diff --git a/CHANGELOG.md b/CHANGELOG.md
index 155fd93aa..e06e03159 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 # 🚀Changelog
 
 -------------------------------------------------------------------------------------------------------------
-# 5.8.40(2025-08-25)
+# 5.8.40(2025-08-26)
 
 ### 🐣新特性
 * 【captcha】      `MathGenerator`四则运算方式支持不生成负数结果（pr#1363@Gitee）
@@ -22,7 +22,8 @@
 * 【extra  】      修复`QLExpressEngine`allowClassSet无效问题（issue#3994@Github）
 * 【core   】      修复`StrBuilder`insert插入计算错误问题（issue#ICTSRZ@Gitee）
 * 【cron   】      修复`CronPatternUtil.nextDateAfter`计算下一个匹配表达式的日期时，计算错误问题（issue#4006@Github）
-* 【cache  】      `ReentrantCache`修改get逻辑key锁改为全局锁，保证安全。（issue#4022@Github）
+* 【cache  】      `ReentrantCache`修改get逻辑key锁改为全局锁，保证安全（issue#4022@Github）
+* 【core   】      修复`NumberWordFormatter`formatSimple输出错误问题（pr#4034@Github）
 
 -------------------------------------------------------------------------------------------------------------
 # 5.8.39(2025-06-20)
diff --git a/hutool-core/src/main/java/cn/hutool/core/convert/NumberWordFormatter.java b/hutool-core/src/main/java/cn/hutool/core/convert/NumberWordFormatter.java
index b2536ea57..5504e8d7e 100644
--- a/hutool-core/src/main/java/cn/hutool/core/convert/NumberWordFormatter.java
+++ b/hutool-core/src/main/java/cn/hutool/core/convert/NumberWordFormatter.java
@@ -66,11 +66,11 @@ public class NumberWordFormatter {
 		}
 
 		double res = value;
-		int index = 0;
+		final int index;
 
 		if (isTwo) {
 			// 当isTwo为true时，只使用k和w单位
-			if (value >= 100000) {
+			if (value >= 10000) {
 				// 使用w单位（除以10000，即10k = 1w）
 				res = value / 10000.0;
 				index = 1; // w在NUMBER_SUFFIX[1]
diff --git a/hutool-core/src/test/java/cn/hutool/core/convert/NumberWordFormatTest.java b/hutool-core/src/test/java/cn/hutool/core/convert/NumberWordFormatTest.java
index 4c563b56a..b0731ca1e 100644
--- a/hutool-core/src/test/java/cn/hutool/core/convert/NumberWordFormatTest.java
+++ b/hutool-core/src/test/java/cn/hutool/core/convert/NumberWordFormatTest.java
@@ -1,8 +1,10 @@
 package cn.hutool.core.convert;
 
-import static org.junit.jupiter.api.Assertions.*;
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 public class NumberWordFormatTest {
 
 	@Test
@@ -43,4 +45,52 @@ public class NumberWordFormatTest {
 		final String s = NumberWordFormatter.formatSimple(1000);
 		assertEquals("1k", s);
 	}
+
+	@Test
+	public void issue4033Test(){
+		String s = NumberWordFormatter.formatSimple(1_000, false);
+		Assertions.assertEquals("1k", s);
+
+		s = NumberWordFormatter.formatSimple(10_000, false);
+		Assertions.assertEquals("10k", s);
+
+		s = NumberWordFormatter.formatSimple(100_000, false);
+		Assertions.assertEquals("100k", s);
+
+		s = NumberWordFormatter.formatSimple(1_000_000, false);
+		Assertions.assertEquals("1m", s);
+
+		s = NumberWordFormatter.formatSimple(10_000_000, false);
+		Assertions.assertEquals("10m", s);
+
+		s = NumberWordFormatter.formatSimple(100_000_000, false);
+		Assertions.assertEquals("100m", s);
+
+		s = NumberWordFormatter.formatSimple(1_000_000_000, false);
+		Assertions.assertEquals("1b", s);
+	}
+
+	@Test
+	public void issue4033Test2(){
+		String s = NumberWordFormatter.formatSimple(1_000, true);
+		Assertions.assertEquals("1k", s);
+
+		s = NumberWordFormatter.formatSimple(10_000, true);
+		Assertions.assertEquals("1w", s);
+
+		s = NumberWordFormatter.formatSimple(100_000, true);
+		Assertions.assertEquals("10w", s);
+
+		s = NumberWordFormatter.formatSimple(1_000_000, true);
+		Assertions.assertEquals("100w", s);
+
+		s = NumberWordFormatter.formatSimple(10_000_000, true);
+		Assertions.assertEquals("1000w", s);
+
+		s = NumberWordFormatter.formatSimple(100_000_000, true);
+		Assertions.assertEquals("10000w", s);
+
+		s = NumberWordFormatter.formatSimple(1_000_000_000, true);
+		Assertions.assertEquals("100000w", s);
+	}
 }