About Easy Garden Calc

Easy Garden Calc is a set of free calculators for yard and garden projects — mulch, soil, compost, potting mix, gravel, pavers, retaining walls, edging, landscape fabric, fence posts, seed, sod, fertilizer, lime, ponds and water. It exists to answer the question you have standing in the garden center or on the phone with a landscape yard: how many bags, yards or tons do I actually need?

Each calculator shows the formula it uses and the assumptions behind it. Where a number depends on the material or product — the density of a particular gravel, the seeding rate for a grass variety, the nitrogen in a fertilizer — it is an editable input with a typical default, and the page says so. Those defaults come from named, published sources — mostly university extension services (Penn State, the University of Minnesota, NC State, Clemson and others), the US Consumer Product Safety Commission for playground surfacing, industry installation specs (ICPI for pavers, Allan Block for walls), state water agencies for rainwater, and manufacturers’ product pages for bag yields and coverage — plus plain unit geometry. Where no public source gives a number (dump-truck payloads, how much topsoil settles), a supplier’s published guide is cited and the figure is shown as a typical range you can change. Each calculator lists the sources it relies on, and the full list is below. They are a starting point, not a substitute for the product label, your supplier’s figures, or your local extension office.

The site is free to use and is supported by advertising and by affiliate links to tools and supplies (as an Amazon Associate it earns from qualifying purchases). That doesn’t change the math. It is part of a small family of free project calculators that began with Easy Scale Calc (opens in a new tab). If you spot an error or want a calculator that isn’t here, use the contact page.

How we build and check the calculators

• Every calculator runs entirely in your browser — nothing you type is sent anywhere.
• Each page shows its formula, and every result shows the working with your own numbers, so you can check it by hand.
• Volumes use standard conversions (27 cubic feet in a cubic yard; 1,000 liters in a cubic meter). Bag and load counts are rounded up, and waste allowances are shown and editable.
• Application rates come from university extension services and product labels, and material weights are typical published densities, linked on each page. Your soil test and the label on your product always take priority.
• Every calculator is tested in both US and metric units, and every worked example is recomputed at build time so the numbers on the page always match the calculator.

How this content is made

The calculators, worked examples and guides on this site were drafted with the help of AI tools and then checked in several passes. Every number on a worked-example page is recomputed from the calculator at build time, so the text and the calculator can’t disagree. Formulas and published figures (building-code tables, manufacturer data sheets, extension-service rates) are checked against the linked sources, and structural tables are transcribed cell by cell and compared with the official text.

Automated checks run on every build: each calculator is tested in US and metric units and unit switching must round-trip exactly. If you find an error, tell us — corrections are fixed and logged below.

