diff --git a/tests/components/light/common.yaml b/tests/components/light/common.yaml
index c40cfd5e3a..046acef9ce 100644
--- a/tests/components/light/common.yaml
+++ b/tests/components/light/common.yaml
@@ -188,7 +188,7 @@ number:
       then:
         - light.turn_on:
             id: test_monochromatic_light
-            brightness: !lambda "return x / 100.0;"
+            brightness: !lambda "return x / 100.0f;"
 
 output:
   - platform: template