Compare AI models
| API pricingUSD per 1M tokens · lower wins | ||
Input priceWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it. | $0.30 | — |
Output priceWhat you pay for the text the model writes back. It is normally the dearer half: producing an answer costs more than reading one. | $2.50 | — |
Cached input priceA reduced rate for text you send over and over. If every request starts with the same instructions or the same document, the provider keeps a copy ready and charges less to read it again. | $0.03 | — |
Cheapest inputLowest input rate across every provider on OpenRouter, the lab included. The cheapest endpoint may run a quantised build or a shorter context — see "Available from" on the model page. | $0.15Google AI Studio | — |
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input. | $1.25Google AI Studio | — |
| $185Google list price | — | |
| Benchmarks | ||
BullshitBench v2Nonsense detection — Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 19% | 39% |
| Overview | ||
| Company | OpenAI | |
| Release date | Apr 17 2025 | Sep 15 2025 |
| Access | Closed | Closed |
| Model details | View model | View model |
Other comparisons
Gemini 2.5 FlashvsClaude Haiku 5.5GPT-5-CodexvsClaude Haiku 5.5Gemini 2.5 FlashvsMuse WonderGPT-5-CodexvsMuse WonderGemini 2.5 FlashvsGrok 4.7GPT-5-CodexvsGrok 4.7Gemini 2.5 FlashvsDeepSeek-V4.1-FlashGPT-5-CodexvsDeepSeek-V4.1-FlashGemini 2.5 FlashvsMistral Large 4GPT-5-CodexvsMistral Large 4Gemini 2.5 FlashvsKimi K3GPT-5-CodexvsKimi K3Frequently asked questions
GPT-5-Codex leads Gemini 2.5 Flash on 1 of the 1 benchmark they both report (BullshitBench v2). Only Gemini 2.5 Flash has a verified first-party API price: $0.30 per million input tokens and $2.50 per million output tokens. No pay-as-you-go API rate is tracked for GPT-5-Codex. Gemini 2.5 Flash shipped 151 days before GPT-5-Codex, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
On BullshitBench v2, GPT-5-Codex leads at 39% vs Gemini 2.5 Flash at 19%.