GPT-5.5 vs Kimi K3.1 Pro Together
Full profiles: GPT-5.5 (OpenAI) and Kimi K3.1 Pro Together (Moonshot AI): every benchmark, price and rank.
Updated · Data from 13 sources
As of 9 Nov 2026, GPT-5.5 and Kimi K3.1 Pro Together are neck and neck on quality (64.3 vs 60.5 on the BenchLeader Index, inside the ±4.5 margin). Choose GPT-5.5 for maths (70 vs 66) and reasoning (68 vs 67); choose Kimi K3.1 Pro Together for knowledge (68 vs 64).
Key facts (as of 9 Nov 2026)
- GPT-5.5 scores 64.3 on the BenchLeader Index and Kimi K3.1 Pro Together scores 60.5 (BenchLeader, 9 Nov 2026).
- GPT-5.5 costs $11.25 per 1M tokens blended (list price, 9 Nov 2026).
- Of the 5 benchmarks both models have, GPT-5.5 leads 5 (BenchLeader, 9 Nov 2026).
GPT-5.5 benchmarks 
Kimi K3.1 Pro Together benchmarks Which to pick for…
The pick's numbers come first. Category scores on the BenchLeader scale (50 is the average model, 15 points one standard deviation). High confidence means a lead of half a standard deviation or more; under one point is called either.
| Use case | Pick | Why | Confidence |
|---|---|---|---|
| Maths | GPT-5.5 | 70 vs 66 category score; FrontierMath Tiers 1–3 85.3% vs 78.3% | Medium |
| Reasoning | GPT-5.5 | 68 vs 67 category score; Chess Puzzles 63.0% vs 45.0% | Medium |
| Knowledge | Kimi K3.1 Pro Together | 68 vs 64 category score; SimpleQA Verified 62.2% vs 63.0% | Medium |
| High volume on a budget | Neither flagship | A smaller model is usually the better fit: Cheapest good LLMs, Fastest LLMs | – |
Key differences
- GPT-5.5 (xhigh) and Kimi K3.1 Pro Together (max) are neck and neck on quality (64.3 vs 60.5, within the ±4.5 margin).
- GPT-5.5 (xhigh) is stronger in agents & tools, coding, instruction following, long context, maths, multimodal, reasoning.
- Kimi K3.1 Pro Together (max) is stronger in knowledge.
At a glance
| Spec | GPT-5.5 | Kimi K3.1 Pro Together |
|---|---|---|
| Developer | OpenAI | Moonshot AI |
| Released | 23 Apr 2026 | 23 Oct 2026 |
| Context window (tokens) | 1,050,000 | – |
| Compared at | GPT-5.5 (xhigh) | Kimi K3.1 Pro Together (max) |
| Open weights | No | No |
| Price in / out / cached input per 1M | $5.00 / $30.00 / $0.500 | – |
Category by category
Category scores on the BenchLeader scale: 50 is the average evaluated model, 15 points is one standard deviation. A gap under one point is called level.
| Category | GPT-5.5 (xhigh) | Kimi K3.1 Pro Together (max) | Leader |
|---|---|---|---|
| Reasoning | 68.3 | 67.1 | GPT-5.5 |
| Coding | 61.0 | – | not comparable |
| Agents & tools | 61.8 | – | not comparable |
| Maths | 69.8 | 65.8 | GPT-5.5 |
| Knowledge | 64.0 | 67.6 | Kimi K3.1 Pro Together |
| Instruction following | 74.0 | – | not comparable |
| Multimodal | 62.3 | – | not comparable |
| Long context | 67.0 | – | not comparable |
On one chart
Each domain on the index's own scale, where 50 is an average model. Click a domain to see the benchmarks behind it. Pick up to 5 models from the list.
Not drawn, measured for fewer than two of these models: Coding, Agents & tools, Instruction following, Long context, Multimodal, Human preference.
Where sources disagree
Across the 5 benchmarks both have, GPT-5.5 leads 5, Kimi K3.1 Pro Together leads 0.
| Overall index | GPT-5.5 (xhigh) | Kimi K3.1 Pro Together (max) | Leader |
|---|---|---|---|
| BenchLeader Index | 64.3 | 60.5 | neck and neck |
Each publisher runs its own tasks, harnesses and effort settings, so their overall verdicts can differ; BenchLeader reconciles them on one scale. † measured at another effort setting of the same model (the publisher did not test the one compared here).
