Post

Simon Willison
@simonwillison.net

My notes on the GPT-4.1 series so far - 1m tokens (across all three models) and GPT-4.1-nano being their cheapest model yet are particularly notable simonwillison.net/2025/Apr/14/...

simonwillison.netGPT-4.1: Three new million token input models from OpenAI, including their cheapest model yetOpenAI introduced three new models this morning: GPT-4.1, GPT-4.1 mini and GPT-4.1 nano. These are API-only models right now, not available through the ChatGPT interface (though you can try them …

3 reposts24 likes

Simon Willison
@simonwillison.net

Added this note to my post to help illustrate how absurdly inexpensive these models have got now. I can use GPT-4.1 nano to generate descriptions of 4,000 images for less than a dollar!

Martín Gaitán
@tinnqn.bsky.social

As on the web, a note saying "[*] prices may have changed" seems fair enough. In fact, it could fetch the price list dynamically from the web, so you could update it independently of LLM itself.

Christian Köberl
@derkoe.dev

Thanks for the post! Just tried out 4.1 but like all other models that I've tried it struggles with figuring out the correct line numbers in diffs. For example if you want to review a unified diff, the line numbers often do not match the actual code. Only Claude gets it most of the time.