How We Calculate

Area

Rectangle: length × width. Circle: 3.1416 × radius². Triangle: base × height ÷ 2. Odd shapes are split up and added together.

Volume

Area in square feet × depth in feet = cubic feet. Cubic feet ÷ 27 = cubic yards.

Weight

Cubic yards × the material's published weight per cubic yard ÷ 2,000 = short tons.

Bags

Volume ÷ the volume one bag holds (or yields, for concrete), rounded up to a whole bag.

Sod

Lawn area plus the extra you choose, ÷ the area one piece or pallet covers, rounded up.

Pavers

Area × pavers per square foot. The stone base and sand bed are worked out as volumes.

Board feet

Thickness (in) × width (in) × length (ft) ÷ 12, using the lumber trade's rules for nominal sizes.

Fence posts

Hole area minus the post's actual size, × the depth the concrete fills, ÷ the bag's yield.

We use the legal definitions published by the National Institute of Standards and Technology: 1 foot is exactly 0.3048 meters, 1 pound is exactly 0.453 592 37 kilograms, and a short ton is 2,000 pounds.

Nothing is rounded until the answer is shown on screen.

How much a cubic yard of stone weighs, how much a bag of concrete makes, how deep mulch should go: these come from transportation departments, university extension services, industry standards and the manufacturers' own data sheets. Each calculator names its source next to the number it backs.

When sources disagree, we show the range rather than pick one. When we can't find an authoritative source, we don't publish a figure.

Automated tests run every time the site changes. Some check our arithmetic against answers worked out by hand. Others check it against figures other people published:

• NIST: 1 cubic yard = 0.764 554 857 984 cubic meters, 1 acre = 43,560 square feet
• Purdue Extension: about 19 cubic yards of topsoil makes a 6-inch layer over 1,000 square feet
• Pavestone: 480 Holland pavers cover 103 square feet
• NHLA: a 1 × 12 × 12 inch board is one board foot
• Oregon State Extension: 25 one-cubic-foot bags of compost cover 100 square feet at 3 inches
• Black Kow: a 1 cubic foot bag covers 24 square feet at ½ inch
• Quikrete: every row of its bags-per-slab chart, at 4 and 6 inches
• Quikrete and Sakrete: every row of their bags-per-fence-post charts

If any check fails, the site doesn't update.

Bags, pieces and pallets are rounded up, because you can't buy part of one. Fence post bags follow the manufacturers' own rounding: up to the next bag unless the last one would cover 1.5% or less of the job.

Prices change by region and by week, so we never fill one in for you. Type the price from your supplier and the calculator does the rest.

• 7 CFR §1217.4 (softwood lumber board foot)

  nominal thickness of less than 1 inch is calculated as 1 inch

• American Concrete Institute, Concrete Terminology

  normalweight concrete: approximately 150 lb/ft3

• American Softwood Lumber Standard, PS 20-20 (NIST)

  §2.2: board feet use nominal thickness and width

• Black Kow Organic Cow Manure Blend (1 cu ft bag)

  1 cu ft; covers 24 sq ft at 1/2 inch

• Caltrans Maintenance Manual, Appendix (2014)

  p. Appen-31: broken stone 1 in. to dust, loose measure

• Coast of Maine Quoddy Blend Lobster Compost (1 and 2 cu ft bags)

• ICPI Tech Spec 2 (rev. Feb 2020)

  Patios: minimum 4 in. compacted base; residential driveways at least 6 in.

• Iowa DOT Materials IM 340

  Normal weight concrete is typically in the range of 140 - 150 lbs./cu. ft

• Kansas State University, MF2134 Raised Bed Gardening (2022)

  A 6- to 8-inch depth of the bed at minimum is recommended

• Mississippi State University Extension, P2951

  Pallet typically 450 to 500 sq ft; buy about 5 percent more

• Missouri DOT, Highway Maintenance Tables and Conversion Factors

  Loose weights: granite or limestone 2,410–2,590 lb/cu yd

• New Mexico State University, Guide H-509

  The absolute minimum soil depth for a lawn is 4 inches; 6 or more recommended

• NHLA Rules for the Measurement and Inspection of Hardwood (2023)

  ¶16: one board foot is 12 in. × 12 in. × 1 in.; under 1 in. measured as 1 in.