Price, speed and latency
List prices blended at three input tokens per output token. Per-task prices use the token counts on the methodology page. Cost, tokens and time per benchmark task are measured: Artificial Analysis’ averages over its whole Intelligence Index run.
| Measure | GPT-5.5 (xhigh) | Kimi K3.1 Pro Together (max) |
|---|---|---|
| Blended price per 1M tokens | $11.25 | – |
| Input / output per 1M | $5.00 / $30.00 | – / – |
| Cached input per 1M | $0.500 | – |
| Price per task: chat reply | $0.011 | – |
| Price per task: summarize a 30-page report | $0.078 | – |
| Price per task: code edit | $0.075 | – |
| Price per task: agentic coding session | $0.420 | – |
| Price per task: structured extraction | $0.016 | – |
| Agentic coding session, input mostly cached | $0.217 | – |
| Output speed | 80 tok/s | – |
| Time to first answer | 44.1 s | – |
| Time to a complete answer | 98.5 s | – |
Each model is compared at its best-ranked reasoning-effort setting. GPT-5.5 (xhigh) scores 64.3 and takes 44 s to its first answer token; GPT-5.5 (high) scores 63.7 in 23 s, GPT-5.5 scores 61.7 in 2 s. Kimi K3.1 Pro Together (max) scores 60.5. Higher effort means more thinking before the answer: better scores, longer waits and more tokens billed. How reasoning effort changes scores and cost.
Every benchmark
126 benchmarks, grouped by category; each name links to the board and its leaders. † measured at another effort setting of the same model, shown for reference and not counted as a win.
| Metric | Publisher | GPT-5.5 (xhigh) | Kimi K3.1 Pro Together (max) |
|---|---|---|---|
| BenchLeader Index | BenchLeader | 64.3 | 60.5 |
| Agents & tools score | BenchLeader | 61.8 | – |
| Coding score | BenchLeader | 61.0 | – |
| Instruction following score | BenchLeader | 74.0 | – |
| Knowledge score | BenchLeader | 64.0 | 67.6 |
| Long context score | BenchLeader | 67.0 | – |
| Maths score | BenchLeader | 69.8 | 65.8 |
| Multimodal score | BenchLeader | 62.3 | – |
| Reasoning score | BenchLeader | 68.3 | 67.1 |
| Blended price $/M | BenchLeader | $11.25 | – |
| Output speed | BenchLeader | 80 tok/s | – |
| Time to first answer | BenchLeader | 44.1 s | – |
| Context window | BenchLeader | 1,050,000 tokens | – |
| Reasoning | |||
| GPQA Diamond | Epoch AI Benchmarking Hub | 90.7%† | 94.2% |
| SimpleBench | SimpleBench | 69.0%† | – |
| Arena Hard Prompts | Arena (LMArena) | 1499† | – |
| LiveBench 1.0 Reasoning | LiveBench | 89.7% | – |
| GPQA Diamond (AA) | Artificial Analysis | 93.5% | – |
| Humanity's Last Exam (AA) | Artificial Analysis | 45.8% | – |
| GPQA Diamond (Vals) | Vals AI | 93.2% | – |
| Kagi LLM Benchmark | Kagi LLM Benchmark | 88.8%† | – |
| ARC-AGI-1 | ARC Prize | 95.0% | – |
| ARC-AGI-2 | ARC Prize | 85.0% | – |
| ARC-AGI-3 | ARC Prize | 0.4%† | – |
| CritPt | Artificial Analysis | 27.1% | – |
| Chess Puzzles | Epoch AI Benchmarking Hub | 63.0% | 45.0% |
| Mystery Game Puzzles | Epoch AI Benchmarking Hub | 56.0% | 42.0% |
| CL-bench Life | Epoch AI Benchmarking Hub | 22.2%† | – |
| LMCA | Epoch AI Benchmarking Hub | 54.3% | – |
| DTBench | Epoch AI Benchmarking Hub | 96.0% | – |
| ForecastBench | ForecastBench | 64.5%† | – |
| BTF-3 | Epoch AI Benchmarking Hub | 14.3%† | – |
| Coding | |||
| SciCode | SciCode | 55.8% | – |
| WeirdML | WeirdML | 84.9% | – |
| FrontierCode | Cognition | 43.0%† | – |
| GSO-Bench | GSO-Bench | 40.2% | – |
| Arena Coding | Arena (LMArena) | 1510† | – |
| Arena WebDev | Arena (LMArena) | 1512 | – |
Show all 126 benchmarks