Sources we use

• Penn State Extension — Mulching Landscape Trees (opens in a new tab) — Mulch depth (2–4 in), trunk clearance, not stacking new mulch on old.
• University of Minnesota Extension — Mulching for soil and garden health (opens in a new tab) — Mulch depth range.
• Colorado State University Extension — Mulching (opens in a new tab) — Surface wood mulch and nitrogen; fabric under mulch; gravel vs wood heat.
• University of Missouri Extension — Fermented mulch can strike sour note with landscape plants (opens in a new tab) — Sour mulch.
• Clemson HGIC — Mulch (opens in a new tab) — Pine needle depth and slopes.
• NC State Extension — Pine Needle Mulch: the Myths and Legends (opens in a new tab) — Pine straw bale coverage; soil acidity myth.
• NC State Extension — Managing Longleaf Pine Straw (opens in a new tab) — Bale sizes vary.
• USDA Forest Service — Mulch flammability study (opens in a new tab) — Keep flammable mulches back from structures.
• University of Minnesota Extension — Raised bed gardens (opens in a new tab) — Raised bed soil mix.
• Penn State Extension — Soil health in raised beds (opens in a new tab) — Soil-to-compost ratio.
• Rutgers NJAES — FS1328 Soil for raised beds (opens in a new tab) — Settling of mineral vs organic fills.
• University of Missouri Extension — Raised-Bed Gardening (G6985) (opens in a new tab) — Bed widths and rooting depth.
• Oregon State University Extension — Raised bed gardening (FS 270) (opens in a new tab) — Bed construction.
• Washington State University — The myth of drainage material in container plantings (opens in a new tab) — Why gravel layers don’t improve drainage.
• Penn State Extension — Lawn Establishment (opens in a new tab) — Topsoil depth for new lawns.
• Penn State Extension — Using Composts to Improve Turf Performance (opens in a new tab) — Compost topdressing rates.
• Oregon State University Extension — How to use compost in gardens and landscapes (EM 9308) (opens in a new tab) — Compost application depths.
• University of Maryland Extension — Growing Vegetables in Containers and Salad Tables (opens in a new tab) — Container sizes and potting mix.
• University of Maryland Extension — Types of Containers for Growing Vegetables (opens in a new tab) — Container drainage and depth.
• NIST Handbook 44, Appendix C — General Tables of Units of Measurement (opens in a new tab) — Unit conversions (cubic yards, dry quarts).
• USDA-NRCS — Soil Bulk Density guide for educators (copy hosted by the Mississippi Soybean Promotion Board) (opens in a new tab) — Soil bulk density and pore space.
• FHWA — Gravel Roads Construction and Maintenance Guide (opens in a new tab) — Driveway crown; crushed vs rounded stone.
• FHWA — Open-graded aggregates report (AASHTO M43 / ASTM D448 designations) (opens in a new tab) — Stone size numbers such as No. 57.
• Quikrete — Concrete Mix (No. 1101) data sheet (opens in a new tab) — Bag yields; post hole sizing.
• Quikrete — Fast-Setting Concrete Mix (No. 1004) data sheet (opens in a new tab) — Fence post bag yields.
• U.S. CPSC — Public Playground Safety Handbook (opens in a new tab) — Loose-fill surfacing depths.
• U.S. CPSC — Outdoor Home Playground Safety Handbook (opens in a new tab) — Home play area surfacing depth and extent.
• ICPI Tech Spec 2 (copy hosted by ORCO) (opens in a new tab) — Paver bedding sand.
• Oregon State University Extension — 10-Step Guide to Installing Pavers (opens in a new tab) — Paver base, sand and slope.
• Belgard — Paver and wall installation guidelines (opens in a new tab) — Base and bedding depths.
• Belgard — Standard wall installation guide (opens in a new tab) — Retaining wall pad, burial and drainage.
• Allan Block — Basic installation (opens in a new tab) — Retaining wall trench and drainage.
• 2021 IRC R105.2 (Grant County, WA transcription) (opens in a new tab) — Retaining wall permit exemption up to 4 ft.
• University of Nevada, Reno Extension — Mulches for Nevada Landscapes (opens in a new tab) — Rock mulch and heat.
• UNH Extension — Should I use landscape fabric? (opens in a new tab) — Landscape fabric under mulch.
• EasyPro Pond Products — What to know about pond liners (opens in a new tab) — Pond liner sizing.
• Westlake Dimex — No-Dig Landscape Edging instructions (opens in a new tab) — Edging installation.
• Master Mark — How to install Dig-Free edging (opens in a new tab) — Edging stake spacing.
• Clemson HGIC — Designing for rain barrel success (opens in a new tab) — 0.623 gallons per sq ft per inch of rain; barrel safety.
• Clemson HGIC — Harvested rainwater on edibles (opens in a new tab) — Using rainwater on food crops.
• Colorado State University Extension — Rainwater collection in Colorado (opens in a new tab) — Colorado rain barrel limits.
• USGS Water Science School — Rain and precipitation (opens in a new tab) — Rainfall volume per acre.
• Penn State Extension — Turfgrass Seed and Seed Mixtures (opens in a new tab) — Seeding rates; pure live seed.
• NC State Extension Gardener Handbook — Lawns (opens in a new tab) — Warm-season seeding rates; nitrogen; watering.
• NC State Extension TurfFiles — Time for fall seeding of tall fescue (opens in a new tab) — Tall fescue rate and timing.
• Mississippi State University Extension — Sod Installation and Maintenance (opens in a new tab) — Sod pallet size and extra.
• Purdue Extension AY-28-W — Establishing a Lawn from Sod (opens in a new tab) — Sod pallets, extra and lime limits.
• University of Minnesota Extension — Fertilizing lawns (opens in a new tab) — N-P-K and nitrogen rates.
• University of Illinois Extension — Fertilizing your lawn (opens in a new tab) — Fertilizer rate math.
• Ohio State University Extension — Lime and the Home Lawn (opens in a new tab) — Lime per application and CCE.
• Penn State Extension — Liming Turfgrass Areas (opens in a new tab) — CCE and lime rates.
• Washington State University Extension C132 — Spacing of Landscape Plants (opens in a new tab) — Plant spacing.
• University of Illinois Extension — Ground Covers (opens in a new tab) — Groundcover spacing.
