Model comparison
Gemini 2.5 Pro vs GPT-5.5 Instant
Gemini 2.5 Pro is the stronger model overall, scoring 44.9 to 42.5 on the Noometry Index.
Last verified . 27 shared benchmarks.
GoogleSummary
- They share 27 benchmarks with published results for both. Gemini 2.5 Pro scores higher in 8 categories and GPT-5.5 Instant in 1 category; 7 gaps are clear of the uncertainty.
- The widest gap is in long context, where Gemini 2.5 Pro leads 59.7 to 43.4.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 84.7% for Gemini 2.5 Pro and 68.1% for GPT-5.5 Instant.
Side by side
| Gemini 2.5 Pro | GPT-5.5 Instant | |
|---|---|---|
| Provider | OpenAI | |
| Noometry Index | 44.9 | 42.5 |
| Released | 2025-03-25 | 2026-05-05 |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | — |
| Max output | 66K | — |
| Input $ / M tokens | $1.25 | — |
| Output $ / M tokens | $10 | — |
| Results tracked | 78 | 27 |
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Category by category
Coding Too close to call
Gemini 2.5 Pro: 42.8 (#86), GPT-5.5 Instant: 43.7 (#73)
| Benchmark | Gemini 2.5 Pro | GPT-5.5 Instant |
|---|---|---|
| SciCode | 42.8% | 48.6% |
| LMArena Coding | 1452 | 1433 |
| SWE-bench Verified | 57.6% | — |
| SWE-bench Verified (bash only) | 53.6% | — |
| Aider Polyglot | 83.1% | — |
| LMArena WebDev | 1227 | — |
| GSO | 3.9% | — |
| WeirdML | 54% | — |
| LiveBench Coding | 85.9% | — |
| CadEval | 64% | — |
| ALE-Bench | 785.52 | — |
| AlgoTune | 1.51 | — |
Agentic & Tool Use Not comparable
Gemini 2.5 Pro: 29.1 (#81), GPT-5.5 Instant: —
| Benchmark | Gemini 2.5 Pro | GPT-5.5 Instant |
|---|---|---|
| Terminal-Bench | 32.6% | — |
| GDPval | 23.3% | — |
| Remote Labor Index | 0.8% | — |
| TheAgentCompany | 30.3% | — |
| τ²-bench Banking | 13.7% | — |
| DeepResearch Bench | 42.8% | — |
| BALROG | 43.3% | — |
| LMArena Search | 1142 | — |
| METR Time Horizons | 55.4% | — |
| Vending-Bench 2 | 573.64 | — |
Reasoning Gemini 2.5 Pro leads
Gemini 2.5 Pro: 28.8 (#85), GPT-5.5 Instant: 24.2 (#149)
| Benchmark | Gemini 2.5 Pro | GPT-5.5 Instant |
|---|---|---|
| CritPt | 2% | 0% |
| Chess Puzzles | 20% | 12% |
| LMArena Hard Prompts | 1455 | 1426 |
| Epoch Capabilities Index | 145.32 | 142.48 |
| ARC-AGI-2 | 4.9% | — |
| SimpleBench | 62.4% | — |
| Kagi LLM Benchmark | 70.3% | — |
| ARC-AGI-1 | 41% | — |
| EnigmaEval | 5.6% | — |
| LiveBench Reasoning | 89.8% | — |
| DTBench | 82.4% | — |
| LiveBench Data Analysis | 79.9% | — |
| LMCA | 34.8% | — |
| ForecastBench | 61.3 | — |
| LiveBench | 82.3% | — |
Math Gemini 2.5 Pro leads
Gemini 2.5 Pro: 31.9 (#191), GPT-5.5 Instant: 26.1 (#241)
| Benchmark | Gemini 2.5 Pro | GPT-5.5 Instant |
|---|---|---|
| FrontierMath (Tiers 1-3) | 24.6% | 26.3% |
| FrontierMath Tier 4 | 0% | 2.4% |
