Model comparison
GPT-5.1-Codex vs Grok Build 0.1
GPT-5.1-Codex is the stronger model overall, scoring 38.2 to 35.8 on the Noometry Index. Grok Build 0.1 costs 2.8× less per token, which makes it the better buy when GPT-5.1-Codex's lead doesn't matter for your workload.
Last verified . 0 shared benchmarks.
Summary
- The widest gap is in agentic & tool use, where GPT-5.1-Codex leads 37.8 to 22.5.
- Grok Build 0.1 is cheaper at $1 / $2 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
- GPT-5.1-Codex accepts more context: 400K tokens versus 256K.
Side by side
| GPT-5.1-Codex | Grok Build 0.1 | |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 38.2 | 35.8 |
| Released | 2025-11-12 | 2026-04-16 |
| Weights | Proprietary | Proprietary |
| Context window | 400K | 256K |
| Max output | 128K | 256K |
| Input $ / M tokens | $1.25 | $1 |
| Output $ / M tokens | $10 | $2 |
| Results tracked | 6 | 3 |
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Category by category
Coding Too close to call
GPT-5.1-Codex: 41.7 (#107), Grok Build 0.1: 42.5 (#90)
| Benchmark | GPT-5.1-Codex | Grok Build 0.1 |
|---|---|---|
| SWE-bench Verified (bash only) | 66% | — |
| LMArena WebDev | 1337 | — |
| SciCode | — | 50.2% |
| ALE-Bench | 1,245 | — |
Agentic & Tool Use GPT-5.1-Codex leads
GPT-5.1-Codex: 37.8 (#32), Grok Build 0.1: 22.5 (#122)
| Benchmark | GPT-5.1-Codex | Grok Build 0.1 |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| GBAEval | — | 2.4% |
| METR Time Horizons | 70.8% | — |
Reasoning Not comparable
GPT-5.1-Codex: —, Grok Build 0.1: 31.3 (#73)
| Benchmark | GPT-5.1-Codex | Grok Build 0.1 |
|---|---|---|
| CritPt | — | 9.1% |
Math Not comparable
GPT-5.1-Codex: 29.3 (#218), Grok Build 0.1: —
| Benchmark | GPT-5.1-Codex | Grok Build 0.1 |
|---|---|---|
| ProofBench | 9% | — |
Frequently asked questions
Is GPT-5.1-Codex better than Grok Build 0.1?
GPT-5.1-Codex is the stronger model overall, scoring 38.2 to 35.8 on the Noometry Index. Grok Build 0.1 costs 2.8× less per token, which makes it the better buy when GPT-5.1-Codex's lead doesn't matter for your workload.
Which is cheaper, GPT-5.1-Codex or Grok Build 0.1?
Grok Build 0.1 is cheaper. It lists at $1 per million input tokens and $2 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.
Is GPT-5.1-Codex or Grok Build 0.1 better for coding?
They score almost the same on coding (41.7 vs 42.5); test both on your own repository before choosing.
Which has the bigger context window?
GPT-5.1-Codex does, with 400K tokens against 256K.
How many benchmarks do GPT-5.1-Codex and Grok Build 0.1 share?
0 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Grok Build 0.1 has 3.