diff --git a/climbgrades/module.js b/climbgrades/module.js
index 659ea95..ce9a90f 100644
--- a/climbgrades/module.js
+++ b/climbgrades/module.js
@@ -1,68 +1,121 @@
 
+var ClimbGrades = (function() {
+
+  // index UIAA           YDS             French
+  var chart = [
+    [0,  "3",            "5.2",          "1"],
+    [1,  "3/3+",         "5.2",          "1"],
+    [2,  "3+",           "5.3",          "2"],
+    [3,  "3+/4-",        "5.3",          "2"],
+    [4,  "4-",           "5.4",          "3"],
+    [5,  "4-/4",         "5.4",          "3"],
+    [6,  "4",            "5.4",          "3"],
+    [7,  "4/4+",         "5.5",          "4a"],
+    [8,  "4+",           "5.5",          "4a"],
+    [9,  "4+/5-",        "5.5",          "4a"],
+    [10, "5-",           "5.6",          "4b"],
+    [11, "5-/5",         "5.6",          "4b"],
+    [12, "5",            "5.6",          "4b"],
+    [13, "5/5+",         "5.7",          "4c"],
+    [14, "5+",           "5.7",          "4c"],
+    [15, "5+/6-",        "5.8",          "5a"],
+    [16, "6-",           "5.8",          "5a"],
+    [17, "6-/6",         "5.9",          "5b"],
+    [18, "6",            "5.9",          "5b"],
+    [19, "6/6+",         "5.10a",        "5c"],
+    [20, "6+",           "5.10a",        "5c"],
+    [21, "6+/7-",        "5.10b",        "6a"],
+    [22, "7-",           "5.10c",        "6a+"],
+    [23, "7-/7",         "5.10c",        "6a+"],
+    [24, "7",            "5.10d",        "6b"],
+    [25, "7/7+",         "5.10d",        "6b"],
+    [26, "7+",           "5.11a",        "6b+"],
+    [27, "7+/8-",        "5.11b",        "6c"],
+    [28, "8-",           "5.11c",        "6c+"],
+    [29, "8-/8",         "5.11c",        "6c+"],
+    [30, "8",            "5.11d",        "7a"],
+    [31, "8/8+",         "5.12a",        "7a+"],
+    [32, "8+",           "5.12a",        "7a+"],
+    [33, "8+/9-",        "5.12b",        "7b"],
+    [34, "9-",           "5.12c",        "7b+"],
+    [35, "9-/9",         "5.12c",        "7b+"],
+    [36, "9",            "5.12d",        "7c"],
+    [37, "9/9+",         "5.13a",        "7c+"],
+    [38, "9+",           "5.13a",        "7c+"],
+    [39, "9+/10-",       "5.13b",        "8a"],
+    [40, "10-",          "5.13c",        "8a+"],
+    [41, "10-/10",       "5.13c",        "8a+"],
+    [42, "10",           "5.13d",        "8b"],
+    [43, "10/10+",       "5.14a",        "8b+"]
+  ];
+
+
+  var GRADE = {
+    UIAA:   { value: 1, name: "UIAA" },
+    YDS:    { value: 2, name: "YDS" },
+    FRENCH: { value: 3, name: "French" }
+  };
+
+
+  // Use like FromIndex(3, GRADE.UIAA);
+  // returns string "3+/4-"
+  function FromIndex(index, grade) {
+    if (isNaN(parseInt(index)) || index < 0 || index >= chart.length) {
+      throw new TypeError("Invalid index parameter.");
+    }
 
-var uiaa_pattern = /^([3-9])([\+\-])?(?:(?:(\/)[3-9](?:[\+\-])?)?)?$/;
+    if (!grade.hasOwnProperty("name") ||
+        !grade.hasOwnProperty("value")) {
+      throw new TypeError("invalid grade parameter.");
+    }
 
-// Grades
-// 3+
-// 5+/6-
-function GetSportGradeFromUIAA(rating) {
-  return 3.0 * rating - 7.0;
-}
+    if (isNaN(parseInt(grade.value)) || grade.value < 1 || grade.value > 3) {
+      throw new TypeError("grade.value is invalid.");
+    }
 
+    return chart[index][grade.value];
+  }
 
-function GetUIAAFromSportGrade(grade) {
-  return (grade + 7.0) / 3.0;
-}
 
+  function ToIndex(string_value, grade) {
+    if (!grade.hasOwnProperty("value")) {
+      throw new TypeError("invalid grade parameter.");
+    }
 
-function ParseSportGradeFromUIAA(uiaa) {
-  m = uiaa_pattern.exec(uiaa);
-  sport_grade = -1;
-  if (m !== null) {
-    grade = m[1];
-    sport_grade = GetSportGradeFromUIAA(grade);
-    if (m[2] != undefined) {
-      if (m[2] === '+') {
-        sport_grade = sport_grade + 1;
-      } else {
-        sport_grade = sport_grade - 1;
-      }
+    if (isNaN(parseInt(grade.value)) || grade.value < 1 || grade.value > 3) {
+      throw new TypeError("grade.value is invalid.");
     }
 
-    if (m[3] != undefined) {
-      sport_grade = sport_grade + 0.5;
+    var column = grade.value;
+    for (var i = 0; i < chart.length; i++) {
+      if (chart[i][column] === string_value) {
+        return i;
+      }
     }
+    return -1;
   }
 
-  return sport_grade;
+  var module = {
+    GRADE: GRADE,
+    FromIndex: FromIndex,
+    ToIndex: ToIndex
+  };
+
+  return module;
+}());
+
+function ParseSportGradeFromUIAA(uiaa) {
+  var trimmed_uiaa = uiaa.trim();
+  var index = ClimbGrades.ToIndex(trimmed_uiaa, ClimbGrades.GRADE.UIAA);
+  return index;
 }
 
 
 function UIAAFromSportGrade(grade) {
-  rating = GetUIAAFromSportGrade(Math.round(grade));
-  rating_decimal = Math.floor(Math.round(rating,1));
-  slash_symbol = "";
-  if (((rating_decimal + 1) - rating) <= 0.5) {
-    slash_symbol = "/";
-  }
-  follow_symbol = "";
-  delta_from_previous = GetSportGradeFromUIAA(rating_decimal - 1);
-  if (delta_from_previous === 2) {
-    follow_symbol = "-";
-  } else if (delta_from_previous === 4) {
-    follow_symbol = "+";
-  }
-  // recurse if needed
-  follow_on = "";
-  if (slash_symbol === "/") {
-    follow_on = UIAAFromSportGrade(Math.ceil(Math.round(grade)) + 1);
-  }
-
-  str_rating = rating_decimal.toString() + follow_symbol + slash_symbol + follow_on;
-  return str_rating;
+  var uiaa_string = ClimbGrades.FromIndex(grade, ClimbGrades.GRADE.UIAA);
+  return uiaa_string;
 }
 
-
 function print(str) {
   console.log(str);
 }
@@ -90,7 +143,7 @@ function Main() {
     }
   }
 
-  average = accum / climb_count;
+  average = Math.round(accum / climb_count);
   str_average_rating = UIAAFromSportGrade(average);
   print("UIAA average rating -> " + str_average_rating);
   print("Average sport grade -> " + average);