Material is usually the first line of a machining quote and the easiest one to get wrong, because you pay for the billet and ship the part. This calculator converts stock dimensions into mass, mass into cost, and shows how much of what you bought is going to end up in the chip conveyor.
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Material weight and stock cost calculator
Work out stock mass from dimensions and alloy density, then material cost and chip mass. All calculations stay in this browser.
Material and shape
Dimensions (mm)
Cost and removal
Density
2.70g/cm³Stock volume
960.0cm³Stock mass
2.592kgMaterial cost
PLN 72.58Chip mass
1.426kgFinished part mass
1.166kgPlanning model: volume × nominal density. Densities are room-temperature datasheet values — a real batch can differ, and bar or plate stock carries its own dimensional tolerances. The cost excludes cutting, delivery, minimum order quantities and any scrap credit recovered from the chips.
How it works
Mass = volume × density. The calculator computes volume from the shape you choose:
| Shape | Volume |
|---|---|
| Block or plate | length × width × height |
| Round bar | π × (Ø ÷ 2)² × length |
| Tube | π × ((OD ÷ 2)² − (ID ÷ 2)²) × length |
Dimensions are in millimetres, densities in g/cm³, and the result in kilograms. Density values are shown next to each material so you can check them against your own supplier data.
Removal rate and chip mass
The removal percentage is what turns a stock weight into a machining insight. A part cut from a solid block at 80% removal means four fifths of the material you paid for becomes swarf — and it also means a great deal of cutting time. A part at 15% removal is close to net shape and will usually machine far faster.
If the number surprises you, that is often the signal to ask whether a different stock size, a near-net blank or a casting would be cheaper overall.
Materials included
Aluminium 6061, 7075 and 5083; steel S235JR, C45 and 42CrMo4; stainless 1.4301 (304) and 1.4404 (316L); brass CuZn39Pb3; copper Cu-ETP; titanium Ti-6Al-4V; and the engineering plastics POM-C, PA6 and PEEK.
Limits
These are nominal densities, not certified values. Real stock carries dimensional tolerances of its own — plate is rarely exactly the thickness you ordered — so the calculated mass is a planning figure, not a weighbridge reading. Where an exact mass matters commercially, weigh the material.
The cost is simply mass × price per kilogram. It excludes cutting, delivery, minimum order quantities and any scrap credit you recover from the chips.
Once you have a stock mass, the CNC part cost calculator takes it and adds machining, setup and margin. For why material choice moves a quote so much, read what drives CNC machining cost.
Kostira reads the bounding box and stock size straight out of your STEP file, so this arithmetic happens automatically; see how it works.