ChatGPT Token Counter by Lakeside Apps

See how long your prompt and your whole conversation really are before you send. A small counter above the input box updates while you type and shows how full the context window of your plan is. Counting happens on your device with the o200k_base encoding, so the numbers match OpenAI's tiktoken library instead of a word-count guess. The free version has no limit. Pro costs $5.99 once, no subscription.

WHAT IT DOES
You see the length of your draft and of the full conversation, split into your messages and the replies. Pick your plan and mode in the toolbar popup and a bar shows the share of the context window already used and what is left. A text box in the popup counts anything you paste, on any site.

HOW IT WORKS
1. Open ChatGPT and start typing; the counter appears above the input box.
2. Choose your plan and Instant or Reasoning mode in the popup.
3. Click the counter for details: your draft, both sides of the conversation and the space left.

FREE
• Live count of your draft while you type, without a limit.
• Conversation total with a context bar for your plan.
• A text box in the popup that counts any pasted text.
• The on-page display can be hidden with one switch.

PRO ($5.99, LIFETIME)
• API cost estimate for the next message, from published list prices for 15 models.
• Cost of the whole conversation as API calls, turn by turn, input and output.
• The same live count on five more AI chat sites, each switched on separately and only after you allow that site.

ABOUT THE NUMBERS
Window sizes come from the official pricing page and API prices from the official API pricing page, both checked on 23 October 2026 and linked in the popup. All results are estimates: hidden system instructions, memory, uploaded files and images are not visible on the page and are not counted, and newer models may split text slightly differently.

PRIVACY
Everything runs in your browser. The extension reads the tab you have open and sends no text anywhere. The only data sent is the email you enter to buy or restore Pro, which is checked against the payment.

Not affiliated with or endorsed by OpenAI. ChatGPT is a trademark of OpenAI.
Questions: scanlystudio.support@proton.me