Engineering reference · Forged rings, discs and blocks
Forging Weight Calculator for Rings, Discs and Blocks
Pick the shape, enter its size and choose the steel. The calculator gives the weight of one piece in kg and lb, and the total for your quantity, with the volume and the formula it used.
Weight
Weight of one piece
The part, in proportion
Loading the 3D model...
Drag to turn it any way, or use Front, Side and 3/4; on a phone, swipe sideways to turn. Scroll to zoom. Drawn in proportion to the sizes you entered.
Read this before you use the number
- This is the weight of the shape you enter. If you enter finished-part dimensions, the as-forged weight is higher, because we add forging and machining allowances to the finished size. We set those allowances per drawing.
- The densities are nominal. They are values for the grade family. The actual weight of a part varies slightly with its chemistry and its tolerances.
How the weight is worked out
The calculator finds the volume of the shape from the dimensions you enter, then multiplies it by the density of the steel. For a part that is not one of the three shapes, such as a ring with a stepped or tapered section, work out the volume of each simple part and add them, or send us the drawing.
- Ring or hollow cylinder: volume = π/4 × (OD² − ID²) × height.
- Solid disc or round bar: volume = π/4 × diameter² × length (the thickness, for a disc).
- Rectangular block or plate: volume = length × width × thickness.
- Weight: volume × density. With the volume in cm³ and the density in g/cm³, weight in kg = volume × density ÷ 1,000. The total is the weight of one piece × the quantity.
- Units: 1 in = 25.4 mm and 1 kg = 2.2046 lb. Inch input is converted to mm before the volume is calculated.
Typical densities
| Material | Typical grades | g/cm³ | kg/m³ | lb/in³ |
|---|---|---|---|---|
| Carbon and low-alloy steel | A105, A350 LF2, A694 F65 | 7.85 | 7,850 | 0.2836 |
| Cr-Mo alloy steel | F11, F22, F91 | 7.85 | 7,850 | 0.2836 |
| Austenitic stainless 304 / 304L | F304, F304L | 7.93 | 7,930 | 0.2865 |
| Austenitic stainless 316 / 316L | F316, F316L | 7.98 | 7,980 | 0.2883 |
| Duplex 2205 | F51, F60 | 7.80 | 7,800 | 0.2818 |
| Super duplex | F53, F55 | 7.80 | 7,800 | 0.2818 |
Nominal values for the grade family. For a grade that is not listed, or a density your specification gives, use the custom density field.
Why the as-forged weight is higher than the finished weight
A forging is made oversize on every surface that will be machined. The extra metal, the machining allowance, is cut away later, so the as-forged piece is heavier than the finished part. A ring is forged with a larger OD and a smaller ID than the finished ring, and a disc is forged larger and thicker than the finished disc.
The allowance depends on the size and shape of the part, the grade and the heat treatment, so we set it per drawing and this calculator does not guess it. Enter finished dimensions and you get the finished weight. Enter as-forged dimensions and you get the as-forged weight. When you compare weights between suppliers, check which of the two each figure is.
What to send with an RFQ for a ring or disc forging
- The drawing, if you have one.
- Material grade and specification, for example ASTM A182 F316L.
- Dimensions, finished or as-forged, with tolerances. Say which you are giving.
- Quantity.
- Heat treatment condition.
- The testing and certificate type you need.
- Destination port.
Our product pages cover these parts in more detail: Custom Forged Rings for rolled and open-die rings, Tube Sheet Forgings for round plates and discs, and Non-Standard Forgings for parts made to your drawing.
Reference only. This calculator is a buying aid, not a quotation. Formulas and densities checked 2026-10-14.