diff --git a/src/app.tsx b/src/app.tsx
index 47c3154..462345c 100644
--- a/src/app.tsx
+++ b/src/app.tsx
@@ -4,7 +4,7 @@ import "./global.css";
 import { calculate_token_length, Message } from "./chatgpt";
 import getDefaultParams from "./getDefaultParam";
 import ChatBOX from "./chatbox";
-import { options } from "./settings";
+import models from "./models";
 
 import CHATGPT_API_WEB_VERSION from "./CHATGPT_API_WEB_VERSION";
 
@@ -26,6 +26,7 @@ export interface ChatStore {
   streamMode: boolean;
   model: string;
   responseModelName: string;
+  cost: number;
 }
 
 const _defaultAPIEndpoint = "https://api.openai.com/v1/chat/completions";
@@ -43,12 +44,13 @@ const newChatStore = (
     postBeginIndex: 0,
     tokenMargin: 1024,
     totalTokens: 0,
-    maxTokens: options[getDefaultParams("model", model)],
+    maxTokens: models[getDefaultParams("model", model)].maxToken,
     apiKey: getDefaultParams("key", apiKey),
     apiEndpoint: getDefaultParams("api", apiEndpoint),
     streamMode: getDefaultParams("mode", streamMode),
     model: getDefaultParams("model", model),
     responseModelName: "",
+    cost: 0,
   };
 };
 
@@ -99,6 +101,7 @@ export function App() {
       if (message.token === undefined)
         message.token = calculate_token_length(message.content);
     }
+    if (ret.cost === undefined) ret.cost = 0;
     return ret;
   };
 
diff --git a/src/chatbox.tsx b/src/chatbox.tsx
index fa52423..585b9a0 100644
--- a/src/chatbox.tsx
+++ b/src/chatbox.tsx
@@ -7,6 +7,7 @@ import ChatGPT, {
   FetchResponse,
 } from "./chatgpt";
 import Message from "./message";
+import models from "./models";
 import Settings from "./settings";
 
 export default function ChatBOX(props: {
@@ -102,6 +103,13 @@ export default function ChatBOX(props: {
     chatStore.streamMode = false;
     const data = (await response.json()) as FetchResponse;
     chatStore.responseModelName = data.model ?? "";
+    if (data.model) {
+      chatStore.cost +=
+        (data.usage.prompt_tokens ?? 0) * models[data.model].price.prompt;
+      chatStore.cost +=
+        (data.usage.completion_tokens ?? 0) *
+        models[data.model].price.completion;
+    }
     const content = client.processFetchResponse(data);
     chatStore.history.push({
       role: "assistant",
@@ -239,9 +247,10 @@ export default function ChatBOX(props: {
           </span>{" "}
           <span>{chatStore.model}</span>{" "}
           <span>
-            Messages: {chatStore.history.filter(({ hide }) => !hide).length}
+            Msg: {chatStore.history.filter(({ hide }) => !hide).length}
           </span>{" "}
-          <span>Cut: {chatStore.postBeginIndex}</span>
+          <span>Cut: {chatStore.postBeginIndex}</span>{" "}
+          <span className="underline">${chatStore.cost.toFixed(4)}</span>
         </div>
       </p>
       <div className="grow overflow-scroll">
diff --git a/src/models.ts b/src/models.ts
new file mode 100644
index 0000000..ada18ff
--- /dev/null
+++ b/src/models.ts
@@ -0,0 +1,36 @@
+interface Model {
+  maxToken: number;
+  price: {
+    prompt: number;
+    completion: number;
+  };
+}
+
+const models: Record<string, Model> = {
+  "gpt-3.5-turbo": {
+    maxToken: 4096,
+    price: { prompt: 0.002 / 1000, completion: 0.002 / 1000 },
+  },
+  "gpt-3.5-turbo-0301": {
+    maxToken: 4096,
+    price: { prompt: 0.002 / 1000, completion: 0.002 / 1000 },
+  },
+  "gpt-4": {
+    maxToken: 8192,
+    price: { prompt: 0.03 / 1000, completion: 0.06 / 1000 },
+  },
+  "gpt-4-0314": {
+    maxToken: 8192,
+    price: { prompt: 0.03 / 1000, completion: 0.06 / 1000 },
+  },
+  "gpt-4-32k": {
+    maxToken: 8192,
+    price: { prompt: 0.03 / 1000, completion: 0.06 / 1000 },
+  },
+  "gpt-4-32k-0314": {
+    maxToken: 8192,
+    price: { prompt: 0.06 / 1000, completion: 0.12 / 1000 },
+  },
+};
+
+export default models;
diff --git a/src/settings.tsx b/src/settings.tsx
index 4ef9b80..ed23bc9 100644
--- a/src/settings.tsx
+++ b/src/settings.tsx
@@ -1,6 +1,7 @@
 import { createRef } from "preact";
 import { StateUpdater } from "preact/hooks";
 import { ChatStore } from "./app";
+import models from "./models";
 
 const Help = (props: { children: any; help: string }) => {
   return (
@@ -18,16 +19,6 @@ const Help = (props: { children: any; help: string }) => {
   );
 };
 
-// model and their max token
-export const options: Record<string, number> = {
-  "gpt-3.5-turbo": 4096,
-  "gpt-3.5-turbo-0301": 4096,
-  "gpt-4": 8192,
-  "gpt-4-0314": 8192,
-  "gpt-4-32k": 32768,
-  "gpt-4-32k-0314": 32768,
-};
-
 const SelectModel = (props: {
   chatStore: ChatStore;
   setChatStore: (cs: ChatStore) => void;
@@ -42,11 +33,11 @@ const SelectModel = (props: {
         onChange={(event: any) => {
           const model = event.target.value as string;
           props.chatStore.model = model;
-          props.chatStore.maxTokens = options[model];
+          props.chatStore.maxTokens = models[model].maxToken;
           props.setChatStore({ ...props.chatStore });
         }}
       >
-        {Object.keys(options).map((opt) => (
+        {Object.keys(models).map((opt) => (
           <option value={opt}>{opt}</option>
         ))}
       </select>
@@ -149,6 +140,9 @@ export default (props: {
       <div className="m-2 p-2 bg-white rounded-lg h-fit">
         <h3 className="text-xl">Settings</h3>
         <hr />
+        <p className="m-2 p-2">
+          Total cost in this section ${props.chatStore.cost.toFixed(4)}
+        </p>
         <div className="box">
           <Input
             field="systemMessageContent"
@@ -269,6 +263,10 @@ export default (props: {
               }}
             />
           </p>
+          <p className="text-center m-2 p-2">
+            chatgpt-api-web ChatStore Version{" "}
+            {props.chatStore.chatgpt_api_web_version}
+          </p>
         </div>
         <hr />
         <div className="flex justify-between">