Model comparison
GPT-5.3 Codex vs GPT-5 Pro
GPT-5.3 Codex and GPT-5 Pro score almost the same on the Noometry Index (45.8 vs 46.4), so choose on price, context window or the category you care about most.
Last verified . 2 shared benchmarks.
Summary
- They share 2 benchmarks with published results for both. GPT-5.3 Codex scores higher in 1 category and GPT-5 Pro in 0 categories; one gap is clear of the uncertainty.
- The widest gap is in coding, where GPT-5.3 Codex leads 48.6 to 44.0.
- The biggest single-benchmark swing is WeirdML: 79.3% for GPT-5.3 Codex and 60.4% for GPT-5 Pro.
- GPT-5.3 Codex is cheaper at $1.75 / $14 per million input/output tokens, against $15 / $120 for GPT-5 Pro.
Side by side
| GPT-5.3 Codex | GPT-5 Pro | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 45.8 | 46.4 |
| Released | 2026-02-05 | 2025-10-06 |
| Weights | Proprietary | Proprietary |
| Context window | 400K | 400K |
| Max output | 128K | 272K |
| Input $ / M tokens | $1.75 | $15 |
| Output $ / M tokens | $14 | $120 |
| Results tracked | 8 | 12 |
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Category by category
Coding GPT-5.3 Codex leads
GPT-5.3 Codex: 48.6 (#56), GPT-5 Pro: 44.0 (#80)
| Benchmark | GPT-5.3 Codex | GPT-5 Pro |
|---|---|---|
| WeirdML | 79.3% | 60.4% |
| SWE-bench Verified | 74.8% | — |
| LMArena WebDev | 1409 | — |
| ALE-Bench | 1,655 | — |
| AlgoTune | — | 1.31 |
Agentic & Tool Use Not comparable
GPT-5.3 Codex: 48.0 (#9), GPT-5 Pro: —
| Benchmark | GPT-5.3 Codex | GPT-5 Pro |
|---|---|---|
| Terminal-Bench | 78.4% | — |
| METR Time Horizons | 74.5% | — |
| Vending-Bench 2 | 5,940 | — |
Reasoning Not comparable
GPT-5.3 Codex: —, GPT-5 Pro: 38.9 (#62)
| Benchmark | GPT-5.3 Codex | GPT-5 Pro |
|---|---|---|
| Epoch Capabilities Index | 156.77 | 150.28 |
| ARC-AGI-2 | — | 18.3% |
| SimpleBench | — | 61.6% |
| Kagi LLM Benchmark | — | 76.8% |
| ARC-AGI-1 | — | 70.2% |
| EnigmaEval | — | 18.8% |
Math Not comparable
GPT-5.3 Codex: —, GPT-5 Pro: 48.5 (#63)
| Benchmark | GPT-5.3 Codex | GPT-5 Pro |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 55.8% |
| FrontierMath Tier 4 | — | 19.5% |
| FrontierMath Tier 4 (v1) | — | 14.6% |
Knowledge Not comparable
GPT-5.3 Codex: —, GPT-5 Pro: 56.7 (#42)
| Benchmark | GPT-5.3 Codex | GPT-5 Pro |
|---|---|---|
| Humanity's Last Exam | — | 31.6% |
Frequently asked questions
Is GPT-5.3 Codex better than GPT-5 Pro?
GPT-5.3 Codex and GPT-5 Pro score almost the same on the Noometry Index (45.8 vs 46.4), so choose on price, context window or the category you care about most.
Which is cheaper, GPT-5.3 Codex or GPT-5 Pro?
GPT-5.3 Codex is cheaper. It lists at $1.75 per million input tokens and $14 per million output tokens; GPT-5 Pro lists at $15 and $120.
Is GPT-5.3 Codex or GPT-5 Pro better for coding?
GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 44.0 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 Pro share?
2 benchmarks have published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and GPT-5 Pro has 12.