• NIST Handbook 44 (2024), Appendix C

• NRMCA, Concrete in Practice 8: Discrepancies in Yield

  Include an allowance of 4 to 10 percent over plan dimensions

• Oregon State University Extension, EM 9217 Interpreting Compost Analyses (2018)

  bulk density can range from 800 to more than 1,600 lb/cu yd; about 1,000 at 50% moisture

• Oregon State University Extension, EM 9308 How to Use Compost (2021)

  Lawn topdressing 1/4–1/2 in; new lawn 1–2 in; new beds 3–4 in; existing beds 1/4–1 in a year

• Pavestone Holland 60 mm spec sheet

  100 × 200 × 60 mm; 480 units per pallet; 103 sq ft per pallet

• Pavestone red volcanic rock bag label (0.5 cu ft, 19 lb)

  19 lb ÷ 0.5 cu ft × 27 = 1,026 lb/cu yd

• Pavestone river pebbles bag label (0.5 cu ft, 46 lb)

  46 lb ÷ 0.5 cu ft × 27 = 2,484 lb/cu yd

• Penn State Center for Dirt & Gravel Roads, DSA Tech Bulletin (2025)

  placed at an 8 in. depth and compacted to 6 in.

• Purdue Extension, AY-28-W

  Pallet about 450 sq ft; order about 10 percent more sod

• Quikrete All-Purpose Gravel (0.5 cu ft, 50 lb)

• Quikrete Concrete Mix 1101 data sheet (2022)

  40 lb yields about 0.30 cu ft; 50 lb 0.375; 60 lb 0.45; 80 lb 0.60; about 140 lb/cu ft

• Quikrete Fast-Setting Concrete Mix 1004 data sheet (2025)

  50 lb yields about 0.375 cu ft; hole about 3 times the post; depth 1/3 of overall post height

• Quikrete play sand (0.5 cu ft, 50 lb)

• Quikrete Product Guide (Fast-Setting Concrete bag chart)

  50 lb bags by slab area at 4 and 6 in; yields approximate, no waste

• Quikrete, Concrete Driveways and Curbs

  4 in. for passenger cars; 5 or 6 in. for trucks and heavy vehicles

• Quikrete, Concrete Patios

  Generally, a 4 in. thick slab

• Quikrete, Concrete Sidewalks and Small Slabs

  Sidewalks should be at least 4 in. in thickness

• Sakrete Fast Setting Concrete Mix data sheet

  50 lb yields 0.38 cu ft; post chart based on an average 10 in. hole; 4–6 in. gravel base

• Sakrete High-Strength Concrete Mix technical data sheet

  40 lb 0.30 cu ft; 60 lb 0.45; 80 lb 0.6

• Scotts Nature Scapes mulch (1.5 cu ft bag)

• Scotts Premium Topsoil (0.75 cu ft bag)

• UF/IFAS Florida-Friendly Landscaping

  Keep a 2- to 3-inch-deep layer of mulch on plant beds

• University of Illinois Extension (2018)

  applied at the recommended depth of two to three inches

• University of Minnesota Extension, Interpreting your compost report

  may range from 800 to 1500 pounds depending on the moisture content

• University of Wisconsin–Madison, Gravel PASER Manual (2015)

  For most conditions, a minimum gravel thickness of 6 in. is required

• US EPA, Volume-to-Weight Conversion Factors (2016)

  Wood chips: 243 lb/cu yd dry, 473 green

• USDA NRCS, Soil Quality Indicators: Bulk Density

• Vigoro and Scotts mulch, 2 cu ft bags (Home Depot listing)

• Vigoro pea gravel bag label (0.5 cu ft, 48 lb)

  48 lb ÷ 0.5 cu ft × 27 = 2,592 lb/cu yd

• Washington State University Extension, C075 Guide to Mulches

  Compost: Use 1 to 3 inches in vegetable gardens and flower, and shrub beds.

Tell us on the contact page. We check every report against the source and fix the calculator if it's wrong.