Metal Stock Calculator

Material loss happens throughout the whole piece — scale flakes off every heated surface, grinding removes stock everywhere you shape it, and cuts happen at both ends — so it's modeled as a percentage of total volume rather than a fixed length tacked onto one end. Multiplying the finished volume by (1 + loss% ÷ 100) scales the whole piece proportionally, then dividing by the stock bar's cross-section converts that inflated volume back into a length you can actually measure and cut.

The calculator's default of 15% sits between the two ranges it's built around: 10-20% for hand forging with an open flame, where scale forms continuously as the bar is heated and hammered, and 5-10% for stock removal, where you start closer to final dimensions and grind rather than forge to shape. If your project involves a lot of shape change — like drawing a thick billet into a thin blade — lean toward the higher end, since more heat cycles and more exposed surface area both mean more scale.

No — the calculator multiplies volume by a flat 0.283 lb per cubic inch, which is the density of mild and most tool steels, so weight figures for stainless (slightly denser) or copper alloys and aluminum (significantly different density) will be off. The length and volume figures are unaffected since they don't depend on density; only the two weight outputs would need a different density constant for other metals.

No — the calculator only conserves volume, not shape. It tells you how much raw volume of stock you need to end up with the finished piece's volume after losses, but it doesn't simulate the actual forging sequence of drawing out, tapering, or upsetting the bar. You still need to plan your own forging steps to get from the starting bar shape to the finished geometry; this just tells you how long that starting bar should be.