Precision estimating instrument
Steel Plate Weight Calculator
Get Exact Plate Weight in Seconds, for Free
Enter length, width and thickness and read the exact mass of any plate, disc, ring or triangular blank. Thirty-plus alloy densities, five unit systems and a live cutting diagram that redraws as you type - so the number on your quote matches the metal on your truck.
- 4 Blank geometries
- 30+ Alloy densities
- 5 Unit systems
- 100% free
No sign-up · nothing you enter is uploaded · runs entirely in your browser
Plate weight calculator
Dimensions
The diagram and the result update on every keystroke.
Enter the area straight from your nesting or CAD output — no length and width needed.
Quick presets
Result updates as you type
Final result
LiveTotal weight
1 pcs157 kg
Live blank diagram
Focus any dimension field to highlight it on the drawing.
- Weight per piece
- 157 kg
- Volume per piece
- 20,000 cm³
- Face area per piece
- 2 m²
- Estimated material cost
- —
Enter a price per kg to cost this lot.
Formula applied
m = 200 × 100 × 1 cm³ × 7.85 g/cm³
Total weight
157 kg
Definition
What Is A Steel Plate Weight
Steel plate weight is the mass of a flat steel product, found by multiplying its volume by the density of its grade. A 2000 × 1000 × 10 mm mild steel plate weighs 157 kg (346.1 lb). The same plate cut from aluminium 6061 weighs 54 kg (119 lb), because density, not size, carries the difference. Steel plate is flat-rolled steel over 6 mm (0.2362 in) thick, and anything thinner is classed as sheet.
Steel is an alloy of iron and carbon, and carbon is what makes it resist breaking. Chromium, nickel and manganese change ductility, hardness, durability and corrosion resistance, and shift density along with them: stainless 316 reaches 7,980 kg/m³ against 7,850 kg/m³ for plain carbon steel. Those alloying elements are why a grade is chosen before a weight is trusted.
Weight then decides 3 things. Mills and stockholders price steel per unit weight, so weight is the invoice. Hauliers charge by load, so weight sets the lorry count. Cranes and slings are rated by load, so weight decides whether a finished assembly lifts at all, and that applies wherever plate carries load, from gusset plates in trusses and flanges with fin support for posts to the pressure vessels behind boats, ships and military vehicles.
The three measurements
- Volume
- 0.02 m³
- Mass in mild steel
- 157 kg
20,000 cm³ · 1,220 in³
346.1 lb · 0.157 t
Three steps
How To Calculate Steel Plate Weight?
To calculate steel plate weight, multiply length by width by thickness for the volume, then multiply that volume by the density of the grade. The calculator above runs all three steps as you type, and the drawing redraws so you can confirm the geometry before trusting the number.
- 01
Step 1: Enter Length, Width & Thickness
Type the length, width and thickness into the calculator above. Each field carries its own unit, so a drawing dimensioned in metres for length and millimetres for thickness goes in exactly as drawn. Switch the geometry to a disc, ring or triangle and the fields change with it.
- mm
- cm
- m
- in
- ft
- 02
Step 2: Choose Your Steel Grade
Pick the grade from the material list. The grade sets the density that the formula runs on, and 37 densities ship with the calculator across carbon steel, stainless, non-ferrous metals and engineering plastics. Grades outside the list go in as a custom density.
Density by grade
- Carbon steel
- 7,840 kg/m³
- C1020 HR steel
- 7,850 kg/m³
- Mild steel
- 7,870 kg/m³
- Stainless steel 304
- 7,930 kg/m³
- 03
Step 3: Get Instant Weight (kg or lbs)
Read the total from the result panel, which updates on every keystroke. Add a quantity for the lot weight and a price per kilogram for a costed line, then copy the whole estimate as plain text straight into a quotation.
2000 × 1000 × 10 mm, mild steel
157 kg
346.1 lb · 0.157 t
- g
- kg
- t
- lb
- US ton
- long ton
Results are theoretical masses. Mill rolling tolerances to ASTM A6/A6M or EN 10029 can move delivered weight by a few percent.
