diff --git a/backend/dao/user.js b/backend/dao/user.js
index 3ee867726..7e8a78513 100644
--- a/backend/dao/user.js
+++ b/backend/dao/user.js
@@ -167,19 +167,7 @@ class UsersDAO {
   }
 
   static async checkIfPb(uid, user, result) {
-    const {
-      mode,
-      mode2,
-      acc,
-      consistency,
-      difficulty,
-      lazyMode,
-      language,
-      punctuation,
-      rawWpm,
-      wpm,
-      funbox,
-    } = result;
+    const { mode, funbox } = result;
 
     if (funbox !== "none" && funbox !== "plus_one" && funbox !== "plus_two") {
       return false;
@@ -192,20 +180,7 @@ class UsersDAO {
     let lbpb = user.lbPersonalBests;
     if (!lbpb) lbpb = {};
 
-    let pb = checkAndUpdatePb(
-      user.personalBests,
-      lbpb,
-      mode,
-      mode2,
-      acc,
-      consistency,
-      difficulty,
-      lazyMode,
-      language,
-      punctuation,
-      rawWpm,
-      wpm
-    );
+    let pb = checkAndUpdatePb(user.personalBests, lbpb, result);
 
     if (pb.isPb) {
       await db
@@ -227,20 +202,7 @@ class UsersDAO {
       return [];
     }
 
-    const {
-      mode,
-      mode2,
-      acc,
-      consistency,
-      difficulty,
-      lazyMode,
-      language,
-      punctuation,
-      rawWpm,
-      wpm,
-      tags,
-      funbox,
-    } = result;
+    const { mode, tags, funbox } = result;
 
     if (funbox !== "none" && funbox !== "plus_one" && funbox !== "plus_two") {
       return [];
@@ -262,20 +224,7 @@ class UsersDAO {
     let ret = [];
 