| Metric | Publisher | GPT-5.5 (xhigh) | Kimi K3.1 Pro Together (max) |
|---|---|---|---|
| Coding | |||
| LiveBench 1.0 Coding | LiveBench | 82.2% | – |
| LiveCodeBench | Vals AI | 85.3% | – |
| SWE-bench (Vals) | Vals AI | 82.6% | – |
| Code Migration | Vals AI | 45.2% | – |
| ProgramBench | Vals AI | 0.5% | – |
| Vibe Code Bench v1.1 | Vals AI | 69.8% | – |
| SWE Atlas: Codebase QnA | Scale AI SEAL | 45.4% | – |
| SWE Atlas: Refactoring | Scale AI SEAL | 44.8% | – |
| SWE Atlas: Test Writing | Scale AI SEAL | 42.6% | – |
| MirrorCode | Epoch AI Benchmarking Hub | 10.0%† | – |
| Surface Evolver Bench | Epoch AI Benchmarking Hub | 88.1%† | – |
| DeepSWE v1.1 | Epoch AI Benchmarking Hub | 67.0% | – |
| ALE-Bench | Epoch AI Benchmarking Hub | 1943.0 | – |
| Terminal-Bench 4.0 (AA) | Artificial Analysis | 14.7% | – |
| Terminal-Bench 2.1 (AA) | Artificial Analysis | 84.3% | – |
| GameBench 2 Overall | DuelLab GameBench 2 | 49.0† | – |
| GameBench 2 by reasoning setting | DuelLab GameBench 2 | 59.7 | – |
| Design Arena Website | Design Arena | 1253† | – |
| Agents & tools | |||
| Terminal-Bench | Terminal-Bench | 84.7%† | – |
| OSWorld-Verified 2.0 | OSWorld | 13.0% | – |
| Remote Labor Index | Scale AI / CAIS | 6.3%† | – |
| APEX-Agents | Mercor | 55.1%† | – |
| LiveBench Agentic Coding | LiveBench | 54.0% | – |
| Terminal-Bench Hard | Artificial Analysis | 60.6% | – |
| τ²-Bench Telecom (AA) | Artificial Analysis | 93.9% | – |
| Terminal-Bench 2.1 (Vals) | Vals AI | 76.4%† | – |
| MCP Atlas | Scale AI SEAL | 75.3% | – |
| HiL-Bench | Scale AI SEAL | 39.7%† | – |
| τ³-bench Banking | τ²-bench | 44.6% | – |
| τ³-Banking (AA) | Artificial Analysis | 39.0% | – |
| ITBench SRE (AA) | Artificial Analysis | 45.8% | – |
| Analyst Agent (AA) | Artificial Analysis | 50.0% | – |
| APEX-Agents (AA) | Artificial Analysis | 37.7% | – |
| Finance Agent v2 | Vals AI | 51.8% | – |
| Harvey's Legal Agent Benchmark v1 | Vals AI | 3.8% | – |
| Legal Research Bench | Vals AI | 40.4% | – |
| SkillsBench | Vals AI | 62.2% | – |
| SREBench | Vals AI | 3.8% | – |
| Tax Agent Bench | Vals AI | 21.8% | – |
| Terminal-Bench 2.0 (Vals) | Vals AI | 73.2%† | – |
| Time Horizon Index: KSP | Vals AI | 8.3% | – |
| Arena Search | Arena (LMArena) | 1226† | – |
| DeepResearch Bench | DeepResearch Bench | 54.0%† | – |
| PostTrainBench | Epoch AI Benchmarking Hub | 27.2% | – |
| ExploitBench | Epoch AI Benchmarking Hub | 47.4%† | – |
| GBAEval | Epoch AI Benchmarking Hub | 53.2%† | – |
| Vending-Bench 2 | Andon Labs | 7523.8† | – |
| AutomationBench | Artificial Analysis | 47.3% | – |
| GDP.pdf (AA) | Artificial Analysis | 21.2% | – |
| EnterpriseOps-Gym | Artificial Analysis | 46.6% | – |
| AA-Briefcase v1.1 | Artificial Analysis | 1135 | – |
| Design Arena Agentic | Design Arena | 1108† | – |
| Maths | |||
| FrontierMath Tiers 1–3 | Epoch AI Benchmarking Hub | 85.3% | 78.3% |
| FrontierMath Tier 4 | Epoch AI Benchmarking Hub | 72.5% | 65.8% |
| OTIS Mock AIME | Epoch AI Benchmarking Hub | 84.4%† | 100.0% |
| ProofBench | Vals AI | 50.0% | – |
| LiveBench Mathematics | LiveBench | 95.9% | – |
| AIME 2026 | MathArena | 100.0% | – |
| HMMT February 2026 | MathArena | 98.5% | – |
| USAMO 2026 | MathArena | 98.2% | – |
| MathArena Apex | MathArena | 80.2% | – |
| Arena Maths | Arena (LMArena) | 1500† | – |
| Knowledge | |||
| SimpleQA Verified | Epoch AI Benchmarking Hub | 63.0% | 62.2% |
| LiveBench 1.0 Data Analysis | LiveBench | 81.6% | – |
| MMLU-Pro | Vals AI | 88.1% | – |
| LegalBench | Vals AI | 86.5% | – |
