diff --git a/packages/core/src/propGetters.js b/packages/core/src/propGetters.js
index 498de463..f22f5052 100644
--- a/packages/core/src/propGetters.js
+++ b/packages/core/src/propGetters.js
@@ -99,16 +99,16 @@ export const propGetters = {
   'min-height': getNumberSize,
 
   // getZIndex
-  'z-index': getZIndex,
+  'z-index': getNumber(getZIndex),
 
   // getFont
   'font-family': getFont,
 
   // getFontSize
-  'font-size': getFontSize,
+  'font-size': getNumber(getFontSize),
 
   // getLineHeight
-  'line-height': getLineHeight,
+  'line-height': getNumber(getLineHeight),
 
   // getFontWeight
   'font-weight': getFontWeight,
diff --git a/packages/core/src/propGetters.test.js b/packages/core/src/propGetters.test.js
index 365aa4d7..045c9769 100644
--- a/packages/core/src/propGetters.test.js
+++ b/packages/core/src/propGetters.test.js
@@ -4,6 +4,7 @@ describe('#propGetters', () => {
   describe('border-radius', () => {
     it('handles several values', () => {
       expect(propGetters['border-radius']('10')({})).toBe('10px')
+      expect(propGetters['font-size']('10')({})).toBe('10px')
       expect(propGetters['border-radius']('1 2')({})).toBe('1px 2px')
       expect(
         propGetters['border-radius']('md')({ theme: { radii: { md: 10 } } }),