diff --git a/docs/reference-guides/core-blocks.md b/docs/reference-guides/core-blocks.md
index c8be3221198b4..8457f71256550 100644
--- a/docs/reference-guides/core-blocks.md
+++ b/docs/reference-guides/core-blocks.md
@@ -590,7 +590,7 @@ Show minutes required to finish reading the post. ([Source](https://github.com/W
 
 -	**Name:** core/post-time-to-read
 -	**Category:** theme
--	**Supports:** typography (fontSize, lineHeight), ~~html~~
+-	**Supports:** spacing (margin, padding), typography (fontSize, lineHeight), ~~html~~
 -	**Attributes:** textAlign
 
 ## Post Title
diff --git a/packages/block-library/src/post-time-to-read/block.json b/packages/block-library/src/post-time-to-read/block.json
index a6129f6bb672f..20313744c343e 100644
--- a/packages/block-library/src/post-time-to-read/block.json
+++ b/packages/block-library/src/post-time-to-read/block.json
@@ -15,6 +15,10 @@
 	},
 	"supports": {
 		"html": false,
+		"spacing": {
+			"margin": true,
+			"padding": true
+		},
 		"typography": {
 			"fontSize": true,
 			"lineHeight": true,
diff --git a/packages/block-library/src/post-time-to-read/style.scss b/packages/block-library/src/post-time-to-read/style.scss
new file mode 100644
index 0000000000000..9d10408a599ed
--- /dev/null
+++ b/packages/block-library/src/post-time-to-read/style.scss
@@ -0,0 +1,4 @@
+.wp-block-post-time-to-read {
+	// This block has customizable padding, border-box makes that more predictable.
+	box-sizing: border-box;
+}
diff --git a/packages/block-library/src/style.scss b/packages/block-library/src/style.scss
index a7f12e74ea2f5..96884f9887df9 100644
--- a/packages/block-library/src/style.scss
+++ b/packages/block-library/src/style.scss
@@ -32,6 +32,7 @@
 @import "./post-featured-image/style.scss";
 @import "./post-navigation-link/style.scss";
 @import "./post-terms/style.scss";
+@import "./post-time-to-read/style.scss";
 @import "./post-title/style.scss";
 @import "./preformatted/style.scss";
 @import "./pullquote/style.scss";