diff --git a/cast_test.go b/cast_test.go
index f9a24df..2c4e421 100644
--- a/cast_test.go
+++ b/cast_test.go
@@ -6,9 +6,9 @@
 package cast
 
 import (
-	"testing"
-
 	"html/template"
+	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -151,3 +151,12 @@
 	assert.Equal(t, ToInt(y), 13)
 	assert.Equal(t, ToInt(z), 13)
 }
+
+func TestToDuration(t *testing.T) {
+	a := time.Second * 5
+	ai := int64(a)
+	b := time.Second * 5
+	bf := float64(b)
+	assert.Equal(t, ToDuration(ai), a)
+	assert.Equal(t, ToDuration(bf), b)
+}
diff --git a/caste.go b/caste.go
index b8e6044..5401c0b 100644
--- a/caste.go
+++ b/caste.go
@@ -43,6 +43,12 @@
 	switch s := i.(type) {
 	case time.Duration:
 		return s, nil
+	case int64:
+		d = time.Duration(s)
+		return
+	case float64:
+		d = time.Duration(s)
+		return
 	case string:
 		d, err = time.ParseDuration(s)
 		return