There are a variety of knife blade shapes; some of the most common are listed below.
1. A normal or straightback blade has a curving edge, and flat back. A dull back lets the wielder use fingers to concentrate force; it also makes the knife heavy and strong for its size. The curve concentrates force on a small point, making cutting easier. This knife can chop as well as pick and slice.
2. A curved, trailing-point knife has a back edge that curves upward. This lets a lightweight knife have a larger curve on its edge. Such a knife is optimized for slicing or slashing. Trailing point blades provide a larger cutting area, or belly, and are common on skinning knives.
3. A clip-point blade is like a normal blade with the back "clipped" or concavely formed to make the tip thinner and sharper. The back edge of the clip may have a false edge that could be sharpened to make a second edge. The sharp tip is useful as a pick, or for cutting in tight places. If the false edge is sharpened it increases the knife's effectiveness in piercing. The Bowie knife has a clipped blade and clip-points are quite common on pocket knives and other folding knives.
4. A drop-point blade has a convex curve of the back towards the point. It handles much like the clip-point through with a stronger point less suitable for piercing. Swiss army pocket knives often have drop-points on their larger blades.
5. A spear-point blade is a symmetrical blade with a spine that runs along the middle of the blade. The point is in line with the spine. Spear-points may be single-edged (with a false edge) or double-edged or may have only a portion of the second edge sharpened. Pen-knives are often single-edged, non-spined spear-points, usually quite small, named for their past use in sharpening quills for writing. Pen-knife may also nowadays refer to somewhat larger pockets knives which are often drop-points. Some throwing knives may have spear-points but without the spine, being only flat pieces of metal.
6. A needle-point blade is a symmetrical, highly tapered, twin-edged blade often seen in fighting blades, such as the Fairbairn-Sykes commando knife. Its long, narrow point offers good penetration but is liable to breakage if abused. Although often referred to as a knife, this design may also be referred to as a stiletto or (slender variety of) dagger due to its use as a stabbing weapon albeit one very capable of slashing as well.
7. A spay-point (once used for spaying animals) has a single, mostly straight edge that curves strongly upwards at the end to meet a short, dull, straight clip from the dull back. With the curved end of the blade being closer to perpendicular to the blade's axis than other knives and lacking a point, making penetration unlikely, spay points can be suitable for skinning.
8. A Westernised tanto style knife has a somewhat chisel-like point that is thick towards the point (being close to the spine) and is thus quite strong. It is superficially similar to the points on most Japanese long and short swords ( katana and wakizashi ). The traditional Japanese tanto knife uses the blade geometry of (1). The Westernised tanto is often straight but may also be gently curved. The point is actually a second edge on the end of the blade, with a total edge angle of 60 – 80 degrees. Some varieties may have the back edge angled to the point slightly and sharpened for a short distance from the point.
9. A sheepsfoot knife has a straight edge and a straight dull back that curves towards the edge at the end. It gives the most control, because the dull back edge is made to be held by fingers. Sheepsfoot knives are good for whittling and trimming sheep's hooves.
10. A Wharncliffe blade is similar in profile to a sheep's foot but the curve of the back edge starts closer to the handle and is more gradual. Its blade is much thicker than a knife of comparable size.
11. and 12. An ulu (Inuit woman's knife) knife is a sharpened segment of a circle. This blade type has no point, and has a handle in the middle. It is good for scraping, and sometimes chopping. It is the strongest knife shape. The semi-circular version appears elsewhere in the world and is called a head knife. It is used in leatherworking both to scrape down leather (reducing thickness), and to make precise, rolling cuts for shapes other than straight lines.