Model comparison
GPT-5.3 Codex vs GPT-5 Mini
GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 41.7 on the Noometry Index. GPT-5 Mini costs 7.0× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.
Last verified . 6 shared benchmarks.
Summary
- They share 6 benchmarks with published results for both. GPT-5.3 Codex scores higher in 2 categories and GPT-5 Mini 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 31.0.
- The biggest single-benchmark swing is Terminal-Bench: 78.4% for GPT-5.3 Codex and 34.8% for GPT-5 Mini.
- GPT-5 Mini is cheaper at $0.25 / $2 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Codex.
Side by side
| GPT-5.3 Codex | GPT-5 Mini | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 45.5 | 41.7 |
| Released | 2026-02-05 | 2025-08-07 |
| Weights | Proprietary | Proprietary |
| Context window | 400K | 400K |
| Max output | 128K | 128K |
| Input $ / M tokens | $1.75 | $0.25 |
| Output $ / M tokens | $14 | $2 |
| Results tracked | 8 | 60 |
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Category by category
Coding GPT-5.3 Codex leads
GPT-5.3 Codex: 48.5 (#51), GPT-5 Mini: 40.0 (#134)
| Benchmark | GPT-5.3 Codex | GPT-5 Mini |
|---|---|---|
| SWE-bench Verified | 74.8% | 64.7% |
| WeirdML | 79.3% | 52.7% |
| ALE-Bench | 1,655 | 799.77 |
| SWE-bench Verified (bash only) | — | 59.8% |
| LMArena WebDev | 1408 | — |
| SWE-bench Multilingual | — | 39.7% |
| SciCode | — | 39.2% |
| LMArena Coding | — | 1406 |
| AlgoTune | — | 1.38 |
Agentic & Tool Use GPT-5.3 Codex leads
GPT-5.3 Codex: 47.8 (#9), GPT-5 Mini: 31.0 (#64)
| Benchmark | GPT-5.3 Codex | GPT-5 Mini |
|---|---|---|
| Terminal-Bench | 78.4% | 34.8% |
| Vending-Bench 2 | 5,940 | -31.18 |
| Berkeley Function Calling Leaderboard | — | 55.5% |
| METR Time Horizons | 74.5% | — |
Reasoning Not comparable
GPT-5.3 Codex: —, GPT-5 Mini: 24.1 (#153)
| Benchmark | GPT-5.3 Codex | GPT-5 Mini |
|---|---|---|
| Epoch Capabilities Index | 156.84 | 145.51 |
| ARC-AGI-2 | — | 4.4% |
| Kagi LLM Benchmark | — | 70.3% |
| ARC-AGI-1 | — | 54.3% |
| CritPt | — | 0% |
| Chess Puzzles | — | 30% |
| EnigmaEval | — | 8.2% |
| LMArena Hard Prompts | — | 1380 |
| Mystery Game Puzzles | — | 10% |
| DTBench | — | 80.5% |
| LMCA | — | 34.2% |
| ForecastBench | — | 61 |
Math Not comparable
GPT-5.3 Codex: —, GPT-5 Mini: 46.3 (#59)
| Benchmark | GPT-5.3 Codex | GPT-5 Mini |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 46.7% |
| FrontierMath Tier 4 | — | 12.2% |
| OTIS Mock AIME 2024-2025 | — | 86.7% |
| ProofBench | — | 9% |
| Omni-MATH | — | 72.2% |
| LMArena Math | — | 1377 |
| MATH Level 5 | — | 97.8% |
| FrontierMath (Feb 2025 set) | — | 27.2% |
| FrontierMath Tier 4 (v1) | — | 6.3% |
Knowledge Not comparable
GPT-5.3 Codex: —, GPT-5 Mini: 45.5 (#80)
| Benchmark | GPT-5.3 Codex | GPT-5 Mini |
|---|---|---|
| GPQA Diamond | — | 75% |
| Humanity's Last Exam | — | 19.4% |
| SimpleQA Verified | — | 21.6% |
| MMLU-Pro | — | 83.5% |
| Confabulations | — | 13.3% |
| Vectara Hallucination Rate | — | 12.9% |
| GPQA (HELM) | — | 75.6% |
| LMArena Expert | — | 1377 |
Multimodal Not comparable
GPT-5.3 Codex: —, GPT-5 Mini: 35.0 (#80)
| Benchmark | GPT-5.3 Codex | GPT-5 Mini |
|---|---|---|
| LMArena Vision | — | 1202 |
| VPCT | — | 40.2% |
Multilingual Not comparable
GPT-5.3 Codex: —, GPT-5 Mini: 49.1 (#131)
| Benchmark | GPT-5.3 Codex | GPT-5 Mini |
|---|---|---|
| LMArena Non-English | — | 1363 |
| LMArena Chinese | — | 1387 |
| LMArena French | — | 1385 |
| LMArena German | — | 1366 |
| LMArena Japanese | — | 1342 |
| LMArena Korean | — | 1306 |
| LMArena Russian | — | 1362 |
| LMArena Spanish | — | 1355 |
Instruction Following Not comparable
GPT-5.3 Codex: —, GPT-5 Mini: 76.4 (#43)
| Benchmark | GPT-5.3 Codex | GPT-5 Mini |
|---|---|---|
| IFEval | — | 92.7% |
| LMArena Instruction Following | — | 1357 |
Long Context Not comparable
GPT-5.3 Codex: —, GPT-5 Mini: 41.9 (#127)
| Benchmark | GPT-5.3 Codex | GPT-5 Mini |
|---|---|---|
| Fiction.LiveBench | — | 69.4% |
| LMArena Longer Query | — | 1355 |
Writing & Preference Not comparable
GPT-5.3 Codex: —, GPT-5 Mini: 55.4 (#143)
| Benchmark | GPT-5.3 Codex | GPT-5 Mini |
|---|---|---|
| LMArena Text | — | 1373 |
| LMArena Creative Writing | — | 1325 |
| Short-Story Creative Writing | — | 83.1% |
| EQ-Bench Creative Writing | — | 1313 |
| WildBench | — | 85.5% |
| LMArena Multi-Turn | — | 1363 |
Frequently asked questions
Is GPT-5.3 Codex better than GPT-5 Mini?
GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 41.7 on the Noometry Index. GPT-5 Mini costs 7.0× 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 GPT-5 Mini?
GPT-5 Mini is cheaper. It lists at $0.25 per million input tokens and $2 per million output tokens; GPT-5.3 Codex lists at $1.75 and $14.
Is GPT-5.3 Codex or GPT-5 Mini better for coding?
GPT-5.3 Codex scores higher on coding benchmarks: 48.5 versus 40.0 in the Noometry coding category.
Which has the bigger context window?
Both accept 400K tokens.
How many benchmarks do GPT-5.3 Codex and GPT-5 Mini share?
6 benchmarks have published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and GPT-5 Mini has 60.