diff --git a/aider/coders/base_coder.py b/aider/coders/base_coder.py
index 57de58f45..1b419a110 100755
--- a/aider/coders/base_coder.py
+++ b/aider/coders/base_coder.py
@@ -420,15 +420,9 @@ class Coder:
         prompt = prompt.format(fence=self.fence)
         return prompt
 
-    def send_new_user_message(self, inp):
+    def format_messages(self):
         self.choose_fence()
-
-        self.cur_messages += [
-            dict(role="user", content=inp),
-        ]
-
         main_sys = self.gpt_prompts.main_system
-        # if self.main_model.max_context_tokens > 4 * 1024:
         main_sys += "\n" + self.fmt_system_reminder()
 
         messages = [
@@ -440,6 +434,15 @@ class Coder:
         messages += self.get_files_messages()
         messages += self.cur_messages
 
+        return messages
+
+    def send_new_user_message(self, inp):
+        self.cur_messages += [
+            dict(role="user", content=inp),
+        ]
+
+        messages = self.format_messages()
+
         if self.verbose:
             utils.show_messages(messages, functions=self.functions)
 
diff --git a/aider/commands.py b/aider/commands.py
index c4e9f4b15..2027d64d6 100644
--- a/aider/commands.py
+++ b/aider/commands.py
@@ -1,4 +1,3 @@
-import json
 import re
 import subprocess
 import sys
@@ -109,14 +108,13 @@ class Commands:
             dict(role="system", content=self.coder.gpt_prompts.main_system),
             dict(role="system", content=self.coder.gpt_prompts.system_reminder),
         ]
-        tokens = self.coder.main_model.token_count(json.dumps(msgs))
+        tokens = self.coder.main_model.token_count(msgs)
         res.append((tokens, "system messages", ""))
 
         # chat history
         msgs = self.coder.done_messages + self.coder.cur_messages
         if msgs:
             msgs = [dict(role="dummy", content=msg) for msg in msgs]
-            msgs = json.dumps(msgs)
             tokens = self.coder.main_model.token_count(msgs)
             res.append((tokens, "chat history", "use /clear to clear"))
 
diff --git a/aider/models/model.py b/aider/models/model.py
index 904ec8af0..7522c97e0 100644
--- a/aider/models/model.py
+++ b/aider/models/model.py
@@ -1,3 +1,5 @@
+import json
+
 import openai
 
 
@@ -37,3 +39,14 @@ class Model:
     @staticmethod
     def commit_message_models():
         return [Model.create("gpt-3.5-turbo"), Model.create("gpt-3.5-turbo-16k")]
+
+    def token_count(self, messages):
+        if not self.tokenizer:
+            return
+
+        if type(messages) is str:
+            msgs = messages
+        else:
+            msgs = json.dumps(messages)
+
+        return len(self.tokenizer.encode(msgs))