diff --git a/.vscode/settings.json b/.vscode/settings.json
index 3911202d..25106104 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -4,6 +4,6 @@
   "javascript.implicitProjectConfig.checkJs": true,
   "javascript.validate.enable": true,
   "editor.codeActionsOnSave": {
-    "source.fixAll.eslint": true
+    "source.fixAll.eslint": "explicit"
   }
 }
diff --git a/lib/grades/gradeFormat.ts b/lib/grades/gradeFormat.ts
index f0404fc7..23114b69 100644
--- a/lib/grades/gradeFormat.ts
+++ b/lib/grades/gradeFormat.ts
@@ -8,6 +8,9 @@ Agrega puntos, comas, caracteres antes o despues de la nota.
  * @example const formated = gradeFormat(scale, grade)
  */
 export const gradeFormat = (scale: ScaleAttributes, grade: number): string => {
+  if (grade === null) {
+    grade = 0
+  }
   let round = `${gradeRound(scale, grade)}`
 
   if (round.length === 1 && scale.append === '' && scale.base !== 'Peru') {
diff --git a/lib/grades/gradeRound.ts b/lib/grades/gradeRound.ts
index ccf39902..6a441122 100644
--- a/lib/grades/gradeRound.ts
+++ b/lib/grades/gradeRound.ts
@@ -8,6 +8,9 @@ import { ScaleAttributes } from '../types'
 export const gradeRound = (scale: ScaleAttributes, grade: number): number => {
   try {
     let rounded: number | string
+    if (grade === null) {
+      return Number(0)
+    }
     if (scale.decimals > 0) {
       if (scale.decimals === 1) {
         rounded = Number(