Model comparison
GPT-5.1-Codex vs Phi-4 Mini
GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 30.9 on the Noometry Index. Phi-4 Mini costs 26× 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.
MicrosoftSummary
- The widest gap is in coding, where GPT-5.1-Codex leads 41.9 to 28.1.
- Phi-4 Mini is cheaper at $0.075 / $0.30 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
- GPT-5.1-Codex accepts more context: 400K tokens versus 128K.
- Phi-4 Mini has downloadable open weights; the other is API-only.
Side by side
| GPT-5.1-Codex | Phi-4 Mini | |
|---|---|---|
| Provider | OpenAI | Microsoft |
| Noometry Index | 38.6 | 30.9 |
| Released | 2025-11-12 | 2024-12-11 |
| Weights | Proprietary | Open |
| Context window | 400K | 128K |
| Max output | 128K | 4K |
| Input $ / M tokens | $1.25 | $0.075 |
| Output $ / M tokens | $10 | $0.30 |
| Results tracked | 6 | 3 |
Sponsored placements are available on pages like this one. Advertise on Noometry
Category by category
Coding GPT-5.1-Codex leads
GPT-5.1-Codex: 41.9 (#116), Phi-4 Mini: 28.1 (#317)
| Benchmark | GPT-5.1-Codex | Phi-4 Mini |
|---|---|---|
| SWE-bench Verified (bash only) | 66% | — |
| LMArena WebDev | 1337 | — |
| SciCode | — | 10.8% |
| ALE-Bench | 1,245 | — |
Agentic & Tool Use Not comparable
GPT-5.1-Codex: 38.0 (#33), Phi-4 Mini: —
| Benchmark | GPT-5.1-Codex | Phi-4 Mini |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |
Reasoning Not comparable
GPT-5.1-Codex: —, Phi-4 Mini: 22.4 (#195)
| Benchmark | GPT-5.1-Codex | Phi-4 Mini |
|---|---|---|
| CritPt | — | 0% |
Math Not comparable
GPT-5.1-Codex: 30.3 (#235), Phi-4 Mini: —
| Benchmark | GPT-5.1-Codex | Phi-4 Mini |
|---|---|---|
| ProofBench | 9% | — |
Knowledge Not comparable
GPT-5.1-Codex: —, Phi-4 Mini: 25.3 (#262)
| Benchmark | GPT-5.1-Codex | Phi-4 Mini |
|---|---|---|
| Vectara Hallucination Rate | — | 23.5% |
Frequently asked questions
Is GPT-5.1-Codex better than Phi-4 Mini?
GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 30.9 on the Noometry Index. Phi-4 Mini costs 26× 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 Phi-4 Mini?
Phi-4 Mini is cheaper. It lists at $0.075 per million input tokens and $0.30 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.
Is GPT-5.1-Codex or Phi-4 Mini better for coding?
GPT-5.1-Codex scores higher on coding benchmarks: 41.9 versus 28.1 in the Noometry coding category.
Which has the bigger context window?
GPT-5.1-Codex does, with 400K tokens against 128K.
How many benchmarks do GPT-5.1-Codex and Phi-4 Mini share?
0 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Phi-4 Mini has 3.