Calculate how much topsoil, compost or bed mix a lawn or garden bed needs — in cubic yards, which is how soil is quoted and delivered.
A new lawn measuring 60 by 35 feet, finished at 4 inches. Area is 60 x 35 = 2,100 square feet. Cubic yards are 2,100 x 4 / 324 = 25.93. Add the 10 percent consolidation allowance: 25.93 x 1.10 = 28.5, so order 29 cubic yards. Check it against Penn State's own rate, 3.1 cubic yards per 1,000 square feet per inch: 2.1 x 3.1 x 4 = 26.0 cubic yards before allowance, which agrees. For weight, screened sandy loam at 2,392 lb per cubic yard gives 29 x 2,392 = 69,368 lb, or 34.7 US short tons at 2,000 lb to the ton. That is an as-delivered weight; it includes whatever water the pile was holding when it was loaded.
One cubic yard spread 1 inch deep covers 324 square feet, because 27 cubic feet each cover 12 square feet at that thickness. So cubic yards equals area in square feet times depth in inches, divided by 324. At 2 inches a yard covers 162 square feet, at 4 inches 81, at 6 inches 54. Treat the depth you enter as the settled depth you want to end up with, then add the allowance. For weight, take the pounds per cubic yard straight from the table rather than converting twice.
The calculator uses a density range per material, not a single number, because real aggregate varies with moisture, grading and how hard it has been compacted. Where a figure could not be traced to a published document it is labelled as an estimate.
| Material | Density used | Source |
|---|---|---|
| Screened topsoil, loose (sandy loam) EPA lists soil/sandy loam, loose at 2,392 lb per cubic yard, which is 88.6 lb per cubic foot. It is a single point rather than a range, and it is an as-delivered weight: the water in the pile is counted. A wet load weighs more than this, a dried one less. |
88.6 lb/cu ft | US EPA, Standard Volume-to-Weight Conversion Factors, updated 2/28/2006, Construction & Demolition Debris table, entry "Soil/sandy loam, loose" |
| Compost, as-is bulk density Oregon State gives an as-is bulk density of 800 to more than 1,600 lb per cubic yard, about 30 to 59 lb per cubic foot. The spread comes from three things together - moisture content, particle size and compaction - so no single figure substitutes for weighing what you were sent. |
30–59 lb/cu ft | Oregon State University Extension Service, EM 9217, Interpreting Compost Analyses, October 2018 |
| Topsoil and compost blend for beds (estimate) The author's estimate, not a published density. Half topsoil and half light compost gives (88.6 + 30) / 2 = 59; two parts topsoil to one part mid-range compost gives (2 x 88.6 + 44.5) / 3 = 74. Your supplier's actual blend ratio beats both numbers. |
59–74 lb/cu ft estimate |
Not sourced. Arithmetic on the EPA and Oregon State figures above. |
| Medium-textured soil in place, dry (reference, not an order option) NRCS gives 1.33 g/cm3, or 83 lb per cubic foot, for a medium-textured soil at roughly 50 percent pore space. This is a dry bulk density - dry soil weight divided by volume, water excluded - so it is not comparable with the as-delivered weight a supplier invoices. |
83 lb/cu ft | USDA NRCS, Soil Quality Indicators: Bulk Density, June 2008 |
| Compacted silty soil, root-restricting (reference, not an order option) The same NRCS sheet puts the density at which roots stop growing in a silty soil above 1.65 g/cm3, about 103 lb per cubic foot. Also a dry weight. It sits here as a threshold to stay under, not a product to order: reaching it is the failure you are avoiding. |
103 lb/cu ft | USDA NRCS, Soil Quality Indicators: Bulk Density, June 2008 |
These are the figures this calculator uses. Each names the document it came from, so you can open it and check. Where a figure is an estimate rather than a published number, it says so. Two of the densities below are reference thresholds for judging soil you already have, not materials you can order, and the table says which.
| Item | Figure | Source |
|---|---|---|
| Screened topsoil, loose sandy loam, as delivered | 2,392 lb per cubic yard = 88.6 lb/cu ft (1.20 US short tons) | US EPA, Standard Volume-to-Weight Conversion Factors, updated 2/28/2006, C&D Debris table, "Soil/sandy loam, loose". Includes water. |
| Compost, as-is bulk density | 800 to more than 1,600 lb per cubic yard = about 30-59 lb/cu ft | Oregon State University Extension Service, EM 9217, Interpreting Compost Analyses, Oct 2018. Range attributed to moisture content, particle size and compaction. |
| Medium-textured soil at about 50% pore space, in place | 1.33 g/cm3 = 83 lb/cu ft | USDA NRCS, Soil Quality Indicators: Bulk Density, June 2008. A dry bulk density: dry soil weight over volume, water excluded. |
| Bulk density that restricts root growth, silty soil | greater than 1.65 g/cm3 = about 103 lb/cu ft | Same NRCS sheet, June 2008. Also a dry weight. |
| Coverage of one cubic yard at 1 inch deep | 324 square feet (27 x 12) | Arithmetic. Corroborated by Penn State Extension, Using Composts to Improve Turf Performance, updated 1 Jan 1997 (Landschoot): a 1-inch layer is about 3.1 cu yd per 1,000 sq ft; 1,000/324 = 3.09. |
| Topsoil depth for establishing turf | minimum 4 to 6 inches, firmed or settled depth | Penn State Extension, Lawn Establishment, updated 19 Sep 2025. Same page: work 2 inches into the upper 2-3 inches of subsoil. |
| Compost top-dressing on an established lawn | 1/4 to 1/2 inch per pass | Oregon State Extension EM 9308, Feb 2021, reviewed 2025, Lawns. Clemson HGIC 1227, rev. 30 Sep 2020, caps one application at 1/2 inch. |
| Settlement of regraded construction soil | up to 2 inches per foot of soil moved (about 17%) | Purdue University Turfgrass Science, Zac Reicher, Seeding Lawns Around New Construction, 8 Apr 2004. A ceiling, and not a figure for a spread topsoil layer. |
Every figure names the document it came from. Densities: EPA's volume-to-weight table (2/28/2006), Oregon State EM 9217 (Oct 2018), USDA NRCS Soil Quality Indicators: Bulk Density (June 2008). Depths: Penn State Extension Lawn Establishment (updated 19 Sep 2025) and Using Composts to Improve Turf Performance, updated 1 Jan 1997 (Landschoot), Oregon State EM 9308 (Feb 2021, reviewed 2025), Clemson HGIC 1227 (rev. 30 Sep 2020), Purdue HO-200-W (rev. 4/02). Settlement: Purdue Turfgrass Science, 8 Apr 2004. Only the blend density is unsourced, and it says so.
