GPT-4o vs Grok 4.1 Fast
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
GPT-4o
OpenAI · May 2024
The 2024 omni-modal classic with native audio in and out; superseded at the frontier but still everywhere in production.
Grok 4.1 Fast
xAI · Nov 2025
A 2M-token context window for $0.20 per million input tokens — the cheapest long-context frontier offering anywhere.
The verdict
These two models don't yet share verified results on the benchmarks we track, so judge them on specs, pricing and intended use. On price the gap is dramatic: Grok 4.1 Fast works out roughly 16x cheaper per blended million tokens. Grok 4.1 Fast also takes 2M of context versus 128K for GPT-4o.
Specs & pricing
| GPT-4o | Grok 4.1 Fast | |
|---|---|---|
| modhub Index | — | — |
| Input price / 1M | $2.5 | $0.2 |
| Output price / 1M | $10 | $0.5 |
| Context window | 128K | 2M |
| Max output | 16K | — |
| Open weights | no | no |
| Reasoning model | no | yes |
| Multimodal input | text, image, audio | text, image |
| Knowledge cutoff | Oct 2023 | Nov 2025 |
| Released | May 2024 | Nov 2025 |
| Example monthly cost* | $40.00 | $2.75 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, GPT-4o or Grok 4.1 Fast?
- These two models don't yet share verified results on the benchmarks we track, so judge them on specs, pricing and intended use. On price the gap is dramatic: Grok 4.1 Fast works out roughly 16x cheaper per blended million tokens. Grok 4.1 Fast also takes 2M of context versus 128K for GPT-4o.
- Which is cheaper, GPT-4o or Grok 4.1 Fast?
- GPT-4o costs $2.5/$10 per million input/output tokens, while Grok 4.1 Fast costs $0.2/$0.5. For a typical workload of 10M input and 1.5M output tokens per month, that's $40.00 versus $2.75.
- Which model is better for coding, GPT-4o or Grok 4.1 Fast?
- We don't yet track SWE-bench Verified results for both models; check their individual pages for coding-related scores.