ChatGPT vs Claude: why not both?

The short answer

You do not have to choose. OpenAI and Anthropic both ship new models every few months, so whichever one is ahead today may not be next quarter. Keep both open on one screen and you always have the other one a click away.

What you get with each

ChatGPT is OpenAI's assistant. Through the API you reach the same family: GPT-6.1 Sol, GPT-6 Astra, GPT-6.1 Terra, GPT-6 Luna and GPT-6 Sol.

Claude is Anthropic's. Through the API: Claude Opus 5.5, Claude Sonnet 5.5, Claude Fable 5.1 and Claude Haiku 5.5.

Where they differ most

The clearest differences are in the tools. In MultiScreenAI, Claude can search the web and run code that returns real files, such as a spreadsheet or a zip. On the OpenAI side, GPT Image models draw pictures. For plain writing and reasoning the gap moves with every release, which is one more reason to keep both open.

Using both at once

• In Multi-screen mode each panel is its own chat: one with ChatGPT, one with Claude, or more.
• Talk to each one separately, or send one message to both from the bar at the bottom.
• Send an answer from one panel to the other to have it checked.
• Merge both answers into one with the model you trust most.

Up to six panels run at once, so add Grok, DeepSeek or a free model next to them. More in Multi-screen mode and Test mode.

What each can do in MultiScreenAI

• ChatGPT reads PDFs natively and has GPT Image models that answer with pictures.
• Claude can search the web with sources, run code that hands you real downloadable files, and reads PDFs natively.

Switch the tools on in a panel's header: Web search, code and real files.

What it costs

OpenAI and Anthropic both bill the API per token, with no monthly fee and no permanent free tier. You pay each company directly at its own rate; MultiScreenAI adds nothing on top, and Pro is free with a follow on X. Want to start at zero? See every free API key.

When you do need to pick one: test them

1. Switch to Test mode. One prompt goes to every panel.
2. Turn on Blind test so the names are hidden as Model A and Model B.
3. Each answer is timed: time to first word, total time and words per second.
4. Star the better answer, then reveal who wrote it. Try five or six kinds of task before you decide.

Prompts worth testing

• A real email you need to write, with the background pasted in.
• A bug from your own code, with the full error message.
• A long PDF you need summarised, plus three questions about it.
• An instruction with several rules, such as "under 120 words, no jargon, end with a question".
• A question you already know the answer to, to catch confident mistakes.