diff --git a/package-lock.json b/package-lock.json
index 0cc093e..d799cb4 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -10,6 +10,7 @@
       "license": "MIT",
       "dependencies": {
         "@clack/prompts": "^0.6.1",
+        "@dqbd/tiktoken": "^1.0.2",
         "axios": "^1.3.4",
         "chalk": "^5.2.0",
         "cleye": "^1.3.2",
@@ -83,6 +84,11 @@
         "node": ">=12"
       }
     },
+    "node_modules/@dqbd/tiktoken": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/@dqbd/tiktoken/-/tiktoken-1.0.2.tgz",
+      "integrity": "sha512-AjGTBRWsMoVmVeN55NLyupyM8TNamOUBl6tj5t/leLDVup3CFGO9tVagNL1jf3GyZLkWZSTmYVbPQ/M2LEcNzw=="
+    },
     "node_modules/@esbuild/android-arm": {
       "version": "0.15.18",
       "resolved": "https://registry.npmjs.org/@esbuild/android-arm/-/android-arm-0.15.18.tgz",
diff --git a/package.json b/package.json
index 760b0c1..0ce4593 100644
--- a/package.json
+++ b/package.json
@@ -60,6 +60,7 @@
   },
   "dependencies": {
     "@clack/prompts": "^0.6.1",
+    "@dqbd/tiktoken": "^1.0.2",
     "axios": "^1.3.4",
     "chalk": "^5.2.0",
     "cleye": "^1.3.2",
diff --git a/src/generateCommitMessageFromGitDiff.ts b/src/generateCommitMessageFromGitDiff.ts
index 69100b0..af26956 100644
--- a/src/generateCommitMessageFromGitDiff.ts
+++ b/src/generateCommitMessageFromGitDiff.ts
@@ -6,6 +6,7 @@ import { api } from './api';
 import { getConfig } from './commands/config';
 import { mergeStrings } from './utils/mergeStrings';
 import { i18n, I18nLocals } from './i18n';
+import { tokenCount } from './utils/tokenCount';
 
 const config = getConfig();
 const translation = i18n[(config?.language as I18nLocals) || 'en'];
@@ -13,12 +14,10 @@ const translation = i18n[(config?.language as I18nLocals) || 'en'];
 const INIT_MESSAGES_PROMPT: Array<ChatCompletionRequestMessage> = [
   {
     role: ChatCompletionRequestMessageRoleEnum.System,
-    content: `You are to act as the author of a commit message in git. Your mission is to create clean and comprehensive commit messages in the conventional commit convention. I'll send you an output of 'git diff --staged' command, and you convert it into a commit message. ${
-      config?.emoji
-        ? 'Use Gitmoji convention to preface the commit'
-        : 'Do not preface the commit with anything'
-    }, use the present tense. ${
-      config?.description
+    content: `You are to act as the author of a commit message in git. Your mission is to create clean and comprehensive commit messages in the conventional commit convention. I'll send you an output of 'git diff --staged' command, and you convert it into a commit message. ${config?.emoji
+      ? 'Use Gitmoji convention to preface the commit'
+      : 'Do not preface the commit with anything'
+      }, use the present tense. ${config?.description
         ? 'Add a short description of what commit is about after the commit message. Don\'t start it with "This commit", just describe the changes.'
         : "Don't add any descriptions to the commit, only commit message."
     } Use ${translation.localLanguage} to answer.`
@@ -80,16 +79,16 @@ interface GenerateCommitMessageError {
 }
 
 const INIT_MESSAGES_PROMPT_LENGTH = INIT_MESSAGES_PROMPT.map(
-  (msg) => msg.content
-).join('').length;
+  (msg) => tokenCount(msg.content) + 4
+).reduce((a, b) => a + b, 0);
 
 const MAX_REQ_TOKENS = 3900 - INIT_MESSAGES_PROMPT_LENGTH;
 
 export const generateCommitMessageWithChatCompletion = async (
   diff: string
 ): Promise<string | GenerateCommitMessageError> => {
-  try {
-    if (diff.length >= MAX_REQ_TOKENS) {
+ try {
+    if (tokenCount(diff) >= MAX_REQ_TOKENS) {
       const commitMessagePromises = getCommitMsgsPromisesFromFileDiffs(diff);
 
       const commitMessages = await Promise.all(commitMessagePromises);
@@ -144,7 +143,7 @@ function getCommitMsgsPromisesFromFileDiffs(diff: string) {
   const commitMessagePromises = [];
 
   for (const fileDiff of mergedFilesDiffs) {
-    if (fileDiff.length >= MAX_REQ_TOKENS) {
+    if (tokenCount(fileDiff) >= MAX_REQ_TOKENS) {
       // if file-diff is bigger than gpt context — split fileDiff into lineDiff
       const messagesPromises = getMessagesPromisesByLines(fileDiff, separator);
 
diff --git a/src/utils/mergeStrings.ts b/src/utils/mergeStrings.ts
index 7b55a99..ee35f50 100644
--- a/src/utils/mergeStrings.ts
+++ b/src/utils/mergeStrings.ts
@@ -1,8 +1,9 @@
+import { tokenCount } from './tokenCount'
 export function mergeStrings(arr: string[], maxStringLength: number): string[] {
   const mergedArr: string[] = [];
   let currentItem: string = arr[0];
   for (const item of arr.slice(1)) {
-    if (currentItem.length + item.length <= maxStringLength) {
+    if (tokenCount(currentItem + item) <= maxStringLength) {
       currentItem += item;
     } else {
       mergedArr.push(currentItem);
diff --git a/src/utils/tokenCount.ts b/src/utils/tokenCount.ts
new file mode 100644
index 0000000..84e4f23
--- /dev/null
+++ b/src/utils/tokenCount.ts
@@ -0,0 +1,14 @@
+import { Tiktoken } from "@dqbd/tiktoken/lite"
+import cl100k_base from "@dqbd/tiktoken/encoders/cl100k_base.json" assert{type: "json"}
+
+export function tokenCount(content: string): number {
+    const encoding = new Tiktoken(
+        cl100k_base.bpe_ranks,
+        cl100k_base.special_tokens,
+        cl100k_base.pat_str
+    );
+    const tokens = encoding.encode(content);
+    encoding.free();
+
+    return tokens.length;
+}