A clamp meter (clamp-on ammeter) is a type of ammeter which measures electrical current without the need to disconnect the wiring through which the current is flowing.

Clamp meters are also known as tong testers or Amprobes, (after one of the first vendors of such devices).

The most common forms of clamp meter are:

• A probe for use with a multimeter.
• A self-contained unit.
• A built-in part of a specialised multimeter used by electricians.