The formula
Steel Plate Weight Formula (Worked Example)
The steel plate weight formula is weight = volume × density, and for a rectangular plate that expands to weight = length × width × thickness × density. Every other blank shape changes only how the area is found.
Steel plate weight formula
weight = length × width × thickness × density
W = L × W × T × ρ
Worked example, metric
A 2000 × 1000 mm mild steel plate, 10 mm thick, weighs 157 kg.
volume = 2.0 m × 1.0 m × 0.01 m
volume = 0.02 m³
weight = 0.02 m³ × 7,850 kg/m³
weight = 157 kg
Order 12 of them and the lot weighs 1,884 kg (1.88 t, 4,154 lb), enough to change which forklift moves it.
Worked example, imperial
A 4 × 8 ft sheet of ¼ inch steel plate weighs 326.7 lb (148.2 kg).
area = 4 ft × 8 ft = 32 ft² (2.9729 m²)
¼ in = 6.35 mm
6.35 × 7.85 = 49.85 kg/m²
weight = 2.9729 m² × 49.85 kg/m²
weight = 148.2 kg = 326.7 lb
Working in pounds per cubic inch instead, mild steel is 0.2836 lb/in³ and the answer lands in the same place.
The shortcut estimators memorise
For steel, kilograms per square metre equals thickness in millimetres multiplied by 7.85. A 10 mm plate is 78.5 kg/m². A 6 mm plate is 47.1 kg/m². Multiply kg/m² by 0.2048 to reach pounds per square foot, so 10 mm plate is 16.08 lb/ft².
Rectangular plate
L × W × T × ρ
The plain case.
Round disc
π/4 × D² × T × ρ
Diameter, not radius.
Ring (annulus)
π/4 × (D² − d²) × T × ρ
Subtract the bore.
Triangular plate
½ × B × H × T × ρ
Base times height, halved.
Before you quote
Common Steel Plate Weight Calculation Mistakes To Avoid
Seven mistakes account for almost every wrong steel plate weight. Five are unit or density errors that a second look catches. Two are pricing habits that cost money quietly, order after order. Each one below carries the figure it costs and the correction.
- 01 1,000× out
Mixing units mid-calculation
Length in metres with thickness left in millimetres is the most common error. The arithmetic is correct and the answer is nonsense. Normalise every dimension to one unit before the formula runs.
Wrong: 2.0 m × 1.0 m × 10 20 m³ · 157 t
Right: 2.0 m × 1.0 m × 0.01 m 0.02 m³ · 157 kg
- 02 331 kg per 20 t
Using one density for every steel
Carbon steel is 7,840 kg/m³, stainless 304 is 7,930 and 316 is 7,980. Pricing a stainless order at carbon-steel density leaves real tonnage off the invoice.
Wrong: 20 t of 316 at 7.85 g/cm³ 20.000 t priced
Right: 20 t of 316 at 7.98 g/cm³ 20.331 t priced
- 03 33% overstated
Ignoring the bore on rings and flanges
A ring is not a disc. The bore is subtracted before the thickness is applied, and the diameters are squared — a bore at half the outer diameter removes a quarter of the weight.
Wrong: π/4 × 30² × 1.2 cm 6.66 kg
Right: π/4 × (30² − 15²) × 1.2 cm 4.99 kg
- 04 197 kg absorbed
Quoting net weight when you buy gross
The calculator returns finished-part weight. The stockholder invoices the plate they came out of. Divide net weight by the nesting yield and price that figure.
Wrong: 18.4 m² of finished parts 1,444 kg
Right: same parts at 88% nesting yield 1,641 kg
- 05 a few % per load
Treating theoretical mass as delivered weight
Every calculator returns nominal geometry × nominal density. Mills roll to a thickness tolerance under ASTM A6/A6M and EN 10029, and mill scale adds more. Quote on the calculated figure, settle against the mill certificate.
Wrong: invoice settled on the calculator disputed
Right: invoice settled on the mill certificate certified
- 06 25% spread
Reading gauge as if it were a unit
Gauge is an index into a table, and the table differs by metal. Higher numbers mean thinner material, and the steps are not linear. Convert to millimetres once and work from that.
