diff --git a/private/format-utils.rkt b/private/format-utils.rkt
index 2ec1d62..8f36d9f 100644
--- a/private/format-utils.rkt
+++ b/private/format-utils.rkt
@@ -148,7 +148,7 @@
               ([pair c])
       (match pair
         [(list m (srcloc _ _ _ start range))
-         (if (and (<= start loc (+ start range))
+         (if (and (<= start loc (+ start range -1))
                   (or (eq? mode 'none)
                       (> start last-start)))
              (values m start)