Steel Plate Weight Calculator — ft, lbs
How to use this calculator
Pick a plate shape, enter dimensions in feet and inches (fraction selectors give 1/8″ precision), choose the alloy, and set thickness and quantity. Carbon steel weighs 40.8 lb/ft² per inch of thickness (490 lb/ft³ × t). Use it to price laser/plasma-cut blanks, base plates, gussets and shim stock before ordering.
Materials — Carbon steel A36 (490 lb/ft³), Stainless 304/316 (501 lb/ft³), Aluminum 6061 (169 lb/ft³), Copper (559 lb/ft³).
Cost — enter price per pound (mill basis) or a flat price per finished plate to estimate the order total.
Saved Calculations
| Time | Shape | Material | Area ft² | Wt/plate | Total lbs | Cost |
|---|
How to Calculate Steel Plate Weight
Weight comes straight from density: a 1″-thick carbon-steel plate weighs 40.8 lb per square foot (490 lb/ft³ ÷ 12). Multiply by area and thickness to size a base plate, gusset, bearing plate or stiffener, then add a 5–10% allowance for cut kerf and edge prep waste when buying raw stock. For connection design pair this with the bolt pattern calculator and confirm member sizes with the steel beam weight calculator or steel column calculator.
How to use it
Select rectangle, circle, triangle or ring, enter the governing dimensions, set thickness from common stock gauges (¼″ to 1″+), and choose the alloy. Weight per plate and total weight (lbs and tons) update on every input change; toggle Cost to price by the pound or by the finished plate.
Material densities
Carbon steel A36: 490 lb/ft³. Stainless 304/316: 501 lb/ft³. Aluminum 6061: 169 lb/ft³. Copper: 559 lb/ft³. Values follow ASTM A6 / AISC 360 handbook references.
Formulas
Rectangle A = L × W. Circle A = π × (D/2)². Triangle A = ½ × B × H. Ring A = π × ((D₀/2)² − (Dᵢ/2)²). Volume = A × thickness (consistent feet). Weight = Volume × density; total = weight × quantity.
FAQ
Why is my plate heavier than the steel table? Mill plate is supplied to ASTM A6 thickness tolerance and can run slightly over nominal; treat the result as a minimum ordering weight. Does this include holes or copes? No — it is the gross blank weight; deduct large openings separately. Working in metric? Use the metric plate weight calculator. For embedded plates in concrete see the concrete beam calculator and rebar calculator.
Ordering tips
Mill-direct A36 in 2025 runs about $0.70–1.10/lb for ¼″–1″ carbon plate, $2.50–4.50/lb for 304/316 stainless, and $3–5/lb for 6061 aluminum — service-center cut-to-size pricing is 30–60% higher. The biggest takeoff mistake is ordering by net blank area without adding 5–10% for kerf, plasma bevel, and offcut drop, and forgetting that A36 plate is sold in standard sheets (4×8, 4×10, 5×10, 6×20 ft) so a 4.5×8 ft part forces a 5×10 ft purchase. Anything thicker than 1¼″ is normally A572 Gr 50; over 8″ thick is hot-rolled to ASTM A6 tolerances and may need stress relief per AWS D1.1. Cross-check connection design with the bolt pattern calculator and members with the steel beam weight calculator.
