Model comparison
GPT-5.1 vs Phi-4
GPT-5.1 is the stronger model overall, scoring 49.0 to 31.2 on the Noometry Index. Phi-4 costs 39× less per token, which makes it the better buy when GPT-5.1's lead doesn't matter for your workload.
Last verified . 29 shared benchmarks.
MicrosoftSummary
- They share 29 benchmarks with published results for both. GPT-5.1 scores higher in 9 categories and Phi-4 in 0 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.1 leads 52.2 to 20.8.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 88.6% for GPT-5.1 and 13.8% for Phi-4.
- Phi-4 is cheaper at $0.07 / $0.14 per million input/output tokens, against $1.25 / $10 for GPT-5.1.
- GPT-5.1 accepts more context: 400K tokens versus 128K.
- Phi-4 has downloadable open weights; the other is API-only.
Side by side
| GPT-5.1 | Phi-4 | |
|---|---|---|
| Provider | OpenAI | Microsoft |
| Noometry Index | 49.0 | 31.2 |
| Released | 2025-11-13 | 2024-12-11 |
| Weights | Proprietary | Open |
| Context window | 400K | 128K |
| Max output | 128K | 4K |
| Input $ / M tokens | $1.25 | $0.07 |
| Output $ / M tokens | $10 | $0.14 |
| Results tracked | 63 | 37 |
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Category by category
Coding GPT-5.1 leads
GPT-5.1: 46.4 (#66), Phi-4: 34.4 (#239)
| Benchmark | GPT-5.1 | Phi-4 |
|---|---|---|
| LiveBench Coding | 72.5% | 30.7% |
| LMArena Coding | 1454 | 1231 |
| SWE-bench Verified | 68% | — |
| SWE-bench Verified (bash only) | 66% | — |
| LMArena WebDev | 1395 | — |
| SciCode | 43.3% | — |
| GSO | 13.7% | — |
| WeirdML | 60.8% | — |
| BigCodeBench Instruct | — | 45.5% |
| BigCodeBench Complete | — | 55.4% |
| ALE-Bench | 1,192 | — |
Agentic & Tool Use GPT-5.1 leads
GPT-5.1: 32.7 (#60), Phi-4: 22.8 (#128)
| Benchmark | GPT-5.1 | Phi-4 |
|---|---|---|
| Terminal-Bench | 47.6% | — |
| Berkeley Function Calling Leaderboard | — | 28.8% |
| DeepResearch Bench | 42.8% | — |
| BALROG | — | 11.6% |
| LMArena Search | 1199 | — |
| Vending-Bench 2 | 1,473 | — |
Reasoning GPT-5.1 leads
GPT-5.1: 39.8 (#58), Phi-4: 17.7 (#291)
| Benchmark | GPT-5.1 | Phi-4 |
|---|---|---|
| Chess Puzzles | 32% | 1% |
| LiveBench Reasoning | 95.8% | 47.8% |
| LMArena Hard Prompts | 1457 | 1220 |
| LiveBench Data Analysis | 72.1% | 45.2% |
| Epoch Capabilities Index | 149.64 | 130.42 |
| LiveBench | 78.8% | 41.6% |
| ARC-AGI-2 | 17.6% | — |
| SimpleBench | 53.2% | — |
| ARC-AGI-1 | 72.8% | — |
| CritPt | 4.9% | — |
| EnigmaEval | 11.2% | — |
| Mystery Game Puzzles | 19% | — |
| DTBench | 90.1% | — |
| LMCA | 43.9% | — |
| ForecastBench | 58.1 | — |
Math GPT-5.1 leads
GPT-5.1: 52.2 (#51), Phi-4: 20.8 (#285)
| Benchmark | GPT-5.1 | Phi-4 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 88.6% | 13.8% |
