diff --git a/binding/form.go b/binding/form.go
index 557333e..0be5966 100644
--- a/binding/form.go
+++ b/binding/form.go
@@ -6,6 +6,8 @@ package binding
 
 import "net/http"
 
+const defaultMemory = 32 * 1024 * 1024
+
 type formBinding struct{}
 type formPostBinding struct{}
 type formMultipartBinding struct{}
@@ -18,7 +20,7 @@ func (formBinding) Bind(req *http.Request, obj interface{}) error {
 	if err := req.ParseForm(); err != nil {
 		return err
 	}
-	req.ParseMultipartForm(32 << 10) // 32 MB
+	req.ParseMultipartForm(defaultMemory)
 	if err := mapForm(obj, req.Form); err != nil {
 		return err
 	}
@@ -44,7 +46,7 @@ func (formMultipartBinding) Name() string {
 }
 
 func (formMultipartBinding) Bind(req *http.Request, obj interface{}) error {
-	if err := req.ParseMultipartForm(32 << 10); err != nil {
+	if err := req.ParseMultipartForm(defaultMemory); err != nil {
 		return err
 	}
 	if err := mapForm(obj, req.MultipartForm.Value); err != nil {