Every constant used in our calculators is drawn from published manufacturer specs, industry standards, or exact mathematical identities. This page lists each value and its source so you can verify our calculations independently.
Universal Conversions
| Conversion | Value | Source |
|---|
| 1 cubic yard → cubic feet | 27 | Exact mathematical identity |
| 1 ton (US short) → pounds | 2,000 | US customary standard |
| 1 square yard → square feet | 9 | Exact mathematical identity |
Mulch
| Constant | Value | Source |
|---|
| Bag yield | 2 cu ft per bag | Industry standard bag size (Scotts, Vigoro, etc.) |
| Bags per cubic yard | 13.5 | 27 ÷ 2 = 13.5 (exact) |
| Default depth | 3 inches | University extension service best practice for landscape beds |
| Default waste factor | 5% | Industry rule of thumb for regular-shaped beds |
Gravel / Crushed Stone
| Material | Tons/cu yd | Source |
|---|
| Pea gravel | 1.40 | Aggregate industry standard (supplier averages) |
| Crushed stone (3/4") | 1.40 | Aggregate industry standard |
| Crushed limestone | 1.50 | Aggregate industry standard |
| River rock (1–3") | 1.35 | Aggregate industry standard |
| Decomposed granite | 1.35 | Aggregate industry standard |
Topsoil
| Constant | Value | Source |
|---|
| Density | 1.10 tons/cu yd | Soil supplier industry standard (dry topsoil) |
| 40 lb bag yield | 0.75 cu ft | Manufacturer average (Scotts, Miracle-Gro) |
Sand
| Material | Tons/cu yd | Source |
|---|
| All-purpose / paver sand | 1.35 | Supplier standard |
| Play sand / mason sand | 1.30 | Supplier standard |
| 50 lb bag yield | 0.50 cu ft | Manufacturer average |
Sod
| Constant | Value | Source |
|---|
| Piece size | 16" × 24" = 2.67 sq ft | US sod industry standard piece |
| Pallet coverage | ~450 sq ft (170 pieces) | US sod farm industry standard |
Concrete (bagged pre-mix)
| Bag size | Yield (cu ft) | Source |
|---|
| 40 lb | 0.30 | Quikrete published product specifications |
| 50 lb | 0.375 | Quikrete published product specifications |
| 60 lb | 0.45 | Quikrete / Sakrete published specifications |
| 80 lb | 0.60 | Quikrete / Sakrete published specifications |
Paint
| Surface type | Coverage (sq ft/gallon) | Source |
|---|
| Standard wall paint | 350 | Sherwin-Williams / Benjamin Moore average |
| Premium paint | 400 | High-coverage product average |
| Primer | 250 | Primer manufacturer average |
| Textured surface | 275 | Industry rule for textured/popcorn surfaces |
Flooring, Tile & Drywall
| Constant | Value | Source |
|---|
| Flooring waste (straight) | 10% | NWFA installation guidelines |
| Flooring waste (diagonal) | 15% | NWFA installation guidelines |
| Tile waste (straight) | 10% | TCNA Handbook for Ceramic, Glass and Stone Tile Installation |
| Tile waste (diagonal) | 15% | TCNA Handbook |
| Thinset (50 lb bag) | 40 sq ft | 3/8" notched trowel, manufacturer average |
| Drywall sheet (4×8) | 32 sq ft | Exact: 4 × 8 = 32 |
| Joint compound (1 gal) | 100 sq ft | USG / National Gypsum average for 3-coat finish |
Grass Seed
| Grass type | New lawn (lbs/1k sq ft) | Source |
|---|
| Tall Fescue | 7 | University extension service seeding guides |
| Kentucky Bluegrass | 2.5 | University extension service seeding guides |
| Perennial Ryegrass | 7 | University extension service seeding guides |
| Bermudagrass | 1.5 | University extension service seeding guides |
Lumber
| Constant | Value | Source |
|---|
| Board feet formula | (T" × W" × L ft) ÷ 12 | Standard lumber industry definition |
| 2×4 actual size | 1.5" × 3.5" | NHLA / lumber industry standard |
| 2×6 actual size | 1.5" × 5.5" | NHLA / lumber industry standard |
| Default waste | 10% | Contractor standard overage |
Insulation
| Type | R-value/inch | Source |
|---|
| Fiberglass batts | R-3.2 | DOE / manufacturer specs |
| Mineral wool (Rockwool) | R-3.8 | DOE / manufacturer specs |
| Blown-in fiberglass | R-2.7 | DOE / manufacturer specs |
| Blown-in cellulose | R-3.6 | DOE / manufacturer specs |
| Closed-cell spray foam | R-6.5 | ASHRAE standards |
Pavers
| Constant | Value | Source |
|---|
| Default waste | 10% | Contractor standard |
| Sand bedding depth | 1 inch | ICPI (Interlocking Concrete Pavement Institute) standard |
| Gravel base depth | 4 inches | ICPI standard for residential patio |
Fence
| Constant | Value | Source |
|---|
| Post spacing | 8 ft on-center | Standard residential fence industry practice |
| Concrete per post | 2 bags (50 lb) | Standard for 4×4 post in 10–12" hole |
| Picket formula | Linear ft × 1.6 × 1.05 | Mathematical + 5% waste |
Deck
| Constant | Value | Source |
|---|
| Joist spacing | 16 in OC | IRC (International Residential Code) |
| Beam spacing | 8 ft OC | Standard residential deck framing |
| Decking waste | 10% | NWFA / contractor standard |
Asphalt
| Constant | Value | Source |
|---|
| Hot mix density | 145 lbs/cu ft = 1.96 tons/cu yd | Asphalt paving industry standard |
| Default waste | 5% | Contractor standard overage |
Note: All density and yield values are approximate averages. Actual weights vary with moisture content, compaction, and product. We recommend confirming quantities with your local supplier before placing a large order. See our Calculation Assumptions page for default values and rounding rules.