diff --git a/pages/Configuring/Master-Layout.md b/pages/Configuring/Master-Layout.md
index 63436af1..8d09578b 100644
--- a/pages/Configuring/Master-Layout.md
+++ b/pages/Configuring/Master-Layout.md
@@ -11,6 +11,7 @@ _category name `master`_
 | name | description | type | default |
 |---|---|---|---|
 | special_scale_factor | (0.0 - 1.0) the scale of the special workspace windows | float | 0.8 |
+| mfact | (0.0 - 1.0) master split factor, the ratio of master split| float | 0.55 |
 | new_is_master | whether a newly open window should replace the master or join the slaves. | bool | true |
 | new_on_top | whether a newly open window should be on the top of the stack | bool | false |
 | no_gaps_when_only | whether to apply gaps when there is only one window on a workspace, aka. smart gaps. | bool | false |