Start with coverage, not volume. One cubic yard spread one inch deep covers 324 square feet, because a cubic yard holds 27 cubic feet and each of those covers 12 square feet at an inch. Multiply your area in square feet by the depth in inches and divide by 324. Penn State Extension's Lawn Establishment page, updated 19 September 2025, puts the requirement for turf at "a minimum of 4 to 6 inches (firmed or settled depth) of a good-quality topsoil", and that parenthesis is the whole trick: it describes the depth you finish at, not the depth you spread. Penn State's turf compost sheet reaches the same coverage arithmetic from the other end, pricing a one-inch layer at about 3.1 cubic yards per 1,000 square feet. One thousand divided by 324 is 3.09, so the two agree.
Depth depends on the job. For new turf Penn State asks for 4 to 6 inches settled, and adds that ideally 2 inches of it are worked into the upper 2 to 3 inches of subsoil so roots and water do not stall at an abrupt seam. An established lawn takes far less. Oregon State Extension's EM 9308, February 2021, reviewed 2025, spreads compost a quarter to half an inch deep across turf; Clemson's HGIC 1227, revised 30 September 2020, caps one pass at half an inch because a thicker blanket shades and stunts the grass. EM 9308 puts 3 to 4 inches of compost on a new garden bed and incorporates it into the top 8 to 12 inches. For raised beds, Purdue's HO-200-W, revised 4/02, says a bed under 6 inches tall needs no side support, and one over 18 inches on a poorly drained site may want drainage material underneath.
Here compaction is the failure mode, not the target. USDA NRCS's Soil Quality Indicators: Bulk Density sheet, June 2008, puts a medium-textured soil at roughly 50 percent pore space at 1.33 g/cm3, or 83 lb per cubic foot, and puts the density at which roots stop growing in a silty soil above 1.65 g/cm3, about 103 lb per cubic foot. A gravel base is rolled deliberately to hit a density specification; topsoil that arrives at 1.65 has simply failed. The two NRCS figures sit on different texture bases, so treat them as two thresholds rather than subtracting one from the other. So keep loaded machines and stockpiles off ground you have just spread, and do not work soil wet. One caution on that number: NRCS defines bulk density as dry soil weight over volume, water excluded, whereas the 2,392 lb per cubic yard you are invoiced for is an as-delivered weight with the water still in it.
324 square feet at 1 inch deep, since a cubic yard is 27 cubic feet and each covers 12 square feet at that thickness. It halves as the depth doubles: 162 square feet at 2 inches, 108 at 3, 81 at 4, 54 at 6. Penn State's turf compost sheet agrees, rating a one-inch layer at about 3.1 cubic yards per 1,000 square feet.
Penn State Extension's Lawn Establishment page, updated 19 September 2025, says a minimum of 4 to 6 inches, firmed or settled depth, of good-quality topsoil is typically needed for good-quality turf. It also suggests working 2 of those inches into the upper 2 to 3 inches of subsoil, which eases the transition and improves drainage at the interface.
EPA's conversion table gives loose sandy loam at 2,392 lb per cubic yard, about 1.20 US short tons. That is an as-delivered weight and includes the water in the pile. NRCS's 1.33 g/cm3, or 83 lb per cubic foot, is a different quantity - a dry bulk density, water excluded. Do not compare the two directly.
Yes, though the allowance is a judgement call. Purdue Turfgrass Science writes that each foot of soil moved could settle up to two inches, roughly 17 percent - stated as a ceiling, and about regraded construction soil rather than a spread topsoil layer. No published shrinkage factor for spread topsoil turned up, so this calculator adds 10 percent and says plainly what that is.
Purdue's HO-200-W, Container and Raised Bed Gardening, revised 4/02, notes that most vegetables and flowers root 2 to 3 feet deep in good soil. Beds under 6 inches tall need no side support; beds over 18 inches on poorly drained sites may need drainage material underneath.
A quarter to half an inch per pass. Oregon State's EM 9308 gives that band, Clemson's HGIC 1227 caps a single application at half an inch, and Penn State's turf compost article says apply about a quarter inch and work it in. At a quarter inch, 1,000 square feet takes 1,000 x 0.25 / 324 = 0.77 cubic yards.