ChatGPT alternatives
ChatGPT is OpenAI's chat product; under the hood it runs OpenAI's GPT models, so alternatives are computed against OpenAI's current flagship; The closest alternative to ChatGPT is Claude Fable 5 — comparable intelligence (59.9 vs 58.9); for a cheaper option, Kimi K3 runs $3.00/M vs $5.00/M; and the best open-weight substitute is GLM 5.2.
Closest match
Cheaper alternatives
Smarter alternatives
Open-source alternatives
Frequently asked
What is the best alternative to ChatGPT?
Claude Fable 5 is the closest alternative to ChatGPT, with an Intelligence Index of 59.9 (ChatGPT scores 58.9) at $10.00 per million input tokens.
Is there a cheaper alternative to ChatGPT?
Yes — Kimi K3 costs $3.00 per million input tokens versus $5.00 for ChatGPT, while staying within ~8 points of its Intelligence Index.
Is there an open-source alternative to ChatGPT?
GLM 5.2 is the strongest open-weight alternative to ChatGPT — downloadable from Hugging Face and self-hostable, scoring 51.1 on intelligence.