diff --git a/content/build/building/env-vars.md b/content/build/building/env-vars.md
index 33f2f90776..8ade56cb24 100644
--- a/content/build/building/env-vars.md
+++ b/content/build/building/env-vars.md
@@ -10,10 +10,11 @@ You can set the following environment variables to enable, disable, or change
 the behavior of features related to building:
 
 | Variable                                                                    | Type              | Description                                          |
-| --------------------------------------------------------------------------- | ----------------- | ---------------------------------------------------- |
+|-----------------------------------------------------------------------------|-------------------|------------------------------------------------------|
 | [BUILDKIT_COLORS](#buildkit_colors)                                         | String            | Configure text color for the terminal output.        |
 | [BUILDKIT_HOST](#buildkit_host)                                             | String            | Specify host to use for remote builders.             |
 | [BUILDKIT_PROGRESS](#buildkit_progress)                                     | String            | Configure type of progress output.                   |
+| [BUILDKIT_TTY_LOG_LINES](#buildkit_tty_log_lines)                           | String            | Number of log lines (for active steps in tty mode).  |
 | [BUILDX_BUILDER](#buildx_builder)                                           | String            | Specify the builder instance to use.                 |
 | [BUILDX_CONFIG](#buildx_config)                                             | String            | Specify location for configuration, state, and logs. |
 | [BUILDX_EXPERIMENTAL](#buildx_experimental)                                 | Boolean           | Turn on experimental features.                       |
@@ -22,7 +23,7 @@ the behavior of features related to building:
 | [BUILDX_GIT_LABELS](#buildx_git_labels)                                     | String \| Boolean | Add Git provenance labels to images.                 |
 | [BUILDX_NO_DEFAULT_ATTESTATIONS](#buildx_no_default_attestations)           | Boolean           | Turn off default provenance attestations.            |
 | [BUILDX_NO_DEFAULT_LOAD](#buildx_no_default_load)                           | Boolean           | Turn off loading images to image store by default.   |
-| [EXPERIMENTAL_BUILDKIT_SOURCE_POLICY](#experimental_buildkit_source_policy)  | String           | Specify a BuildKit source policy file.               |
+| [EXPERIMENTAL_BUILDKIT_SOURCE_POLICY](#experimental_buildkit_source_policy) | String            | Specify a BuildKit source policy file.               |
 
 See also
 [BuildKit built-in build args](../../engine/reference/builder.md#buildkit-built-in-build-args).
@@ -80,6 +81,15 @@ Usage:
 $ export BUILDKIT_PROGRESS=plain
 ```
 
+## BUILDKIT_TTY_LOG_LINES
+
+You can change how many log lines are visible for active steps in tty mode by
+setting `BUILDKIT_TTY_LOG_LINES` to a number (default to `6`).
+
+```console
+$ export BUILDKIT_TTY_LOG_LINES=8
+```
+
 ## EXPERIMENTAL_BUILDKIT_SOURCE_POLICY
 
 Lets you specify a