diff --git a/src/sv/nit.ts b/src/sv/nit.ts
index 8e3fce36..631dfec2 100644
--- a/src/sv/nit.ts
+++ b/src/sv/nit.ts
@@ -84,7 +84,7 @@ const impl: Validator = {
     let sum;
     const [front, check] = strings.splitAt(value, 13);
 
-    if (value.substr(10, 3) === '100') {
+    if (value.slice(10, 13) <= '100') {
       sum =
         weightedSum(front, {
           weights: [14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2],
@@ -92,11 +92,12 @@ const impl: Validator = {
         }) % 10;
     } else {
       sum =
-        (11 -
+        ((11 -
           weightedSum(front, {
             weights: [2, 7, 6, 5, 4, 3, 2, 7, 6, 5, 4, 3, 2],
             modulus: 11,
           })) %
+          11) %
         10;
     }