| LiveBench Math | 94.5% | 42% |
| LMArena Math | 1447 | 1246 |
| Omni-MATH | 46.4% | — |
| MATH Level 5 | — | 64.9% |
| FrontierMath (Feb 2025 set) | 31% | — |
| FrontierMath Tier 4 (v1) | 12.5% | — |
Knowledge GPT-5.1 leads
GPT-5.1: 50.6 (#71), Phi-4: 32.6 (#209)
| Benchmark | GPT-5.1 | Phi-4 |
|---|---|---|
| GPQA Diamond | 87.6% | 56.1% |
| Vectara Hallucination Rate | 10.9% | 3.7% |
| LMArena Expert | 1470 | 1203 |
| Humanity's Last Exam | 23.7% | — |
| SimpleQA Verified | 48% | — |
| MMLU-Pro | 57.9% | — |
| Confabulations | — | 29.4% |
| GPQA (HELM) | 44.2% | — |
| MMLU | — | 84.8% |
Multimodal Not comparable
GPT-5.1: 44.8 (#19), Phi-4: —
| Benchmark | GPT-5.1 | Phi-4 |
|---|---|---|
| LMArena Vision | 1250 | — |
| VPCT | 58.7% | — |
| LMArena Document | 1403 | — |
Multilingual GPT-5.1 leads
GPT-5.1: 53.8 (#56), Phi-4: 37.2 (#237)
| Benchmark | GPT-5.1 | Phi-4 |
|---|---|---|
| LMArena Non-English | 1431 | 1197 |
| LMArena Chinese | 1495 | 1212 |
| LMArena French | 1450 | 1224 |
| LMArena German | 1438 | 1222 |
| LMArena Japanese | 1453 | 1158 |
| LMArena Korean | 1401 | 1151 |
| LMArena Russian | 1435 | 1209 |
| LMArena Spanish | 1433 | 1234 |
Instruction Following GPT-5.1 leads
GPT-5.1: 83.9 (#1), Phi-4: 60.4 (#251)
| Benchmark | GPT-5.1 | Phi-4 |
|---|---|---|
| LiveBench Instruction Following | 93.3% | 58.4% |
| LMArena Instruction Following | 1443 | 1201 |
| IFEval | 93.5% | — |
Long Context GPT-5.1 leads
GPT-5.1: 47.6 (#14), Phi-4: 36.9 (#226)
| Benchmark | GPT-5.1 | Phi-4 |
|---|---|---|
| LMArena Longer Query | 1447 | 1217 |
| CL-bench | 23.7% | — |
| CL-bench Life | 17.3% | — |
Writing & Preference GPT-5.1 leads
GPT-5.1: 64.5 (#55), Phi-4: 40.5 (#244)
| Benchmark | GPT-5.1 | Phi-4 |
|---|---|---|
| LMArena Text | 1443 | 1217 |
| LMArena Creative Writing | 1427 | 1182 |
| LMArena Multi-Turn | 1450 | 1206 |
| LiveBench Language | 80.2% | 25.6% |
| Short-Story Creative Writing | — | 62.6% |
| WildBench | 86.3% | — |
Frequently asked questions
Is GPT-5.1 better than Phi-4?
GPT-5.1 is the stronger model overall, scoring 49.0 to 31.2 on the Noometry Index. Phi-4 costs 39× less per token, which makes it the better buy when GPT-5.1's lead doesn't matter for your workload.
Which is cheaper, GPT-5.1 or Phi-4?
Phi-4 is cheaper. It lists at $0.07 per million input tokens and $0.14 per million output tokens; GPT-5.1 lists at $1.25 and $10.
Is GPT-5.1 or Phi-4 better for coding?
GPT-5.1 scores higher on coding benchmarks: 46.4 versus 34.4 in the Noometry coding category.
Which has the bigger context window?
GPT-5.1 does, with 400K tokens against 128K.
How many benchmarks do GPT-5.1 and Phi-4 share?
29 benchmarks have published results for both models. GPT-5.1 has 63 scored results on Noometry and Phi-4 has 37.