diff --git a/blueprintcompiler/utils.py b/blueprintcompiler/utils.py
index 1c69fd9..5e939c7 100644
--- a/blueprintcompiler/utils.py
+++ b/blueprintcompiler/utils.py
@@ -74,9 +74,8 @@ def did_you_mean(word: str, options: T.List[str]) -> T.Optional[str]:
 def idx_to_pos(idx: int, text: str) -> T.Tuple[int, int]:
     if idx == 0 or len(text) == 0:
         return (0, 0)
-    sp = text[:idx].splitlines(keepends=True)
-    line_num = len(sp)
-    col_num = len(sp[-1])
+    line_num = text.count("\n", 0, idx) + 1
+    col_num = idx - text.rfind("\n", 0, idx) - 1
     return (line_num - 1, col_num)
 
 
diff --git a/tests/sample_errors/no_import_version.err b/tests/sample_errors/no_import_version.err
index 4ee792f..db830e0 100644
--- a/tests/sample_errors/no_import_version.err
+++ b/tests/sample_errors/no_import_version.err
@@ -1 +1 @@
-1,10,0,Expected a version number for GTK
+1,11,0,Expected a version number for GTK