diff --git a/src/lib.ts b/src/lib.ts
index e7c5f46..91f190a 100644
--- a/src/lib.ts
+++ b/src/lib.ts
@@ -22,7 +22,7 @@ export function tap<T>(value: any, interceptor: (v: any) => T) {
 export function normalizeDatabaseName(input: string) {
   return input
     .replace(/[\W_]+/g, '_')
-    .substring(0, 64)
+    .substring(0, 63)
     .replace(/^_|_$/g, '')
     .toLowerCase();
 }
diff --git a/tests/unit/lib.test.ts b/tests/unit/lib.test.ts
index 1c33989..10b59cd 100644
--- a/tests/unit/lib.test.ts
+++ b/tests/unit/lib.test.ts
@@ -58,7 +58,7 @@ describe('normalizeDatabaseName', () => {
     ['one! two? three 0x995', 'one_two_three_0x995'],
     ['jbk/px-454', 'jbk_px_454'],
     ["please+don't %20 do / this", 'please_don_t_20_do_this'],
-    ['a'.repeat(65), 'a'.repeat(64)],
+    ['a'.repeat(65), 'a'.repeat(63)],
     ['FOO bar', 'foo_bar'],
   ])('%s → %s', (input, output) => {
     expect(normalizeDatabaseName(input)).toBe(output);