LinuxCNC G93

G93 selects inverse time feed rate mode in LinuxCNC. In this mode an F word sets the duration of a move: the move is completed in one divided by the F number minutes, so F2.0 finishes the move in half a minute. It does not affect G0 rapid moves; G94 (units per minute) and G95 (units per revolution) are the other feed rate modes.

Source checked4/4 values · 2026-10-26

Specification

1 source

Language	gcode
Code	G93
Group	Feed Rate Mode
Dialect	LinuxCNC

Parameters

Name	Description
F	Inverse time value: the move is completed in 1 divided by the F number minutes (F2.0 means half a minute).

Study notes

Inverse time mode requires an F word on every line that has a G1, G2 or G3 motion, whether explicit or implicit.
An F word on a line without G1, G2 or G3 is ignored while inverse time mode is active.
Inverse time feed rate mode does not affect G0 rapid moves.
It is an error if inverse time feed mode is active and a line with G1, G2 or G3 does not have an F word.
It is an error if a new feed rate is not specified after switching to G94 or G95.
G93 belongs to the feed rate mode group with G94 (units per minute) and G95 (units per revolution).