diff --git a/java/org/apache/tomcat/util/http/Parameters.java b/java/org/apache/tomcat/util/http/Parameters.java
index d4cc5868b15c..debf968acf0b 100644
--- a/java/org/apache/tomcat/util/http/Parameters.java
+++ b/java/org/apache/tomcat/util/http/Parameters.java
@@ -201,13 +201,13 @@ public void addParameter(String key, String value) throws IllegalStateException
             return;
         }
 
-        parameterCount++;
-        if (limit > -1 && parameterCount > limit) {
+        if (limit > -1 && parameterCount >= limit) {
             // Processing this parameter will push us over the limit. ISE is
             // what Request.parseParts() uses for requests that are too big
             setParseFailedReason(FailReason.TOO_MANY_PARAMETERS);
             throw new IllegalStateException(sm.getString("parameters.maxCountFail", Integer.valueOf(limit)));
         }
+        parameterCount++;
 
         paramHashValues.computeIfAbsent(key, k -> new ArrayList<>(1)).add(value);
     }