# GPT-5.5 Pro vs GPT-5.6 Terra > Side-by-side benchmark comparison for GPT-5.5 Pro and GPT-5.6 Terra across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks. - Canonical page: https://benchlm.ai/compare/gpt-5-5-pro-vs-gpt-5-6-terra - Last updated: September 24, 2026 - Shared sourced benchmarks: 5 - HTML indexing: indexable - Ranking lane: BenchAlign v5.7 ## Quick Verdict Pick GPT-5.6 Terra if you want the stronger benchmark profile. GPT-5.5 Pro only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score. ## Summary - GPT-5.6 Terra leads overall 72.58 to 72.42. - The clearest category separation is in mathematics, where the averages are 70.1 for GPT-5.5 Pro and 96.8 for GPT-5.6 Terra. - The biggest single benchmark swing is FrontierMath v2 (Tiers 1-3) in Mathematics, with scores of 51.000% and 84.900%. - GPT-5.6 Terra is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use. - GPT-5.6 Terra also has the larger context window at 1.05M. ## Model Snapshot | Property | GPT-5.5 Pro | GPT-5.6 Terra | |----------|----------|----------| | Creator | OpenAI | OpenAI | | Type | Proprietary | Proprietary | | Reasoning | Reasoning | Reasoning | | Context | 1M | 1.05M | | Overall Score | 72.42 | 72.58 | | Benchmarks Covered | 8 | 32 | | Pricing (input/output) | $30.00 / $180.00 | $2.00 / $12.00 | ## Category Breakdown ### Agentic - Winner: Not comparable - GPT-5.5 Pro public-lane score: Coming soon - GPT-5.6 Terra public-lane score: 59.5 (Supported · #18/105) | Benchmark | GPT-5.5 Pro | GPT-5.6 Terra | Winner | |-----------|-----------|-----------|--------| | BrowseComp | 90.1% | 87.5% | GPT-5.5 Pro | | Terminal-Bench 3.0 | Coming soon | 20.8% | Coming soon | | Terminal-Bench 2.1 | Coming soon | 87.4% | Coming soon | | OSWorld 2.0 | Coming soon | 50.2% | Coming soon | | CyberGym | Coming soon | 81.8% | Coming soon | | ExploitGym | Coming soon | 23.2% | Coming soon | | Toolathlon | Coming soon | 53.1% | Coming soon | | Terminal-Bench 2.1 (Vals) | Coming soon | 77.5% | Coming soon | | ApprenticeBench | Coming soon | 16% | Coming soon | ### Coding - Winner: Not comparable - GPT-5.5 Pro public-lane score: Coming soon - GPT-5.6 Terra public-lane score: 64.7 (Supported · #8/135) | Benchmark | GPT-5.5 Pro | GPT-5.6 Terra | Winner | |-----------|-----------|-----------|--------| | SWE-bench Pro | Coming soon | 63.4% | Coming soon | | Terminal-Bench 2.1 | Coming soon | 87.4% | Coming soon | | DeepSWE | Coming soon | 69.6% | Coming soon | | FrontierCode 1.1 Extended | Coming soon | 55.8% | Coming soon | | cursorBench32 | Coming soon | 64.9% | Coming soon | | VulcanBench v3 | Coming soon | 87.0% | Coming soon | | LiveCodeBench (Vals) | Coming soon | 85.9% | Coming soon | | SWE-bench (Vals) | Coming soon | 95.4% | Coming soon | ### Reasoning - Winner: Not comparable - GPT-5.5 Pro public-lane score: 75 (Unranked · 3 rankable rows) - GPT-5.6 Terra public-lane score: 65.4 (#12/19) | Benchmark | GPT-5.5 Pro | GPT-5.6 Terra | Winner | |-----------|-----------|-----------|--------| | ARC-AGI-1 | 95.00% | Coming soon | Coming soon | | ARC-AGI-2 | 84.2% | 83.9% | GPT-5.5 Pro | | ARC-AGI-3 | Coming soon | 0.8% | Coming soon | ### Multimodal & Grounded - Winner: Not comparable - GPT-5.5 Pro public-lane score: Coming soon - GPT-5.6 Terra public-lane score: 77.2 (#16/50) | Benchmark | GPT-5.5 Pro | GPT-5.6 Terra | Winner | |-----------|-----------|-----------|--------| | MMMU-Pro | Coming soon | 80.7% | Coming soon | | MMMU-Pro w/ Python | Coming soon | 82% | Coming soon | ### Knowledge - Winner: Not comparable - GPT-5.5 Pro public-lane score: Coming soon - GPT-5.6 Terra public-lane score: 71.1 (Supported · #9/158) | Benchmark | GPT-5.5 Pro | GPT-5.6 Terra | Winner | |-----------|-----------|-----------|--------| | HLE | 57.2% | Coming soon | Coming soon | | HLE w/o tools | 43.1% | Coming soon | Coming soon | | GPQA | Coming soon | 92.9% | Coming soon | | GPQA-D | Coming soon | 92.9% | Coming soon | | HLE-Verified | Coming soon | 51.1% | Coming soon | | LABBench2 | Coming soon | 81.2% | Coming soon | | HealthBench Professional | Coming soon | 57.7% | Coming soon | | HealthBench Hard | Coming soon | 32.7% | Coming soon | | GPQA Diamond (Vals) | Coming soon | 90.9% | Coming soon | | MMLU-Pro (Vals) | Coming soon | 86.7% | Coming soon | ### Instruction Following - Winner: Not comparable - GPT-5.5 Pro public-lane score: Coming soon - GPT-5.6 Terra public-lane score: 85.7 (#35/124) ### Mathematics - Winner: Not comparable - GPT-5.5 Pro public-lane score: 70.1 (Unranked · 3 rankable rows) - GPT-5.6 Terra public-lane score: 96.8 (Unranked · 3 rankable rows) | Benchmark | GPT-5.5 Pro | GPT-5.6 Terra | Winner | |-----------|-----------|-----------|--------| | FrontierMath (legacy) | 52.4% | 84.9% | GPT-5.6 Terra | | FrontierMath v2 (Tiers 1-3) | 51.000% | 84.900% | GPT-5.6 Terra | | FrontierMath v2 (Tier 4) | 39.600% | 68.300% | GPT-5.6 Terra | ## FAQ ### Which is better overall, GPT-5.5 Pro or GPT-5.6 Terra? GPT-5.6 Terra is ahead overall on BenchLM right now. ### Where is the biggest gap between GPT-5.5 Pro and GPT-5.6 Terra? The widest category gap is in mathematics, where the averages are 70.1 for GPT-5.5 Pro and 96.8 for GPT-5.6 Terra. ### How many benchmarks does GPT-5.5 Pro cover on BenchLM? GPT-5.5 Pro currently has 8 sourced benchmark scores on BenchLM. ### How many benchmarks does GPT-5.6 Terra cover on BenchLM? GPT-5.6 Terra currently has 32 sourced benchmark scores on BenchLM. ## Related Comparisons - [GPT-5.5 Pro vs GPT-5.5](/compare/gpt-5-5-vs-gpt-5-5-pro) - [GPT-5.6 Terra vs GPT-5.5](/compare/gpt-5-5-vs-gpt-5-6-terra) - [GPT-5.5 Pro vs GPT-5.6 Sol](/compare/gpt-5-5-pro-vs-gpt-5-6-sol) - [GPT-5.6 Terra vs GPT-5.6 Sol](/compare/gpt-5-6-sol-vs-gpt-5-6-terra) ## Explore More - [GPT-5.5 Pro profile](/models/gpt-5-5-pro) - [GPT-5.6 Terra profile](/models/gpt-5-6-terra) - [Compare Pricing](/llm-pricing) - [Alternative Finder](/tools/alternative-finder) - [LLM Selector](/tools/llm-selector) - [Overall Rankings](/best/overall)