Enter the blade you're planning and get the bar to buy, how many blades a bar yields, and what the steel costs per blade. Works for forged and stock-removal knives.
Steel is only part of the cost. Add abrasives, handle, heat treat and your time, and see the price that actually pays you.
Copy link to this calculationBar sizes for ten common knife patterns, weight per inch for every standard flat bar, and quick heat-treat numbers for the usual carbon steels. Print it, tape it to the grinder.
Bar width is your blade height at the ricasso plus 1/8 in of clean-up, rounded up to the next standard width — the same rule most experienced smiths use. Thickness is your finished spine, rounded up to the next standard bar thickness.
Forged blades are worked out two ways and the larger answer wins: by volume (the finished blade and tang estimated from your dimensions, plus the allowance for scale and grinding, divided by the bar's cross-section), and by stretch (forging bevels and a point grows the blade by roughly a third, a hidden or stick tang is drawn out to several times its starting length, a full tang hardly moves). Drawing out is why forged knives use noticeably less bar than stock removal.
Stock removal simply needs a piece long enough for blade plus tang, plus the cut-off. Everything ground away is counted as waste, which is why the waste figure is higher.
Sanity check: a student's account of an ABS intro class (ABS forum, Nov 2013) lists a 4 in drop point forged from 1 × 1/4 in, a 7 in blade from 1¼ × 1/4 in, and the 10 in test knife from 1½ × 1/4 in; a Master Smith in the same thread forges most knives from 1/4 in bar with a width about 1/8 in over the ricasso. The calculator lands on the same answers. Forging stretch and tang draw ratios are this tool's own estimates, not measured data — check them against your first few bars.
Weights and prices use nominal bar size and September 2026 retail prices from knife-steel suppliers. Hot-rolled bar from most suppliers ships oversize (a nominal 1/8 in bar often measures 0.135–0.155 in), so real weight and cost can run 8–18% higher than shown; precision-ground stock is on size.