Model comparison
GPT-5.3 Codex vs Phi-4
GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 30.9 on the Noometry Index. Phi-4 costs 55× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.
Last verified . 1 shared benchmarks.
MicrosoftSummary
- They share 1 benchmark with published results for both. GPT-5.3 Codex scores higher in 2 categories and Phi-4 in 0 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in agentic & tool use, where GPT-5.3 Codex leads 47.8 to 22.6.
- Phi-4 is cheaper at $0.07 / $0.14 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Codex.
- GPT-5.3 Codex accepts more context: 400K tokens versus 128K.
- Phi-4 has downloadable open weights; the other is API-only.
Side by side
| GPT-5.3 Codex | Phi-4 | |
|---|---|---|
| Provider | OpenAI | Microsoft |
| Noometry Index | 45.5 | 30.9 |
| Released | 2026-02-05 | 2024-12-11 |
| Weights | Proprietary | Open |
| Context window | 400K | 128K |
| Max output | 128K | 4K |
| Input $ / M tokens | $1.75 | $0.07 |
| Output $ / M tokens | $14 | $0.14 |
| Results tracked | 8 | 37 |
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Category by category
Coding GPT-5.3 Codex leads
GPT-5.3 Codex: 48.5 (#51), Phi-4: 33.8 (#237)
| Benchmark | GPT-5.3 Codex | Phi-4 |
|---|---|---|
| SWE-bench Verified | 74.8% | — |
| LMArena WebDev | 1408 | — |
| WeirdML | 79.3% | — |
| BigCodeBench Instruct | — | 45.5% |
| LiveBench Coding | — | 30.7% |
| LMArena Coding | — | 1231 |
| BigCodeBench Complete | — | 55.4% |
| ALE-Bench | 1,655 | — |
Agentic & Tool Use GPT-5.3 Codex leads
GPT-5.3 Codex: 47.8 (#9), Phi-4: 22.6 (#120)
| Benchmark | GPT-5.3 Codex | Phi-4 |
|---|---|---|
| Terminal-Bench | 78.4% | — |
| Berkeley Function Calling Leaderboard | — | 28.8% |
| BALROG | — | 11.6% |
| METR Time Horizons | 74.5% | — |
| Vending-Bench 2 | 5,940 | — |
Reasoning Not comparable
GPT-5.3 Codex: —, Phi-4: 17.0 (#287)
| Benchmark | GPT-5.3 Codex | Phi-4 |
|---|---|---|
| Epoch Capabilities Index | 156.84 | 130.43 |
| Chess Puzzles | — | 1% |
| LiveBench Reasoning | — | 47.8% |
| LMArena Hard Prompts | — | 1220 |
| LiveBench Data Analysis | — | 45.2% |
| LiveBench | — | 41.6% |
Math Not comparable
GPT-5.3 Codex: —, Phi-4: 19.6 (#279)
| Benchmark | GPT-5.3 Codex | Phi-4 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | — | 13.8% |
| LiveBench Math | — | 42% |
| LMArena Math | — | 1246 |
| MATH Level 5 | — | 64.9% |
Knowledge Not comparable
GPT-5.3 Codex: —, Phi-4: 32.5 (#204)
| Benchmark | GPT-5.3 Codex | Phi-4 |
|---|---|---|
| GPQA Diamond | — | 56.1% |
| Confabulations | — | 29.4% |
| Vectara Hallucination Rate | — | 3.7% |
| LMArena Expert | — | 1203 |
| MMLU | — | 84.8% |
Multilingual Not comparable
GPT-5.3 Codex: —, Phi-4: 37.4 (#232)
| Benchmark | GPT-5.3 Codex | Phi-4 |
|---|---|---|
| LMArena Non-English | — | 1197 |
| LMArena Chinese | — | 1211 |
| LMArena French | — | 1223 |
| LMArena German | — | 1222 |
| LMArena Japanese | — | 1158 |
| LMArena Korean | — | 1151 |
| LMArena Russian | — | 1209 |
| LMArena Spanish | — | 1234 |
Instruction Following Not comparable
GPT-5.3 Codex: —, Phi-4: 60.6 (#246)
| Benchmark | GPT-5.3 Codex | Phi-4 |
|---|---|---|
| LiveBench Instruction Following | — | 58.4% |
| LMArena Instruction Following | — | 1201 |
Long Context Not comparable
GPT-5.3 Codex: —, Phi-4: 36.9 (#221)
| Benchmark | GPT-5.3 Codex | Phi-4 |
|---|---|---|
| LMArena Longer Query | — | 1217 |
Writing & Preference Not comparable
GPT-5.3 Codex: —, Phi-4: 40.7 (#239)
| Benchmark | GPT-5.3 Codex | Phi-4 |
|---|---|---|
| LMArena Text | — | 1217 |
| LMArena Creative Writing | — | 1182 |
| Short-Story Creative Writing | — | 62.6% |
| LMArena Multi-Turn | — | 1206 |
| LiveBench Language | — | 25.6% |
Frequently asked questions
Is GPT-5.3 Codex better than Phi-4?
GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 30.9 on the Noometry Index. Phi-4 costs 55× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.
Which is cheaper, GPT-5.3 Codex or Phi-4?
Phi-4 is cheaper. It lists at $0.07 per million input tokens and $0.14 per million output tokens; GPT-5.3 Codex lists at $1.75 and $14.
Is GPT-5.3 Codex or Phi-4 better for coding?
GPT-5.3 Codex scores higher on coding benchmarks: 48.5 versus 33.8 in the Noometry coding category.
Which has the bigger context window?
GPT-5.3 Codex does, with 400K tokens against 128K.
How many benchmarks do GPT-5.3 Codex and Phi-4 share?
1 benchmark has published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and Phi-4 has 37.