diff --git a/src/main/java/sixgaezzang/sidepeek/projects/util/validation/ProjectValidator.java b/src/main/java/sixgaezzang/sidepeek/projects/util/validation/ProjectValidator.java
index cd36df20..1ddd33c6 100644
--- a/src/main/java/sixgaezzang/sidepeek/projects/util/validation/ProjectValidator.java
+++ b/src/main/java/sixgaezzang/sidepeek/projects/util/validation/ProjectValidator.java
@@ -92,7 +92,7 @@ public static void validateDuration(YearMonth startDate, YearMonth endDate) {
         }
 
         if (Objects.nonNull(startDate) && Objects.nonNull(endDate)) {
-            if (startDate.compareTo(endDate) >= 0) {
+            if (startDate.compareTo(endDate) > 0) {
                 throw new IllegalArgumentException(DURATION_IS_REVERSED);
             }
             return;