     tagsToCheck.forEach(async (tag) => {
-      let tagpb = checkAndUpdatePb(
-        tag.personalBests,
-        undefined,
-        mode,
-        mode2,
-        acc,
-        consistency,
-        difficulty,
-        lazyMode,
-        language,
-        punctuation,
-        rawWpm,
-        wpm
-      );
+      let tagpb = checkAndUpdatePb(tag.personalBests, undefined, result);
       if (tagpb.isPb) {
         ret.push(tag._id);
         await db
diff --git a/backend/utils/pb.js b/backend/utils/pb.js
deleted file mode 100644
index b54bc73d1..000000000
--- a/backend/utils/pb.js
+++ /dev/null
@@ -1,148 +0,0 @@
-/*
-
-
-obj structure
-
-time: {
-  10: [ - this is a list because there can be
-    different personal bests for different difficulties, languages and punctuation
-    {
-      acc,
-      consistency,
-      difficulty,
-      language,
-      punctuation,
-      raw,
-      timestamp,
-      wpm
-    }
-  ]
-},
-words: {
-  10: [
-    {}
-  ]
-},
-zen: {
-  zen: [
-    {}
-  ]
-},
-custom: {
-  custom: {
-    []
-  }
-}
-
-
-
-
-
-*/
-
-export function checkAndUpdatePb(
-  obj,
-  lbObj,
-  mode,
-  mode2,
-  acc,
-  consistency,
-  difficulty,
-  lazyMode = false,
-  language,
-  punctuation,
-  raw,
-  wpm
-) {
-  //verify structure first
-  if (obj === undefined) obj = {};
-  if (obj[mode] === undefined) obj[mode] = {};
-  if (obj[mode][mode2] === undefined) obj[mode][mode2] = [];
-
-  let isPb = false;
-  let found = false;
-  //find a pb
-  obj[mode][mode2].forEach((pb) => {
-    //check if we should compare first
-    if (
-      (pb.lazyMode === lazyMode ||
-        (pb.lazyMode === undefined && lazyMode === false)) &&
-      pb.difficulty === difficulty &&
-      pb.language === language &&
-      pb.punctuation === punctuation
-    ) {
-      found = true;
-      //compare
-      if (pb.wpm < wpm) {
-        //update
-        isPb = true;
-        pb.acc = acc;
-        pb.consistency = consistency;
-        pb.difficulty = difficulty;
-        pb.language = language;
-        pb.punctuation = punctuation;
-        pb.lazyMode = lazyMode;
-        pb.raw = raw;
-        pb.wpm = wpm;
-        pb.timestamp = Date.now();
-      }
-    }
-  });
-  //if not found push a new one
-  if (!found) {
-    isPb = true;
-    obj[mode][mode2].push({
-      acc,
-      consistency,
-      difficulty,
-      lazyMode,
-      language,
-      punctuation,
-      raw,
-      wpm,
-      timestamp: Date.now(),
-    });
-  }
-
-  if (
-    lbObj &&
-    mode === "time" &&
-    (mode2 == "15" || mode2 == "60") &&
-    !lazyMode
-  ) {
-    //updating lbpersonalbests object
-    //verify structure first
-    if (lbObj[mode] === undefined) lbObj[mode] = {};
-    if (lbObj[mode][mode2] === undefined || Array.isArray(lbObj[mode][mode2]))
-      lbObj[mode][mode2] = {};
-
-    let bestForEveryLanguage = {};
-    if (obj?.[mode]?.[mode2]) {
-      obj[mode][mode2].forEach((pb) => {
-        if (!bestForEveryLanguage[pb.language]) {
-          bestForEveryLanguage[pb.language] = pb;
-        } else {
-          if (bestForEveryLanguage[pb.language].wpm < pb.wpm) {
-            bestForEveryLanguage[pb.language] = pb;
-          }
-        }
-      });
-      Object.keys(bestForEveryLanguage).forEach((key) => {
-        if (lbObj[mode][mode2][key] === undefined) {
-          lbObj[mode][mode2][key] = bestForEveryLanguage[key];
-        } else {
-          if (lbObj[mode][mode2][key].wpm < bestForEveryLanguage[key].wpm) {
-            lbObj[mode][mode2][key] = bestForEveryLanguage[key];
-          }
-        }
-      });
-      bestForEveryLanguage = {};
-    }
-  }
-
-  return {
-    isPb,
-    obj,
-    lbObj,
-  };
-}
diff --git a/backend/utils/pb.ts b/backend/utils/pb.ts
new file mode 100644
index 000000000..0ff3af98e
--- /dev/null
+++ b/backend/utils/pb.ts
@@ -0,0 +1,146 @@
+import _ from "lodash";
+
+interface CheckAndUpdatePbResult {
+  isPb: boolean;
+  obj: object;
+  lbObj: object;
+}
+
+type Result = MonkeyTypes.Result<MonkeyTypes.Mode>;
+
+export function checkAndUpdatePb(
+  userPersonalBests: MonkeyTypes.User["personalBests"],
+  lbPersonalBests: MonkeyTypes.User["lbPersonalBests"],
+  result: Result
+): CheckAndUpdatePbResult {
+  const { mode, mode2 } = result;
+
+  const userPb = userPersonalBests ?? {};
+  userPb[mode] = userPb[mode] ?? {};
+  userPb[mode][mode2] = userPb[mode][mode2] ?? [];
+
+  const personalBestMatch: MonkeyTypes.PersonalBest = userPb[mode][mode2].find(
+    (pb: MonkeyTypes.PersonalBest) => {
+      return matchesPersonalBest(result, pb);
+    }
+  );
+
+  let isPb = true;
+
+  if (personalBestMatch) {
+    const didUpdate = updatePersonalBest(personalBestMatch, result);
+    isPb = didUpdate;
+  } else {
+    userPb[mode][mode2].push(buildPersonalBest(result));
+  }
+
+  updateLeaderboardPersonalBests(userPb, lbPersonalBests, result);
+
+  return {
+    isPb,
+    obj: userPb,
+    lbObj: lbPersonalBests,
+  };
+}
+
+function matchesPersonalBest(
+  result: Result,
+  personalBest: MonkeyTypes.PersonalBest
+): boolean {
+  const sameLazyMode =
+    result.lazyMode === personalBest.lazyMode ||
+    (!result.lazyMode && !personalBest.lazyMode);
+  const samePunctuation = result.punctuation === personalBest.punctuation;
+  const sameDifficulty = result.difficulty === personalBest.difficulty;
+  const sameLanguage = result.language === personalBest.language;
+
+  return sameLazyMode && samePunctuation && sameDifficulty && sameLanguage;
+}
+
+function updatePersonalBest(
+  personalBest: MonkeyTypes.PersonalBest,
+  result: Result
+): boolean {
+  if (personalBest.wpm > result.wpm) {
+    return false;
+  }
+
+  personalBest.acc = result.acc;
+  personalBest.consistency = result.consistency;
+  personalBest.difficulty = result.difficulty;
+  personalBest.language = result.language;
+  personalBest.punctuation = result.punctuation;
+  personalBest.lazyMode = result.lazyMode;
+  personalBest.raw = result.rawWpm;
+  personalBest.wpm = result.wpm;
+  personalBest.timestamp = Date.now();
+
+  return true;
+}
+
+function buildPersonalBest(result: Result): MonkeyTypes.PersonalBest {
+  return {
+    acc: result.acc,
+    consistency: result.consistency,
+    difficulty: result.difficulty,
+    lazyMode: result.lazyMode,
+    language: result.language,
+    punctuation: result.punctuation,
+    raw: result.rawWpm,
+    wpm: result.wpm,
+    timestamp: Date.now(),
+  };
+}
+
+function updateLeaderboardPersonalBests(
+  userPersonalBests: MonkeyTypes.User["personalBests"],
+  lbPersonalBests: MonkeyTypes.User["lbPersonalBests"],
+  result: Result
+): void {
+  if (!shouldUpdateLeaderboardPersonalBests(lbPersonalBests, result)) {
+    return;
+  }
+
+  const { mode, mode2 } = result;
+
+  lbPersonalBests[mode] = lbPersonalBests[mode] ?? {};
+  const lbMode2 = lbPersonalBests[mode][mode2];
+  if (!lbMode2 || Array.isArray(lbMode2)) {
+    lbPersonalBests[mode][mode2] = {};
+  }
+
+  const bestForEveryLanguage = {};
+
+  userPersonalBests[mode][mode2].forEach((pb: MonkeyTypes.PersonalBest) => {
+    const language = pb.language;
+    if (
+      !bestForEveryLanguage[language] ||
+      bestForEveryLanguage[language].wpm < pb.wpm
+    ) {
+      bestForEveryLanguage[language] = pb;
+    }
+  });
+
+  _.each(
+    bestForEveryLanguage,
+    (pb: MonkeyTypes.PersonalBest, language: string) => {
+      const languageDoesNotExist = !lbPersonalBests[mode][mode2][language];
+
+      if (
+        languageDoesNotExist ||
+        lbPersonalBests[mode][mode2][language].wpm < pb.wpm
+      ) {
+        lbPersonalBests[mode][mode2][language] = pb;
+      }
+    }
+  );
+}
+
+function shouldUpdateLeaderboardPersonalBests(
+  lbPersonalBests: MonkeyTypes.User["lbPersonalBests"],
+  result: Result
+): boolean {
+  const isValidTimeMode =
+    result.mode === "time" && (result.mode2 === "15" || result.mode2 === "60");
+  return lbPersonalBests && isValidTimeMode && !result.lazyMode;
+}