My digital caliper displays units smaller than an inch in decimals. That's fine for the units like 1/4 inch displaying as .25 inches. But things get sticky with finer fractions. Quick: what's the decimal equivalent of 17/64? Sure, I could figure it out, but I usually don't.
The little gem shown here is a digital caliper that displays units in fractions on the screen. It has three modes: fractional inches, decimal inches, and millimeters.
As with most calipers, you can take inside measurements, outside measurements, and depth readings. It even shuts itself off after it's been idle for while to save battery life. (Mine doesn't do that.)
The Fractional Digital Caliper is available at Hartville Tool online.
While you are there, you should browse the clearance section. There truly are some good deals there.
The 6'' Fractional Digital Caliper is also available at Rockler Woodworking.