Model comparison
GPT-5.5 Instant vs GPT-5 Pro
GPT-5 Pro is the stronger model overall, scoring 46.4 to 42.7 on the Noometry Index.
Last verified . 3 shared benchmarks.
Summary
- They share 3 benchmarks with published results for both. GPT-5.5 Instant scores higher in 1 category and GPT-5 Pro in 3 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5 Pro leads 48.5 to 26.5.
- The biggest single-benchmark swing is FrontierMath (Tiers 1-3): 26.3% for GPT-5.5 Instant and 55.8% for GPT-5 Pro.
Side by side
| GPT-5.5 Instant | GPT-5 Pro | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 42.7 | 46.4 |
| Released | 2026-05-05 | 2025-10-06 |
| Weights | Proprietary | Proprietary |
| Context window | — | 400K |
| Max output | — | 272K |
| Input $ / M tokens | — | $15 |
| Output $ / M tokens | — | $120 |
| Results tracked | 27 | 12 |
Sponsored placements are available on pages like this one. Advertise on Noometry
Category by category
Coding Too close to call
GPT-5.5 Instant: 44.3 (#74), GPT-5 Pro: 44.0 (#80)
| Benchmark | GPT-5.5 Instant | GPT-5 Pro |
|---|---|---|
| SciCode | 48.6% | — |
| WeirdML | — | 60.4% |
| LMArena Coding | 1433 | — |
| AlgoTune | — | 1.31 |
Reasoning GPT-5 Pro leads
GPT-5.5 Instant: 24.9 (#155), GPT-5 Pro: 38.9 (#62)
| Benchmark | GPT-5.5 Instant | GPT-5 Pro |
|---|---|---|
| Epoch Capabilities Index | 142.52 | 150.28 |
| ARC-AGI-2 | — | 18.3% |
| SimpleBench | — | 61.6% |
| Kagi LLM Benchmark | — | 76.8% |
| ARC-AGI-1 | — | 70.2% |
| CritPt | 0% | — |
| Chess Puzzles | 12% | — |
| EnigmaEval | — | 18.8% |
| LMArena Hard Prompts | 1426 | — |
Math GPT-5 Pro leads
GPT-5.5 Instant: 26.5 (#259), GPT-5 Pro: 48.5 (#63)
| Benchmark | GPT-5.5 Instant | GPT-5 Pro |
|---|---|---|
| FrontierMath (Tiers 1-3) | 26.3% | 55.8% |
| FrontierMath Tier 4 | 2.4% | 19.5% |
| OTIS Mock AIME 2024-2025 | 68.1% | — |
| LMArena Math | 1420 | — |
| FrontierMath Tier 4 (v1) | — | 14.6% |
Knowledge GPT-5 Pro leads
GPT-5.5 Instant: 48.9 (#74), GPT-5 Pro: 56.7 (#42)
| Benchmark | GPT-5.5 Instant | GPT-5 Pro |
|---|---|---|
| GPQA Diamond | 82.5% | — |
| Humanity's Last Exam | — | 31.6% |
| LMArena Expert | 1409 | — |
Multimodal Not comparable
GPT-5.5 Instant: 40.0 (#52), GPT-5 Pro: —
| Benchmark | GPT-5.5 Instant | GPT-5 Pro |
|---|---|---|
| LMArena Vision | 1250 | — |
| LMArena Document | 1403 | — |
Multilingual Not comparable
GPT-5.5 Instant: 52.8 (#80), GPT-5 Pro: —
| Benchmark | GPT-5.5 Instant | GPT-5 Pro |
|---|---|---|
| LMArena Non-English | 1417 | — |
| LMArena Chinese | 1456 | — |
| LMArena French | 1428 | — |
| LMArena German | 1411 | — |
| LMArena Japanese | 1408 | — |
| LMArena Korean | 1392 | — |
| LMArena Russian | 1431 | — |
| LMArena Spanish | 1429 | — |
Instruction Following Not comparable
GPT-5.5 Instant: 74.2 (#100), GPT-5 Pro: —
| Benchmark | GPT-5.5 Instant | GPT-5 Pro |
|---|---|---|
| LMArena Instruction Following | 1406 | — |
Long Context Not comparable
GPT-5.5 Instant: 43.4 (#96), GPT-5 Pro: —
| Benchmark | GPT-5.5 Instant | GPT-5 Pro |
|---|---|---|
| LMArena Longer Query | 1422 | — |
Writing & Preference Not comparable
GPT-5.5 Instant: 61.8 (#85), GPT-5 Pro: —
| Benchmark | GPT-5.5 Instant | GPT-5 Pro |
|---|---|---|
| LMArena Text | 1419 | — |
| LMArena Creative Writing | 1419 | — |
| LMArena Multi-Turn | 1433 | — |
Frequently asked questions
Is GPT-5.5 Instant better than GPT-5 Pro?
GPT-5 Pro is the stronger model overall, scoring 46.4 to 42.7 on the Noometry Index.
Is GPT-5.5 Instant or GPT-5 Pro better for coding?
They score almost the same on coding (44.3 vs 44.0); test both on your own repository before choosing.
How many benchmarks do GPT-5.5 Instant and GPT-5 Pro share?
3 benchmarks have published results for both models. GPT-5.5 Instant has 27 scored results on Noometry and GPT-5 Pro has 12.