diff --git a/content/zh-cn/cup-calculator.md b/content/zh-cn/cup-calculator.md
index 17cc12e5a9..b654177229 100644
--- a/content/zh-cn/cup-calculator.md
+++ b/content/zh-cn/cup-calculator.md
@@ -21,6 +21,8 @@ description: "罩杯计算器"
     border-image-outset: 0px;
   }
 </style>
+*由于按照国际通用罩杯计算方法修改了计算法，所以计算结果与原来相比可能偏小，不必担心。*
+
 **运算都在您的本地完成，不收集任何数据**
 
 1. 请准备一根软尺并面对镜子，看得到胸部
@@ -30,6 +32,14 @@ description: "罩杯计算器"
 1. 请俯身 45 度：<input type="text" id="val4"/> cm
 1. 请鞠躬 90 度：<input type="text" id="val5"/> cm
 
+国际通用罩杯计算方法：
+
+- 下胸围 + 11 cm + n × 2 cm = 胸围
+
+- 罩杯 n =（胸围 − 下胸围 − 11） / 2
+
+数字 n 代表罩杯 (A=1、B=2、C=3依此类推)。例如，胸围和下胸围差为15 cm (n=2)表示B罩杯。
+
 <button onclick="cup()" type="submit">提交</button>
 
 <p id="result"></p>
@@ -41,38 +51,39 @@ description: "罩杯计算器"
     var val3 = Number(window.document.getElementById("val3").value) || NaN;
     var val4 = Number(window.document.getElementById("val4").value) || NaN;
     var val5 = Number(window.document.getElementById("val5").value) || NaN;
-    var xia = (val1 + val2 )/2;
-    var cup = (val3 + val4 + val5)/3 - xia;
+    var under = (val1 + val2 )/2;
+    var upper = (val3 + val4 + val5)/3;
+    var cup = ( upper - under - 11 ) / 2;
 
     if (isNaN(cup)) {
       window.document.getElementById("result").innerHTML = "数值错误，再检查检查吧";
       return;
-    } else if (cup<5){
+    } else if (cup<=0){
       window.document.getElementById("result").innerHTML = "小妹妹你还不需要穿内衣哦";
       return;
-    } else if (cup<=7.5){
+    } else if (cup<1){
       cup = "AA，买少女小背心去吧";
-    } else if (cup<=10){
+    } else if (cup<=2){
       cup = "A";
-    } else if (cup<=12.5){
+    } else if (cup<3){
       cup = "B";
-    } else if (cup<=15){
+    } else if (cup<4){
       cup = "C";
-    } else if (cup<=17.5){
+    } else if (cup<5){
       cup = "D";
-    } else if (cup<=20){
+    } else if (cup<6){
       cup = "E";
     }else{
       window.document.getElementById("result").innerHTML = "你胸大你说了算（罩杯超出 MtF.wiki 预设）";
       return;
     }
-    if (isNaN(xia)) {
+    if (isNaN(under)) {
       window.document.getElementById("result").innerHTML = "数值错误，再检查检查吧";
       return;
     } else{
-      xia = Math.ceil(xia/5)*5;
+      under = Math.ceil(under/5)*5;
     }
-      window.document.getElementById("result").innerHTML = xia + cup;
+      window.document.getElementById("result").innerHTML = under + cup;
     return;
   }
 </script>
diff --git a/content/zh-hant/cup-calculator.md b/content/zh-hant/cup-calculator.md
index fd27aa0bbf..9096286349 100644
--- a/content/zh-hant/cup-calculator.md
+++ b/content/zh-hant/cup-calculator.md
@@ -21,6 +21,8 @@ description: "胸圍計算"
     border-image-outset: 0px;
   }
 </style>
+*由於按照國際通用罩杯計算方法修改了計算法，所以計算結果與原來相比可能偏小，不必擔心。*
+
 **計算會在你的電腦上完成，不會向伺服器回傳任何資料**
 
 1. 請準備一條量身軟尺，面向鏡子，要能看到胸部
@@ -30,6 +32,14 @@ description: "胸圍計算"
 1. 請俯身 45 度：<input type="text" id="val4"/> cm
 1. 請鞠躬 90 度：<input type="text" id="val5"/> cm
 
+國際通用胸罩尺碼計算方法：
+
+- 下胸圍 + 11 cm + n × 2 cm = 胸圍
+
+- 罩杯 n =（胸圍 − 下胸圍 − 11） / 2
+
+數字 n 代表罩杯 (A=1、B=2、C=3依此類推)。例如，胸圍和下胸圍差為15 cm (n=2)表示B罩杯。
+
 <button onclick="cup()" type="submit">計算</button>
 
 <p id="result"></p>
@@ -41,38 +51,39 @@ description: "胸圍計算"
     var val3 = Number(window.document.getElementById("val3").value) || NaN;
     var val4 = Number(window.document.getElementById("val4").value) || NaN;
     var val5 = Number(window.document.getElementById("val5").value) || NaN;
-    var xia = (val1 + val2 )/2;
-    var cup = (val3 + val4 + val5)/3 - xia;
+    var under = (val1 + val2 )/2;
+    var upper = (val3 + val4 + val5)/3;
+    var cup = ( upper - under - 11 ) / 2;
 
     if (isNaN(cup)) {
       window.document.getElementById("result").innerHTML = "輸入有誤，再檢查一下吧";
       return;
-    } else if (cup<5){
+    } else if (cup<=0){
       window.document.getElementById("result").innerHTML = "小妹妹妳還不需要穿內衣唷";
       return;
-    } else if (cup<=7.5){
+    } else if (cup<1){
       cup = "AA，購買少女內衣";
-    } else if (cup<=10){
+    } else if (cup<2){
       cup = "A";
-    } else if (cup<=12.5){
+    } else if (cup<3){
       cup = "B";
-    } else if (cup<=15){
+    } else if (cup<4){
       cup = "C";
-    } else if (cup<=17.5){
+    } else if (cup<5){
       cup = "D";
-    } else if (cup<=20){
+    } else if (cup<6){
       cup = "E";
     }else{
       window.document.getElementById("result").innerHTML = "妳胸大妳說了算（罩杯超出 MtF.wiki 預設）";
       return;
     }
-    if (isNaN(xia)) {
+    if (isNaN(under)) {
       window.document.getElementById("result").innerHTML = "輸入有誤，再檢查一下吧";
       return;
     } else{
-      xia = Math.ceil(xia/5)*5;
+      under = Math.ceil(under/5)*5;
     }
-      window.document.getElementById("result").innerHTML = xia + cup;
+      window.document.getElementById("result").innerHTML = under + cup;
     return;
   }
 </script>