GPT-5.5 Pro vs GPT-6.1 Terra
Full profiles: GPT-5.5 Pro (OpenAI) and GPT-6.1 Terra (OpenAI): every benchmark, price and rank.
Updated · Data from 5 sources
As of 27 Oct 2026, GPT-5.5 Pro (xhigh) and GPT-6.1 Terra (max) are neck and neck on quality (65.2 vs 65.9 on the BenchLeader Index, inside the ±10.6 margin of error), and GPT-6.1 Terra (max) costs 34× less, which makes it the better buy for most workloads. GPT-6.1 Terra leads in every category we measure both in.
GPT-5.5 Pro 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 |
|---|---|---|---|
| Reasoning | GPT-6.1 Terra | 86 vs 77 category score; CritPt 28.0% vs 30.6% | High |
| Lowest cost | GPT-6.1 Terra | $2.00 vs $67.50 per 1M blended; agentic coding session $0.080 vs $2.52 | – |
| Fastest first answer | GPT-5.5 Pro | 5.5 s (GPT-5.5 Pro (xhigh)) vs 131.8 s (GPT-6.1 Terra (max)) to the first answer token | – |
| 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 Pro (xhigh) and GPT-6.1 Terra (max) are neck and neck on quality (65.2 vs 65.9, within the ±10.6 margin).
- GPT-5.5 Pro (xhigh) is stronger in maths.
- GPT-6.1 Terra (max) is stronger in reasoning, composite, knowledge, long context, multimodal.
- GPT-6.1 Terra (max) is 34× cheaper ($2.00 vs $67.50 per 1M blended).
- GPT-6.1 Terra (max) streams 3.4× faster (91 vs 27 tokens per second).
At a glance
| Spec | GPT-5.5 Pro | GPT-6.1 Terra |
|---|---|---|
| Developer | OpenAI | OpenAI |
| Released | 23 Apr 2026 | 26 Oct 2026 |
| Context window (tokens) | 1,050,000 | 1,050,000 |
| Compared at | GPT-5.5 Pro (xhigh) | GPT-6.1 Terra (max) |
| Open weights | No | No |
| Price in / out / cached input per 1M | $30.00 / $180.00 / – | $1.00 / $5.00 / $0.050 |
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 Pro (xhigh) | GPT-6.1 Terra (max) | Leader |
|---|---|---|---|
| Reasoning | 77.3 | 86.2 | GPT-6.1 Terra |
| Maths | 71.3 | – | not comparable |
| Knowledge | – | 74.5 | not comparable |
| Multimodal | – | 67.5 | not comparable |
| Long context | – | 66.3 | not comparable |
| Composite | – | 82.8 | not comparable |
Where sources disagree
Across the 1 benchmarks both have, GPT-5.5 Pro leads 1, GPT-6.1 Terra leads 0.
| Overall index | GPT-5.5 Pro (xhigh) | GPT-6.1 Terra (max) | Leader |
|---|---|---|---|
| BenchLeader Index | 65.2 | 65.9 | 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; suite cost is what Artificial Analysis paid to run its whole Intelligence Index.
| Measure | GPT-5.5 Pro (xhigh) | GPT-6.1 Terra (max) |
|---|---|---|
| Blended price per 1M tokens | $67.50 | $2.00 |
| Input / output per 1M | $30.00 / $180.00 | $1.00 / $5.00 |
| Cached input per 1M | – | $0.050 |
| Price per task: chat reply | $0.066 | $0.0019 |
| Price per task: summarize a 30-page report | $0.468 | $0.015 |
| Price per task: code edit | $0.450 | $0.013 |
| Price per task: agentic coding session | $2.52 | $0.080 |
| Price per task: structured extraction | $0.096 | $0.0030 |
| Cost to run a full benchmark suite | – | $0.403 |
| Output speed | 27 tok/s | 91 tok/s |
| Time to first answer | 5.5 s | 131.8 s |
| Time to a complete answer | – | 137.3 s |
Each model is compared at its best-ranked reasoning-effort setting. GPT-5.5 Pro (xhigh) scores 65.2 and takes 5 s to its first answer token. GPT-6.1 Terra (max) scores 65.9 and takes 132 s to its first answer token; GPT-6.1 Terra (xhigh) scores 65.0 in 18 s, GPT-6.1 Terra (high) scores 64.7 in 7 s. 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
33 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 Pro (xhigh) | GPT-6.1 Terra (max) |
|---|---|---|---|
| BenchLeader Index | BenchLeader | 65.2 | 65.9 |
| Maths score | BenchLeader | 71.3 | – |
| Reasoning score | BenchLeader | 77.3 | 86.2 |
| Composite score | BenchLeader | – | 82.8 |
| Knowledge score | BenchLeader | – | 74.5 |
| Long context score | BenchLeader | – | 66.3 |
| Multimodal score | BenchLeader | – | 67.5 |
| Blended price $/M | BenchLeader | $67.50 | $2.00 |
