Steel plate weight calculator
1/4 inch A36 plate weighs 10.21 lb per square foot. A standard 4×8 sheet of 1/4 is 327 lb. 3/8 plate is 15.31 lb per square foot (490 lb for a 4×8). 1/2 inch is 20.42 lb per square foot (653 lb). Quick rule: multiply the thickness in inches by 40.84 to get lb/sq ft for any A36 plate. Enter your dimensions below for an exact weight.
Updated September 2026
Quick answer
1/4 inch A36 plate weighs 10.21 lb per square foot. Enter any plate dimensions below for an exact weight.
A36 steel plate weight by thickness
Formula: length × width × thickness × 0.2836 lb/in³. Numbers round to the nearest pound or kilogram. Real plate varies ±2–3% from these from mill tolerances. The sheet cost column stays blank until you type your supplier's price per pound.
Questions welders ask about this one
How much does 1/4 inch steel plate weigh per square foot?
10.21 lb per square foot. The formula is thickness in inches × 40.84. So 1/4 inch: 0.25 × 40.84 = 10.21 lb/sq ft. That 40.84 comes from 12 × 12 × 0.2836 (one square foot of steel, one inch thick). Works for any thickness of A36, 1018, or mild carbon steel. They are all the same density.
How do I figure the weight of a custom size plate?
Multiply length (inches) × width (inches) × thickness (inches) × 0.2836. Example: a 30 × 48 inch piece of 3/8 plate = 30 × 48 × 0.375 × 0.2836 = 153.1 lb. For odd shapes, calculate the bounding rectangle and subtract the cutout, or use the calculator above.
What does a full sheet of steel plate weigh?
Standard 4×8 foot sheet weights by thickness: 1/8 inch = 163 lb, 3/16 inch = 245 lb, 1/4 inch = 327 lb, 3/8 inch = 490 lb, 1/2 inch = 653 lb, 3/4 inch = 980 lb, 1 inch = 1,307 lb. All weights are A36 mild steel at 0.2836 lb/in³. Real plate varies ±2–3% from mill tolerances.
Weight is only half of material cost. To turn these pounds into a number you can quote, run the weld cost calculator for wire, gas, and labor per inch, or the job pricing calculator to build the whole bid.
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