| CorpFin | Vals AI | 68.4% | – |
| TaxEval | Vals AI | 75.0% | – |
| CaseLaw v2 | Vals AI | 66.2% | – |
| Excel Modeling Benchmark | Vals AI | 64.5% | – |
| MedCode | Vals AI | 49.1% | – |
| MedScribe | Vals AI | 86.9% | – |
| Public Benefits Bench v1.1 | Vals AI | 60.9% | – |
| DrugDiscoveryBench | Scale AI SEAL | 51.6% | – |
| EBR-bench | Epoch AI Benchmarking Hub | 34.3% | – |
| GDP.pdf | Epoch AI Benchmarking Hub | 26.0% | – |
| Instruction following | |||
| LiveBench Language | LiveBench | 87.4% | – |
| LiveBench Instruction Following | LiveBench | 70.7% | – |
| IFBench | Artificial Analysis | 75.8% | – |
| Arena Instruction Following | Arena (LMArena) | 1475† | – |
| Human preference | |||
| Arena Text | Arena (LMArena) | 1476† | – |
| EQ-Bench 4 | EQ-Bench | 1295† | – |
| Arena Creative Writing | Arena (LMArena) | 1448† | – |
| Arena Multi-turn | Arena (LMArena) | 1484† | – |
| Arena Longer Queries | Arena (LMArena) | 1487† | – |
| Multimodal | |||
| Arena Vision | Arena (LMArena) | 1296† | – |
| MMMU-Pro | Artificial Analysis | 79.9% | – |
| MMMU-Pro (Vals) | Vals AI | 88.3% | – |
| MortgageTax | Vals AI | 68.8% | – |
| Blueprint-Bench 2 | Epoch AI Benchmarking Hub | 36.2%† | – |
| Code2Video-AA | Artificial Analysis | 1000 | – |
| Long context | |||
| AA-LCR v1.1 | Artificial Analysis | 84.3% | – |
| Arena Document | Arena (LMArena) | 1479† | – |
| MLCR | Artificial Analysis | 28.9% | – |
| Composite | |||
| Epoch Capabilities Index | Epoch AI Benchmarking Hub | 160.0† | – |
| LiveBench 1.0 | LiveBench | 80.2% | – |
| AA Intelligence Index v4.3.2 | Artificial Analysis | 38.4 | – |
| AA Progress Index v1 | Artificial Analysis | 320 | – |
| Vals RSI Index | Vals AI | 16.5% | – |
| Vals Multimodal Index | Vals AI | 68.1% | – |
| Safety & honesty | |||
| FORTRESS | Scale AI SEAL | 16.3% | – |
Data as of 2026-11-09. Best configuration of each model; every score links to its source on the model pages.
DuelLab GameBench 2, release gb2-20261103-eaea31df94e6 (https://benchmarks.duellab.org/releases/gb2-20261103-eaea31df94e6/), CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Scores mapped to BenchLeader model names; not endorsed by DuelLab.
What changed
- Kimi K3.1 Pro Together (max): first results.
- GPT-5.5 (xhigh): 1 score revision.
- GPT-5.5 (xhigh): 1 new result (AA Progress Index v1).
- GPT-5.5 (xhigh): cost per task moved from $2.63/M to $2.10/M (20% down).
- GPT-5.5 (xhigh): 1 new result (AA-Briefcase v1.1).
- GPT-5.5 (xhigh): 2 new results (Harvey's Legal Agent Benchmark v1, Vals RSI Index).
- GPT-5.5 (xhigh): 1 score revision.
- GPT-5.5 (xhigh): BenchLeader Index 65.1 → 64.6.
- GPT-5.5 (xhigh): 6 new results (USAMO 2026, AutomationBench, GDP.pdf (AA)…).
- GPT-5.5 (xhigh): 1 score revision.
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- GPT-5.4 vs Kimi K3.1 Pro Together
Rankings: Best LLM overall · Best LLM for agents · Best cheap LLMs
GPT-5.5 vs Kimi K3.1 Pro Together: questions
- Is GPT-5.5 better than Kimi K3.1 Pro Together?
- GPT-5.5 (xhigh) and Kimi K3.1 Pro Together (max) are neck and neck on quality (64.3 vs 60.5, within the ±4.5 margin). The BenchLeader Index combines every independent quality benchmark; the two are within the margin of error as of 9 Nov 2026, so check the category scores for your use.
- Do independent benchmarks agree on GPT-5.5 vs Kimi K3.1 Pro Together?
- Across the 5 benchmarks both have, GPT-5.5 leads 5, Kimi K3.1 Pro Together leads 0.
- When was Kimi K3.1 Pro Together released?
- Kimi K3.1 Pro Together was released on 23 Oct 2026.