| Output speed | BenchLeader | 27 tok/s | 91 tok/s |
| Time to first answer | BenchLeader | 5.5 s | 131.8 s |
| Context window | BenchLeader | 1,050,000 tokens | 1,050,000 tokens |
| Reasoning | |||
| SimpleBench | SimpleBench | 76.9%† | – |
| LiveBench 2.0 Reasoning | LiveBench | – | 88.7%† |
| Humanity's Last Exam (AA) | Artificial Analysis | – | 46.3% |
| ARC-AGI-1 | ARC Prize | 95.0% | – |
| ARC-AGI-2 | ARC Prize | 84.2% | – |
| CritPt | Artificial Analysis | 30.6% | 28.0% |
| Chess Puzzles | Epoch AI Benchmarking Hub | 62.0% | – |
| LMCA | Epoch AI Benchmarking Hub | 53.9% | – |
| DTBench | Epoch AI Benchmarking Hub | 96.0% | – |
| Coding | |||
| LiveBench 2.0 Coding | LiveBench | – | 90.8%† |
| SciCode (AA) | Artificial Analysis | – | 55.1% |
| Terminal-Bench 4.0 (AA) | Artificial Analysis | – | 55.6% |
| FrontierCode 1.1 (AA) | Artificial Analysis | – | 36.0% |
| Agents & tools | |||
| LiveBench Long Agentic | LiveBench | – | 48.6%† |
| LiveBench Browser | LiveBench | – | 93.1%† |
| AutomationBench | Artificial Analysis | – | 60.2% |
| GDP.pdf (AA) | Artificial Analysis | – | 28.6% |
| AA-Briefcase v1.1 | Artificial Analysis | – | 1402 |
| Terminal-Bench-Science 0.1 (AA) | Artificial Analysis | – | 57.6% |
| Maths | |||
| FrontierMath Tiers 1–3 | Epoch AI Benchmarking Hub | 87.7% | – |
| FrontierMath Tier 4 | Epoch AI Benchmarking Hub | 78.0% | – |
| Knowledge | |||
| LiveBench 2.0 Data Analysis | LiveBench | – | 82.3%† |
| LiveBench Research | LiveBench | – | 73.9%† |
| AA-Omniscience | Artificial Analysis | – | 29.8 |
| AA-Omniscience: accuracy | Artificial Analysis | – | 49.1% |
Show all 33 benchmarks
| Metric | Publisher | GPT-5.5 Pro (xhigh) | GPT-6.1 Terra (max) |
|---|---|---|---|
| Knowledge | |||
| AA-Omniscience: non-hallucination | Artificial Analysis | – | 62.0% |
| Multimodal | |||
| LiveBench Design | LiveBench | – | 82.3%† |
| MMMU-Pro | Artificial Analysis | – | 84.7% |
| Long context | |||
| AA-LCR | Artificial Analysis | – | 82.7% |
| Composite | |||
| Epoch Capabilities Index | Epoch AI Benchmarking Hub | 162.9† | – |
| LiveBench 2.0 | LiveBench | – | 77.2%† |
| AA Intelligence Index v4.3.2 | Artificial Analysis | – | 48.1 |
| Safety & honesty | |||
| FORTRESS | Scale AI SEAL | – | 18.2%† |
Data as of 2026-10-27. Best configuration of each model; every score links to its source on the model pages.
What changed
- GPT-5.5 Pro (xhigh): 1 new result (Chess Puzzles).
- GPT-5.5 Pro (xhigh): BenchLeader Index 66.5 → 65.6.
- GPT-5.5 Pro (xhigh): BenchLeader Index 67.1 → 66.5.
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Rankings: Best LLM overall · Best LLM for agents · Best cheap LLMs
GPT-5.5 Pro vs GPT-6.1 Terra: questions
- Is GPT-5.5 Pro better than GPT-6.1 Terra?
- GPT-5.5 Pro (xhigh) and GPT-6.1 Terra (max) are neck and neck on quality (65.2 vs 65.9, within the ±10.6 margin). The BenchLeader Index combines every independent quality benchmark; the two are within the margin of error as of 2026-10-27, so check the category scores for your use.
- Which is cheaper, GPT-5.5 Pro or GPT-6.1 Terra, and will that change?
- GPT-6.1 Terra is cheaper today: $2.00 against $67.50 per million tokens, blended at three input tokens per output token. No price change has been announced for either.
- Which is better for long documents?
- Both accept 1,050,000 tokens of context.
- Which has lower latency?
- GPT-5.5 Pro (xhigh) answers first: 5.5 s against 131.8 s to the first answer token, as Artificial Analysis measures it. Reasoning effort drives most of this: a higher setting thinks longer before it answers.
- Which is faster, GPT-5.5 Pro or GPT-6.1 Terra?
- GPT-6.1 Terra streams faster: 91 against 27 output tokens per second.
- Do independent benchmarks agree on GPT-5.5 Pro vs GPT-6.1 Terra?
- Across the 1 benchmarks both have, GPT-5.5 Pro leads 1, GPT-6.1 Terra leads 0.
- When was GPT-6.1 Terra released?
- GPT-6.1 Terra was released on 26 Oct 2026.