For most knives you need a single billet a little larger than the finished blade: as wide as the knife's tallest point plus a millimeter or two, as thick as the job calls for (2 to 2.5 mm for kitchen knives, 3 to 4 mm for hunters), and as long as the knife's overall length for a full tang. Buying Damascus cut to the inch means you order exactly that billet and pay only for the steel you use, instead of buying an oversized fixed block and wasting the rest.
The trouble with fixed-size billets
Most Damascus is sold in set sizes: a supplier lists a 10 by 2 inch blank, a 12 by 1.5, and you pick the nearest one that fits. If your knife is smaller, you pay for steel you grind into the bin. If it falls between sizes, you buy the next one up. And if you want a long chef's knife or an unusually tall profile, the size you need may not be on the shelf at all.
For a material priced by weight, paying for waste adds up fast.
Cut to the inch: pay for what you use
Damaworks cuts DSC® Carbon and DSC® Inox to the length you order, priced per inch, in the width and thickness you choose. You buy a billet sized to your knife, not a block you have to cut down. Because the bars come flat-ground, very little is lost to cleanup, so the billet you order is close to the steel that ends up in the blade.
That also makes it easy to buy for a batch: order one length for three paring knives, or three separate billets for three different projects, each cut to its own size.
How much do you actually need?
Three measurements, taken from the knife you are building:
Width comes from the tallest point of the knife, measured spine to edge, plus a millimeter or two to clean up the profile. A chef's knife that is 50 mm tall at the heel wants about 55 mm stock.
Thickness comes from the knife's job. Rough starting points: 2 to 2.5 mm for kitchen knives, 2 to 4 mm for folders, 3 to 4 mm for hunting and skinning knives, 4 to 5 mm for bushcraft and camp knives. You can always grind thinner than the stock, never thicker.
Length comes from the whole knife. For a full tang, order the knife's overall length plus a little for cleanup. For a hidden tang, you need the blade plus whatever runs into the handle.
For the full walkthrough on picking dimensions, see How to choose a Damascus billet size.
A worked example
Say you are making an 8 inch (200 mm) chef's knife, 50 mm tall at the heel, full tang. You would order one DSC® billet about 55 mm wide, 2.5 mm thick, and roughly 210 mm long: wide enough for the profile with cleanup, thin enough for a kitchen slicer, and long enough for the full tang. One billet, cut to that length, with almost nothing wasted.
Order cut to size
Pick your steel, pattern, width, and thickness, set the length in inches, and the billet ships flat-ground and ready to profile. Start at the shop, or go straight to DSC® Carbon or DSC® Inox cut to the inch.