• UW-Extension (Taylor County) — Square Foot Gardening (opens in a new tab) — Plants per square.
• K-State Research and Extension (Johnson County) — How to Mulch Trees (opens in a new tab) — Mulch rings at least 3 ft out from the trunk; 6 ft is better.
• Messina’s — How much mulch fits in a truck bed? (opens in a new tab) — Pickup bed volumes for mulch.
• Harbor Soils — Cubic yard calculator and formula (opens in a new tab) — Topsoil and bark settle about 10% in the first season.
• Harbor Soils — How much topsoil do I need? (opens in a new tab) — New topsoil settles 10–15%; topdress ¼–½ in.
• NMSU Extension Guide H-509 — Turfgrass Establishment (opens in a new tab) — 4–6 in of topsoil after firming.
• Gravel Monkey — How many tons of gravel in a dump truck? (opens in a new tab) — Typical dump-truck payloads by axle count.
• ICPI/CMHA Guide Spec PAV-GSP-011-21 — Pavers on aggregate base (opens in a new tab) — Base extends past the edge restraint; 80 mm pavers for vehicles.
• ICPI Tech Spec 17 — Bedding sand selection (ORCO copy) (opens in a new tab) — Bedding sand 1–1½ in.
• Techniseal — RG+ polymeric sand (opens in a new tab) — Coverage per 50 lb bag for narrow joints.
• Alliance Gator — Supersand G2 (opens in a new tab) — Joint sand ⅛ in below the paver top; coverage per bag.
• Snap Edge — spike placement (opens in a new tab) — Edge restraint spikes about 12 in apart.
• Allan Block — Commercial installation manual and material estimation worksheet (ORCO copy) (opens in a new tab) — Wall burial, trench, drain pipe, adhesive and geogrid rules of thumb.
• Clemson HGIC — Overseeding with ryegrass (opens in a new tab) — Winter overseeding rates; which grasses not to overseed.
• UT Extension W161-J — Overseeding bermudagrass with perennial ryegrass (archived copy) (opens in a new tab) — Winter overseeding rates.
• University of Arizona AZ1683 — Overseeding (opens in a new tab) — Ryegrass 12–15 lb per 1,000 sq ft; don’t scalp.
• LSU AgCenter — Pure live seed calculation (opens in a new tab) — PLS = purity × germination.
• UConn Home & Garden — Understanding grass seed labels (opens in a new tab) — Seed coating on the label.
• NC State Extension — Tall fescue and Kentucky bluegrass lawn calendar (opens in a new tab) — New-lawn seeding rates.
• Rutgers NJAES FS584 — Seeding your lawn (opens in a new tab) — Seeding rates; weed-free straw mulch.
• UNH Extension — Starting and overseeding lawns (opens in a new tab) — Straw mulch on new seedings.
• UC IPM — Starter fertilizer (opens in a new tab) — Phosphorus at seeding.
• UMass — Fertilizer guide for lawns (opens in a new tab) — Starter fertilizer example.
• Sod Solutions — Square feet per pallet (opens in a new tab) — Pallet sizes and weights.
• Colorado State University Extension (CMG) — Sprinkler types (opens in a new tab) — Precipitation rates of spray heads and rotors.
• Hunter Industries — Standard MP Rotator (opens in a new tab) — About 0.4 in/hr.
• Texas Water Development Board — Texas Manual on Rainwater Harvesting (opens in a new tab) — First-flush volume.
• New Mexico OSE — Roof-Reliant Landscaping, Chapter 7 (opens in a new tab) — Roof runoff coefficients.
• Texas A&M AgriLife B-6240 — Rainwater harvesting: system planning (opens in a new tab) — Roof runoff coefficients.
• Minnesota Stormwater Manual — Green roofs (opens in a new tab) — Green roof runoff reduction.
• Webb’s Water Gardens — Pond pump sizing (opens in a new tab) — Waterfall flow per foot of spill width.
• smartpond — Planning a waterfall (opens in a new tab) — Waterfall flow per inch of width.
• Ohio State University Extension — AGF-505, Soil pH and lime (opens in a new tab) — SMP buffer pH lime equations.
• NDSU Extension H1824 — Managing turfgrass from a soil test (opens in a new tab) — Sulfur rates to lower pH; per-application cap on turf.
• Clemson HGIC — Changing the pH of your soil (opens in a new tab) — Sulfur and soil texture.
• Purdue Extension AY-22 — Fertilizing established cool-season lawns (opens in a new tab) — Nitrogen per application; slow-release limits.
• Connecticut OLR report 2012-R-0076 — State lawn fertilizer phosphorus laws (opens in a new tab) — States restricting phosphorus on lawns.
• University of Minnesota Extension — How to calculate herbicide rates (opens in a new tab) — Product from active-ingredient rates.
• University of Minnesota Extension — Crabgrass (opens in a new tab) — Pre-emergent timing.
• US EPA — Introduction to pesticide labels (opens in a new tab) — The label is the law.
• Wisconsin DOT research report 0092-22-05 — Weight-volume relationships and conversion factors for soils and aggregates (opens in a new tab) — Compacted dense-graded base about 1.75–2.1 tons per cubic yard; soil swell from bank to loose.
• FHWA-HRT-15-034 — Strength characterization of open-graded aggregates (opens in a new tab) — No. 57 stone loose and maximum unit weights.
• Smith Bros. Mulch — #411 limestone (opens in a new tab) — #411: #57-size stone with screenings.
• MRLM Landscape Materials — #411 limestone (opens in a new tab) — #411 as a driveway topping.
• WSU Extension (Clark County) — Improving drainage (opens in a new tab) — French drain construction and slope.
• Penn State Center for Dirt and Gravel Road Studies — Underdrains (opens in a new tab) — Pipe size, clean stone, geotextile, 1% slope.
• Acme Sand & Gravel — Flagstone thickness, coverage and delivery (opens in a new tab) — Flagstone coverage per ton by thickness.
• Earthstone — Material coverage (opens in a new tab) — Flagstone coverage per ton.
• 811 — Before You Dig (opens in a new tab) — Utility locates before digging post holes.

How the site is funded

Easy Garden Calc is free and has no sign-up. It is supported by display advertising and by affiliate links — when you buy something through a product link we may earn a small commission at no extra cost to you. Recommendations are chosen for fit with the job, not commission.

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