GPT-4.1 vs GPT-5.1
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
GPT-4.1
OpenAI · Apr 2025
A non-reasoning workhorse with a 1M-token context window, still popular for predictable-latency production APIs.
GPT-5.1
59.6OpenAI · Nov 2025
A November 2025 update to GPT-5 with adaptive reasoning that spends thinking tokens only when a task needs them.
The verdict
GPT-5.1 wins 2 of the 2 benchmarks these models share, against 0 for GPT-4.1. GPT-5.1 is about 1.0x cheaper per blended million tokens (3:1 input:output mix). GPT-4.1 also takes 1M of context versus 400K for GPT-5.1.
Benchmark head-to-head 0–2
Specs & pricing
| GPT-4.1 | GPT-5.1 | |
|---|---|---|
| modhub Index | — | 59.6 |
| Input price / 1M | $2 | $1.25 |
| Output price / 1M | $8 | $10 |
| Context window | 1M | 400K |
| Max output | 33K | 128K |
| Open weights | no | no |
| Reasoning model | no | yes |
| Multimodal input | text, image | text, image |
| Knowledge cutoff | Jun 2024 | Sep 2024 |
| Released | Apr 2025 | Nov 2025 |
| Example monthly cost* | $32.00 | $27.50 |
* 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-4.1 or GPT-5.1?
- GPT-5.1 wins 2 of the 2 benchmarks these models share, against 0 for GPT-4.1. GPT-5.1 is about 1.0x cheaper per blended million tokens (3:1 input:output mix). GPT-4.1 also takes 1M of context versus 400K for GPT-5.1.
- Which is cheaper, GPT-4.1 or GPT-5.1?
- GPT-4.1 costs $2/$8 per million input/output tokens, while GPT-5.1 costs $1.25/$10. For a typical workload of 10M input and 1.5M output tokens per month, that's $32.00 versus $27.50.
- Which model is better for coding, GPT-4.1 or GPT-5.1?
- On SWE-bench Verified — the standard agentic-coding benchmark — GPT-5.1 scores 76.3% versus 54.6% for GPT-4.1, making GPT-5.1 the stronger pick for coding agents.