diff --git a/packages/style-value-parser/src/css-types/__tests__/basic-shape.js b/packages/style-value-parser/src/css-types/__tests__/basic-shape.js
index a4f30c77f..06916a8a3 100644
--- a/packages/style-value-parser/src/css-types/__tests__/basic-shape.js
+++ b/packages/style-value-parser/src/css-types/__tests__/basic-shape.js
@@ -62,6 +62,23 @@ describe('Basic Shapes', () => {
       expect(() => Inset.parser.parseToEnd('inset(invalid)')).toThrow();
       expect(() => Inset.parser.parseToEnd('inset(10px, invalid)')).toThrow();
     });
+
+    it('should stringify the shortest valid form', () => {
+      const roundtrip = (css: string): string =>
+        Inset.parser.parseToEnd(css).toString();
+      // 1 value: all four sides equal.
+      expect(roundtrip('inset(10px)')).toBe('inset(10px)');
+      // 2 values: vertical / horizontal.
+      expect(roundtrip('inset(10px 20px)')).toBe('inset(10px 20px)');
+      // 3 values: top / horizontal / bottom (left === right).
+      expect(roundtrip('inset(10px 20px 30px)')).toBe('inset(10px 20px 30px)');
+      // 4 values: all distinct (no trailing space before the paren).
+      expect(roundtrip('inset(10px 20px 30px 40px)')).toBe(
+        'inset(10px 20px 30px 40px)',
+      );
+      // round radius is preserved.
+      expect(roundtrip('inset(10px round 5px)')).toBe('inset(10px round 5px)');
+    });
   });
 
   describe('Circle', () => {
diff --git a/packages/style-value-parser/src/css-types/basic-shape.js b/packages/style-value-parser/src/css-types/basic-shape.js
index e69bdc5a8..f6eb5cd86 100644
--- a/packages/style-value-parser/src/css-types/basic-shape.js
+++ b/packages/style-value-parser/src/css-types/basic-shape.js
@@ -41,24 +41,19 @@ export class Inset extends BasicShape {
   }
   // Stringify the shortest possible version of the inset
   toString(): string {
-    const { top, right, bottom, left, round } = this;
+    const { top, right, bottom, left } = this;
     const roundStr =
       this.round != null ? ` round ${this.round.toString()}` : '';
-    if (
-      top === right &&
-      right === bottom &&
-      bottom === left &&
-      left === round
-    ) {
+    if (top === right && right === bottom && bottom === left && left === top) {
       return `inset(${top.toString()}${roundStr})`;
     }
     if (top === bottom && left === right) {
       return `inset(${top.toString()} ${right.toString()}${roundStr})`;
     }
-    if (top === bottom) {
+    if (left === right) {
       return `inset(${top.toString()} ${right.toString()} ${bottom.toString()}${roundStr})`;
     }
-    return `inset(${top.toString()} ${right.toString()} ${bottom.toString()} ${left.toString()} ${roundStr})`;
+    return `inset(${top.toString()} ${right.toString()} ${bottom.toString()} ${left.toString()}${roundStr})`;
   }
 
   static get parser(): TokenParser<Inset> {