---
tag: m0900
title: Linear Advance Factor
brief: Get and set Linear Advance K value
author: thinkyhead

requires: LIN_ADVANCE
group: control

codes: [ M900 ]

notes: See [Linear Advance](/docs/features/lin_advance.html) for details on how to determine the K factor and a link to our calibration tool.

parameters:
  -
    tag: K
    optional: true
    description: |
      The K factor to set for the specified extruder. Unchanged if omitted. Set this value higher for more flexible filament or a longer filament path.

      With `EXTRA_LIN_ADVANCE_K` this sets the *primary* K factor. Note that this factor may be inactive and won't take effect until the next `M900 S0`.
    values:
      -
        tag: kfactor
        type: float
  -
    tag: L
    since: 2.0.0
    optional: true
    description: Set the second K factor for the specified extruder. Requires `EXTRA_LIN_ADVANCE_K`. Note that this factor may be inactive and won't take effect until the next `M900 S1`.
    values:
      -
        tag: kfactor
        type: float
  -
    tag: S
    since: 2.0.0
    optional: true
    description: Select slot and activate the last stored value. Requires `EXTRA_LIN_ADVANCE_K`.
    values:
      -
        tag: slot
        type: int
  -
    tag: T
    since: 2.0.0
    optional: true
    description: Extruder to which `K`, `L`, and `S` will apply. Requires `EXTRA_LIN_ADVANCE_K`.
    values:
      -
        tag: index
        type: int

videos:
  - n3yK0lJ8TWM
  - _BiqlXPPfu4

examples:
  -
    pre: Fetch the K factor
    code: M900
  -
    pre: Set the K factor
    code: M900 K0.18
  -
    pre: Disable Linear Advance
    code: M900 K0
  -
    pre: "`EXTRA_LIN_ADVANCE_K` adds an extra storage slot."
    code: |
      M900 S0            ; Select main K factor and apply it
      M900 T2 K0.22 L0.4 ; Set both T2 K factors. K0.22 will be applied.
      M900 T2 S1         ; Select extra K factor. L0.4 will be applied.
      M900 T2 S1         ; (does nothing this time)
      M900 T2 L0.3       ; Set T2 extra (and active) K factor
      ...
      M900 T2 S0         ; Select main K factor (0.22)

---

This command sets and/or reports the Linear Advance K factors.

Setting the K factor to 0 disables Linear Advance.

With the `EXTRA_LIN_ADVANCE_K` option Marlin maintains two slots for each extruder. The first slot is set with `K` and the second slot is set with `L`, then select the first using `S0` and the second using `S1`.