Wrong: 16 gauge treated as one thickness 1 of 3 correct
Right: steel 1.519 · galv 1.613 · alu 1.291 mm
- 07 5.5% short
Substituting the nearest metric size
Half an inch is 12.700 mm, not 12 mm. Several common fractions sit around 5% from the nearest metric stock size, which is enough to fail a structural check.
Wrong: ½ in supplied as 12 mm 16.3 kg light per 4 × 8
Right: ½ in is 12.700 mm as specified
Reference data
Steel Density Chart By Grade
Steel density sits between 7,200 kg/m³ and 7,980 kg/m³ depending on grade. Carbon steel is 7,840 kg/m³, mild steel 7,870 kg/m³ and stainless 316 is 7,980 kg/m³. Adding carbon, chromium or nickel shifts the figure, which is why the grade has to be picked before the weight is calculated.
Density of iron and steel grades
Kilograms per cubic metre on a zoomed scale from 7,100 to 8,100 so the axis starts near the data rather than at zero. Hover or focus any row for its exact figure.
| Steel type | kg/m³ | g/cm³ | lb/in³ | lb/ft³ |
|---|---|---|---|---|
| Grey cast iron | 7,200 | 7.20 | 0.2601 | 449 |
| Stainless steel 430 | 7,700 | 7.70 | 0.2782 | 481 |
| Tool steel | 7,715 | 7.72 | 0.2787 | 482 |
| Wrought iron | 7,750 | 7.75 | 0.2800 | 484 |
| Carbon tool steel | 7,820 | 7.82 | 0.2825 | 488 |
| Cold-drawn steel | 7,830 | 7.83 | 0.2829 | 489 |
| Carbon steel | 7,840 | 7.84 | 0.2832 | 489 |
| C1020 HR steel | 7,850 | 7.85 | 0.2836 | 490 |
| Mild steel ASTM A36 | 7,850 | 7.85 | 0.2836 | 490 |
| Pure iron | 7,860 | 7.86 | 0.2840 | 491 |
| Mild steel | 7,870 | 7.87 | 0.2843 | 491 |
| Stainless steel 304 | 7,930 | 7.93 | 0.2865 | 495 |
| Stainless steel 316 | 7,980 | 7.98 | 0.2883 | 498 |
Published references quote plain carbon steels anywhere from 7,840 kg/m³ to 7,870 kg/m³. The spread is under 0.4 %, which moves a 24 tonne load by roughly 90 kg. Use the figure on the mill certificate where a contractual weight depends on it.
Weight tables
Common Steel Plate Weight Chart
A ¼ inch steel plate weighs 10.21 lb per square foot (49.85 kg/m²), and a 10 mm plate weighs 78.5 kg per square metre (16.08 lb/ft²). Both tables below run on carbon steel at 7,850 kg/m³ (7.85 g/cm³).
Steel plate weight per square foot
Fractional thicknesses, with the weight of a full 4 × 8 ft sheet (32 ft²).
| Thickness | mm | lb/ft² | kg/m² | 4 × 8 sheet |
|---|---|---|---|---|
| 1/8 in | 3.175 | 5.10 | 24.92 | 163.4 lb |
| 3/16 in | 4.762 | 7.66 | 37.39 | 245.0 lb |
| 1/4 in | 6.350 | 10.21 | 49.85 | 326.7 lb |
| 5/16 in | 7.938 | 12.76 | 62.31 | 408.4 lb |
| 3/8 in | 9.525 | 15.31 | 74.77 | 490.1 lb |
| 7/16 in | 11.112 | 17.87 | 87.23 | 571.7 lb |
| 1/2 in | 12.700 | 20.42 | 99.70 | 653.4 lb |
| 5/8 in | 15.875 | 25.52 | 124.62 | 816.8 lb |
| 3/4 in | 19.050 | 30.63 | 149.54 | 980.1 lb |
| 7/8 in | 22.225 | 35.73 | 174.47 | 1,143.5 lb |
| 1 in | 25.400 | 40.84 | 199.39 | 1,306.8 lb |
| 1 1/4 in | 31.750 | 51.05 | 249.24 | 1,633.5 lb |
| 1 1/2 in | 38.100 | 61.26 | 299.08 | 1,960.2 lb |
Steel plate weight per square metre
Stock thicknesses, with two standard plate sizes worked out in full.
