diff --git a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/logging/TLogger.java b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/logging/TLogger.java
index 73e7224a6b..bf33555f27 100644
--- a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/logging/TLogger.java
+++ b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/logging/TLogger.java
@@ -86,7 +86,7 @@ private TString format(TString message, Object[] params) {
                 index = next;
                 continue;
             }
-            int paramIndex = TInteger.parseInt(message.substring(index, next - 1));
+            int paramIndex = TInteger.parseInt(message.substring(paramStart, next));
             if (paramIndex >= params.length) {
                 sb.append(message.substring(index, next));
                 index = next;