulch, and aggregate orders.

Screened Loam

Loam that has been processed through a mesh screen to remove rocks, roots, and debris. Preferred for lawns, garden beds, and finish grading.

Topsoil

The uppermost 2–8 inches of natural soil, rich in organic matter. High-quality topsoil is often loamy in texture.

Compaction

The settling and densification of soil over time due to gravity, water, and foot traffic. Plan for 10–15% extra volume to compensate.

Top Dressing

A thin layer (1–2 inches) of loam or compost spread over an existing lawn to improve soil quality without killing the grass.

Fill Dirt

Subsoil material used for raising grade, filling holes, and creating base layers. Contains minimal organic matter and is not suitable for planting.

Soil Amendment

Materials like compost, peat moss, or sand mixed into existing soil to improve its structure, drainage, or nutrient content.

Editorial Review & Methodology

This loam calculator was built and reviewed by the NumbrWiz Editorial Team. The loam volume formula is a standard geometric volume calculation used throughout the landscaping and construction industries, verified against industry-standard references including landscape architecture guidelines and bulk material supplier practices.

  • Formula verification: Cross-checked against standard cubic volume formulas and bulk material ordering guides used by landscaping professionals.
  • Edge case testing: Tested with zero-depth scenarios, extremely large areas, fractional measurements, and unit conversion accuracy.
  • UX review: Designed for intuitive input with clear error messaging, unit toggling, and comprehensive step-by-step breakdown.

Transparency note: All calculations run client-side in your browser. No data is ever collected, stored, or transmitted. Results are for planning and estimation purposes; always confirm quantities with your supplier before ordering. Consider adding 10–15% extra for compaction and settling.

Page last reviewed: May 2026 · NumbrWiz Editorial Team