| Thickness | kg/m² | lb/ft² | 2000 × 1000 | 3000 × 1500 |
|---|---|---|---|---|
| 3 mm | 23.55 | 4.82 | 47.1 kg | 106.0 kg |
| 4 mm | 31.40 | 6.43 | 62.8 kg | 141.3 kg |
| 5 mm | 39.25 | 8.04 | 78.5 kg | 176.6 kg |
| 6 mm | 47.10 | 9.65 | 94.2 kg | 212.0 kg |
| 8 mm | 62.80 | 12.86 | 125.6 kg | 282.6 kg |
| 10 mm | 78.50 | 16.08 | 157.0 kg | 353.3 kg |
| 12 mm | 94.20 | 19.29 | 188.4 kg | 423.9 kg |
| 16 mm | 125.60 | 25.72 | 251.2 kg | 565.2 kg |
| 20 mm | 157.00 | 32.16 | 314.0 kg | 706.5 kg |
| 25 mm | 196.25 | 40.20 | 392.5 kg | 883.1 kg |
| 30 mm | 235.50 | 48.23 | 471.0 kg | 1,059.8 kg |
| 40 mm | 314.00 | 64.31 | 628.0 kg | 1,413.0 kg |
| 50 mm | 392.50 | 80.39 | 785.0 kg | 1,766.3 kg |
Multiply any figure by a density ratio to reach another metal. Stainless 304 is 1.010 × carbon steel, aluminium 6061 is 0.344 ×, and copper is 1.141 ×. A 10 mm aluminium plate therefore weighs 27.0 kg/m², not 78.5 kg/m².
Plate weight reference charts
Mild Steel ASTM A36: kilograms per square metre by thickness
Hover or focus a bar for the exact figure.
Values are calculated, not measured. Always confirm against the mill certificate for contractual weights.
Density of commonly stocked metals
Bars show grams per cubic centimetre. Your selected alloy is highlighted.
What you get
Why Choose Our Steel Plate Weight Calculator
There are 5 reasons estimators keep this steel plate weight calculator open: it costs nothing, it carries 37 densities, it applies the engineering formula without shortcuts, it accepts mixed units in both directions, and it hands the result back in a form you can paste into a quote.
- 01
Free - No Sign-Up Required
The calculator is free, with no account, no email and no usage limit.
Every calculation runs in your browser. Dimensions, grades, quantities and prices stay on your device and reach no server, which is why a cutting list can be priced on a shop-floor connection that keeps dropping.
Nothing leaves your device
- 02
Multiple Grades & Alloys Supported
37 densities ship with the calculator, across 5 material families.
Carbon and alloy steel, stainless, non-ferrous metals, engineering plastics and the classic reference grades - tool steel, wrought iron, carbon tool steel, cold-drawn steel, C1020 HR steel and pure iron. Anything missing goes in as a custom density.
37 densities · 5 families
- 03
Engineering-Accurate Formula
Volume × density, with no rounding until the result is displayed.
Rectangles use L × W × T, discs use π/4 × D², rings subtract the bore, and triangles use ½ × B × H. Results are theoretical mass, and the interface says so.
4 geometries · exact arithmetic
- 04
Works in mm/Inches & kg/lbs - Both Directions
Every dimension carries its own unit, so drawings go in as they are dimensioned.
Length in metres, thickness in millimetres and a bore in inches can sit in one calculation. Output reads in grams through to imperial long tons.
5 length units · 6 weight units
- 05
Printable / Exportable Results
One button copies the shape, dimensions, grade, formula and total as plain text.
The copied block pastes straight into a quotation, an email or a job sheet. The reference tables print as they appear on screen.
Copy as plain text
FAQ
Frequently Asked Questions
The questions our estimating desk answers most often about steel plate weight, densities, standard sizes and the numbers that follow from them.
How much does a ¼-inch steel plate weigh per square foot?
How much does a 4×8 steel plate weigh?
What is the standard size of a steel plate?
What is the density of steel?
How do I calculate the Max bending force for a metal plate?
How to calculate yield strength of a steel plate?
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