Is Claude or ChatGPT better?

In our September 2026 round, GPT-6 Astra ranked first on 8 of 10 prompts in a blind review, while Claude Fable 5.1 won the EU VAT research question and the water jug puzzle. Both completed every task with zero hallucinations, so the difference is style: GPT-6 Astra answers the brief and stops, Claude explains more and costs about twice as much per answer.

Which is better for coding, Claude or ChatGPT?

Both produced correct, tested code on our two coding prompts. The panel ranked GPT-6 Astra first for leaner solutions, but Claude Fable 5.1 was much faster (19 seconds versus 102 on the slugify task) and its rounding fix needed no extra library, so for day to day coding the gap is small.

Which is cheaper to run, Claude or ChatGPT?

Measured in Krater across the ten prompts, GPT-6 Astra cost $0.23 in total and Claude Fable 5.1 $0.44. Claude was cheaper on the short rewrite prompt and more expensive on everything else.

Can I use Claude and ChatGPT in the same place?

Yes. Krater gives you Claude Fable 5.1, GPT-6 Astra and 400+ other models in one workspace, and the Model Arena lets you send one prompt to several models side by side, which is how this comparison was run.

How was this comparison tested?

All three models (GPT-6 Astra, Claude Fable 5.1 and DeepSeek V4 Pro) received the same ten prompts side by side in the Krater Model Arena on 16 September 2026, with default settings and no system prompt. We recorded time to a complete answer and the model cost per answer, fact checked every claim against a primary source, scored task completion as pass, partial or fail, and then Malte and Vitus Pruser ranked the answers blind, without knowing which model wrote which. The full procedure is on our methodology page.

Will this comparison be updated?

Yes. Flagship comparisons are rerun monthly and whenever a provider ships a new version. The tested month and model versions are shown at the top of the page.

Claude vs ChatGPT: 10 tasks tested side by side (September 2026)

Tested: September 2026 with Claude Fable 5.1 and GPT-6 Astra, by Vitus Pruser.

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