diff --git a/options/mzta-options.html b/options/mzta-options.html
index 3ac1fdc2..790aabe0 100644
--- a/options/mzta-options.html
+++ b/options/mzta-options.html
@@ -451,6 +451,7 @@
         <td>
           <label>
             <input type="number" id="max_prompt_length" name="max_prompt_length" class="option-input" />
+            <button type="button" id="reset_max_prompt_length" class="btn_small" style="margin-left:0.5em;">__MSG_reset_default__</button>
             <br>__MSG_prefs_OptionText_max_prompt_length_Info__
           </label>
         </td>
diff --git a/options/mzta-options.js b/options/mzta-options.js
index 0b4d1e28..5ade9216 100644
--- a/options/mzta-options.js
+++ b/options/mzta-options.js
@@ -389,7 +389,12 @@ function resetOpenAICompConfigs(){
   let select_openai_comp_model = document.getElementById('openai_comp_services_shortcut');
   select_openai_comp_model.value = 'custom';
 }
-  
+
+function resetMaxPromptLength(){
+  let maxPromptLength = document.getElementById('max_prompt_length');
+  maxPromptLength.value = prefs_default.max_prompt_length;
+  browser.storage.sync.set({max_prompt_length: prefs_default.max_prompt_length});
+}  
 
 document.addEventListener('DOMContentLoaded', async () => {
   await restoreOptions();
@@ -871,7 +876,8 @@ document.addEventListener('DOMContentLoaded', async () => {
       document.getElementById('openai_comp_use_v1').dispatchEvent(new Event('change', { bubbles: true }));
       document.getElementById('openai_comp_chat_name').dispatchEvent(new Event('change', { bubbles: true }));
     }
-    
   });
 
+  document.getElementById('reset_max_prompt_length').addEventListener('click', resetMaxPromptLength);
+
 }, { once: true });