| OTIS Mock AIME 2024-2025 | 84.7% | 68.1% |
| LMArena Math | 1450 | 1420 |
| Omni-MATH | 41.6% | — |
| LiveBench Math | 90.2% | — |
| MATH Level 5 | 95.9% | — |
| FrontierMath (Feb 2025 set) | 14.1% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |
Knowledge Gemini 2.5 Pro leads
Gemini 2.5 Pro: 55.8 (#41), GPT-5.5 Instant: 48.9 (#68)
| Benchmark | Gemini 2.5 Pro | GPT-5.5 Instant |
|---|---|---|
| GPQA Diamond | 85.3% | 82.5% |
| LMArena Expert | 1452 | 1409 |
| Humanity's Last Exam | 21.6% | — |
| MMLU-Pro | 86.3% | — |
| Confabulations | 10.6% | — |
| Vectara Hallucination Rate | 7% | — |
| GPQA (HELM) | 74.9% | — |
Multimodal Gemini 2.5 Pro leads
Gemini 2.5 Pro: 44.5 (#16), GPT-5.5 Instant: 39.3 (#48)
| Benchmark | Gemini 2.5 Pro | GPT-5.5 Instant |
|---|---|---|
| LMArena Vision | 1263 | 1250 |
| LMArena Document | 1421 | 1403 |
| GeoBench | 86% | — |
| VPCT | 48% | — |
| SpatialViz-Bench | 44.7% | — |
Multilingual Gemini 2.5 Pro leads
Gemini 2.5 Pro: 55.5 (#30), GPT-5.5 Instant: 53.0 (#76)
| Benchmark | Gemini 2.5 Pro | GPT-5.5 Instant |
|---|---|---|
| LMArena Non-English | 1452 | 1417 |
| LMArena Chinese | 1507 | 1457 |
| LMArena French | 1473 | 1428 |
| LMArena German | 1487 | 1410 |
| LMArena Japanese | 1462 | 1408 |
| LMArena Korean | 1435 | 1393 |
| LMArena Russian | 1460 | 1430 |
| LMArena Spanish | 1473 | 1430 |
Instruction Following Too close to call
Gemini 2.5 Pro: 75.2 (#71), GPT-5.5 Instant: 74.4 (#94)
| Benchmark | Gemini 2.5 Pro | GPT-5.5 Instant |
|---|---|---|
| LMArena Instruction Following | 1436 | 1407 |
| LiveBench Instruction Following | 80.6% | — |
| IFEval | 84% | — |
Long Context Gemini 2.5 Pro leads
Gemini 2.5 Pro: 59.7 (#5), GPT-5.5 Instant: 43.4 (#92)
| Benchmark | Gemini 2.5 Pro | GPT-5.5 Instant |
|---|---|---|
| LMArena Longer Query | 1449 | 1422 |
| Fiction.LiveBench | 91.7% | — |
Writing & Preference Gemini 2.5 Pro leads
Gemini 2.5 Pro: 63.9 (#60), GPT-5.5 Instant: 62.0 (#81)
| Benchmark | Gemini 2.5 Pro | GPT-5.5 Instant |
|---|---|---|
| LMArena Text | 1458 | 1419 |
| LMArena Creative Writing | 1453 | 1420 |
| LMArena Multi-Turn | 1453 | 1434 |
| Short-Story Creative Writing | 83.8% | — |
| EQ-Bench Creative Writing | 1421 | — |
| WildBench | 85.7% | — |
| LiveBench Language | 67.8% | — |
Frequently asked questions
Is Gemini 2.5 Pro better than GPT-5.5 Instant?
Gemini 2.5 Pro is the stronger model overall, scoring 44.9 to 42.5 on the Noometry Index.
Is Gemini 2.5 Pro or GPT-5.5 Instant better for coding?
They score almost the same on coding (42.8 vs 43.7); test both on your own repository before choosing.
How many benchmarks do Gemini 2.5 Pro and GPT-5.5 Instant share?
27 benchmarks have published results for both models. Gemini 2.5 Pro has 78 scored results on Noometry and GPT-5.5 Instant has 27.