Model comparison
GPT-5.3 Chat vs GPT-5.5 Pro
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 42.1 on the Noometry Index. GPT-5.3 Chat costs 14× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.
Last verified . 0 shared benchmarks.
Summary
- The widest gap is in math, where GPT-5.5 Pro leads 83.8 to 35.4.
- GPT-5.3 Chat is cheaper at $1.75 / $14 per million input/output tokens, against $30 / $180 for GPT-5.5 Pro.
- GPT-5.5 Pro accepts more context: 1.05M tokens versus 128K.
Side by side
| GPT-5.3 Chat | GPT-5.5 Pro | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 42.1 | 64.3 |
| Released | 2026-03-03 | 2026-04-23 |
| Weights | Proprietary | Proprietary |
| Context window | 128K | 1.05M |
| Max output | 16K | 128K |
| Input $ / M tokens | $1.75 | $30 |
| Output $ / M tokens | $14 | $180 |
| Results tracked | 18 | 14 |
Sponsored placements are available on pages like this one. Advertise on Noometry
Category by category
Coding Not comparable
GPT-5.3 Chat: 40.8 (#124), GPT-5.5 Pro: —
| Benchmark | GPT-5.3 Chat | GPT-5.5 Pro |
|---|---|---|
| LMArena Coding | 1408 | — |
Reasoning GPT-5.5 Pro leads
GPT-5.3 Chat: 27.3 (#105), GPT-5.5 Pro: 73.6 (#7)
| Benchmark | GPT-5.3 Chat | GPT-5.5 Pro |
|---|---|---|
| ARC-AGI-2 | — | 84.6% |
| SimpleBench | — | 76.9% |
| ARC-AGI-1 | — | 96.5% |
| CritPt | — | 30.6% |
| Chess Puzzles | — | 64% |
| LMArena Hard Prompts | 1399 | — |
| DTBench | — | 96% |
| LMCA | — | 53.9% |
| Epoch Capabilities Index | — | 162.45 |
Math GPT-5.5 Pro leads
GPT-5.3 Chat: 35.4 (#146), GPT-5.5 Pro: 83.8 (#8)
| Benchmark | GPT-5.3 Chat | GPT-5.5 Pro |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 87.7% |
| FrontierMath Tier 4 | — | 78% |
| OTIS Mock AIME 2024-2025 | — | 100% |
| LMArena Math | 1389 | — |
| FrontierMath (Feb 2025 set) | — | 52.4% |
| FrontierMath Tier 4 (v1) | — | 39.6% |
Knowledge GPT-5.5 Pro leads
GPT-5.3 Chat: 38.2 (#137), GPT-5.5 Pro: 64.2 (#17)
| Benchmark | GPT-5.3 Chat | GPT-5.5 Pro |
|---|---|---|
| GPQA Diamond | — | 93.9% |
| LMArena Expert | 1397 | — |
Multilingual Not comparable
GPT-5.3 Chat: 50.5 (#119), GPT-5.5 Pro: —
| Benchmark | GPT-5.3 Chat | GPT-5.5 Pro |
|---|---|---|
| LMArena Non-English | 1383 | — |
| LMArena Chinese | 1433 | — |
| LMArena French | 1398 | — |
| LMArena German | 1384 | — |
| LMArena Japanese | 1351 | — |
| LMArena Korean | 1347 | — |
| LMArena Russian | 1400 | — |
| LMArena Spanish | 1371 | — |
Instruction Following Not comparable
GPT-5.3 Chat: 73.0 (#124), GPT-5.5 Pro: —
| Benchmark | GPT-5.3 Chat | GPT-5.5 Pro |
|---|---|---|
| LMArena Instruction Following | 1378 | — |
Long Context Not comparable
GPT-5.3 Chat: 42.6 (#115), GPT-5.5 Pro: —
| Benchmark | GPT-5.3 Chat | GPT-5.5 Pro |
|---|---|---|
| LMArena Longer Query | 1396 | — |
Writing & Preference Not comparable
GPT-5.3 Chat: 63.3 (#65), GPT-5.5 Pro: —
| Benchmark | GPT-5.3 Chat | GPT-5.5 Pro |
|---|---|---|
| LMArena Text | 1389 | — |
| LMArena Creative Writing | 1356 | — |
| EQ-Bench Creative Writing | 1690 | — |
| LMArena Multi-Turn | 1413 | — |
Frequently asked questions
Is GPT-5.3 Chat better than GPT-5.5 Pro?
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 42.1 on the Noometry Index. GPT-5.3 Chat costs 14× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.
Which is cheaper, GPT-5.3 Chat or GPT-5.5 Pro?
GPT-5.3 Chat is cheaper. It lists at $1.75 per million input tokens and $14 per million output tokens; GPT-5.5 Pro lists at $30 and $180.
Which has the bigger context window?
GPT-5.5 Pro does, with 1.05M tokens against 128K.
How many benchmarks do GPT-5.3 Chat and GPT-5.5 Pro share?
0 benchmarks have published results for both models. GPT-5.3 Chat has 18 scored results on Noometry and GPT-5.5 Pro has 14.