Model comparison
GPT-5.2 Codex vs GPT-5.3 Chat
GPT-5.2 Codex and GPT-5.3 Chat score almost the same on the Noometry Index (42.6 vs 42.8), so choose on price, context window or the category you care about most.
Last verified . 0 shared benchmarks.
Summary
- The widest gap is in coding, where GPT-5.2 Codex leads 45.5 to 41.4.
- Both cost about the same: $1.75 input and $14 output per million tokens.
- GPT-5.2 Codex accepts more context: 400K tokens versus 128K.
Side by side
| GPT-5.2 Codex | GPT-5.3 Chat | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 42.6 | 42.8 |
| Released | 2025-12-18 | 2026-03-03 |
| Weights | Proprietary | Proprietary |
| Context window | 400K | 128K |
| Max output | 128K | 16K |
| Input $ / M tokens | $1.75 | $1.75 |
| Output $ / M tokens | $14 | $14 |
| Results tracked | 5 | 18 |
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Category by category
Coding GPT-5.2 Codex leads
GPT-5.2 Codex: 45.5 (#71), GPT-5.3 Chat: 41.4 (#124)
| Benchmark | GPT-5.2 Codex | GPT-5.3 Chat |
|---|---|---|
| SWE-bench Verified (bash only) | 72.8% | — |
| LMArena WebDev | 1339 | — |
| SWE-bench Multilingual | 66.3% | — |
| LMArena Coding | — | 1408 |
| ALE-Bench | 1,300 | — |
Agentic & Tool Use Not comparable
GPT-5.2 Codex: 41.0 (#22), GPT-5.3 Chat: —
| Benchmark | GPT-5.2 Codex | GPT-5.3 Chat |
|---|---|---|
| Terminal-Bench | 66.5% | — |
Reasoning Not comparable
GPT-5.2 Codex: —, GPT-5.3 Chat: 28.5 (#102)
| Benchmark | GPT-5.2 Codex | GPT-5.3 Chat |
|---|---|---|
| LMArena Hard Prompts | — | 1399 |
Math Not comparable
GPT-5.2 Codex: —, GPT-5.3 Chat: 38.2 (#142)
| Benchmark | GPT-5.2 Codex | GPT-5.3 Chat |
|---|---|---|
| LMArena Math | — | 1389 |
Knowledge Not comparable
GPT-5.2 Codex: —, GPT-5.3 Chat: 38.8 (#140)
| Benchmark | GPT-5.2 Codex | GPT-5.3 Chat |
|---|---|---|
| LMArena Expert | — | 1397 |
Multilingual Not comparable
GPT-5.2 Codex: —, GPT-5.3 Chat: 50.3 (#124)
| Benchmark | GPT-5.2 Codex | GPT-5.3 Chat |
|---|---|---|
| LMArena Non-English | — | 1382 |
| LMArena Chinese | — | 1432 |
| LMArena French | — | 1397 |
| LMArena German | — | 1384 |
| LMArena Japanese | — | 1352 |
| LMArena Korean | — | 1346 |
| LMArena Russian | — | 1400 |
| LMArena Spanish | — | 1371 |
Instruction Following Not comparable
GPT-5.2 Codex: —, GPT-5.3 Chat: 72.8 (#129)
| Benchmark | GPT-5.2 Codex | GPT-5.3 Chat |
|---|---|---|
| LMArena Instruction Following | — | 1378 |
Long Context Not comparable
GPT-5.2 Codex: —, GPT-5.3 Chat: 42.6 (#120)
| Benchmark | GPT-5.2 Codex | GPT-5.3 Chat |
|---|---|---|
| LMArena Longer Query | — | 1396 |
Writing & Preference Not comparable
GPT-5.2 Codex: —, GPT-5.3 Chat: 63.1 (#68)
| Benchmark | GPT-5.2 Codex | GPT-5.3 Chat |
|---|---|---|
| LMArena Text | — | 1389 |
| LMArena Creative Writing | — | 1355 |
| EQ-Bench Creative Writing | — | 1690 |
| LMArena Multi-Turn | — | 1412 |
Frequently asked questions
Is GPT-5.2 Codex better than GPT-5.3 Chat?
GPT-5.2 Codex and GPT-5.3 Chat score almost the same on the Noometry Index (42.6 vs 42.8), so choose on price, context window or the category you care about most.
Which is cheaper, GPT-5.2 Codex or GPT-5.3 Chat?
GPT-5.3 Chat is cheaper. It lists at $1.75 per million input tokens and $14 per million output tokens; GPT-5.2 Codex lists at $1.75 and $14.
Is GPT-5.2 Codex or GPT-5.3 Chat better for coding?
GPT-5.2 Codex scores higher on coding benchmarks: 45.5 versus 41.4 in the Noometry coding category.
Which has the bigger context window?
GPT-5.2 Codex does, with 400K tokens against 128K.
How many benchmarks do GPT-5.2 Codex and GPT-5.3 Chat share?
0 benchmarks have published results for both models. GPT-5.2 Codex has 5 scored results on Noometry and GPT-5.3 Chat has 18.