There are more varieties of putters on the market than any other club. That may be because choosing a putter is a very personal process. There is no "right" putter. There is simply the putter that is right for you.
Putters generally come in three styles of clubhead, and three varieties of lengths.
Clubheads can be a traditional blade; a heel-toe clubhead; or a mallet clubhead. A traditional blade is narrow and shallow, typically with the shaft entering at the heel (although sometimes center-shafted). Low-handicappers might like traditional blades because they offer great feedback, but most golfers are better off staying away from blades. They offer very little forgiveness.
Beginning golfers will want putters that are plenty forgiving, meaning they help cover up for mis-hits and poor strikes. Heel-toe putters have the same general shape as blades, but with extra eight at the heel and toe to add perimeter weighting, and with other design tricks (hollow back, wider flange, face inserts) to help boost MOI.
Mallet putters have large clubheads that maximize moment of inertia for the most forgiving putter heads. Mallets come in a variety of shapes and sizes, some of the very large and quite unusual.
Lengths are standard, often referred to as a "conventional putter," and standard lengths range from around 32 to 36 inches. Standard, or conventional, length is the most popular and is the length that beginners should start with.
How do standard (conventional), belly and broomstick putters compare? See our article on finding the right putter length), but the basic advice is to start with a standard putter and move on to a long putter only if you can't improve with the conventional.
But what putters boil down to is personal choice. If it feels good to you when you are using a putter, then that putter will probably work just fine. So much of putting is confidence, so having a putter that feels good, that you simply like, can only be a good thing.
Putters are, of course, designed to be used on the putting green. However, it isn't uncommon for golfers to use their putters from up to a few yards off the putting green, if the turf around the green is cut very low. The key to using a putter from off the putting surface is a low, smooth cut of turf. The fringe or frog hair that circles a green usually qualifies.
All putters, regardless of size or shape, are designed to start the ball rolling smoothly, with a minimum of backspin to avoid skipping or skidding. Almost all putters have a small amount of loft (typically 3 or 4 degrees), so the ball does come up off the turf when it is first struck, then settles back on the surface of the putting green and begins its forward roll.
For instructional articles on how to use your putters, see: