Model comparison
GPT-5.1 vs GPT-5.6 Terra
Head-to-head evidence from 18 shared benchmark results across 7 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.1 #94 (Estimated); GPT-5.6 Terra #11 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.1 and GPT-5.6 Terra share 18 comparable benchmark results. 1 of 8 categories are comparable. 3 results are unique to GPT-5.1; 26 to GPT-5.6 Terra.
Updated July 23, 2026- Shared results
- 18
- GPT-5.1 only
- 3
- GPT-5.6 Terra only
- 26
- Comparable categories
- 1 / 8
Pick GPT-5.6 Terra if you want the stronger benchmark profile. GPT-5.1 only becomes the better choice if you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 18 shared benchmark results across 7 evidence categories; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
GPT-5.6 Terra is clearly ahead on the BenchAlign aggregate, 72.57 to 53.65. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.6 Terra's sharpest advantage is in mathematics, where it averages 80.8 against 26.4. The single biggest benchmark swing on the page is FrontierMath v2 (Tier 4), 12.500% to 68.300%.
GPT-5.6 Terra is also the more expensive model on tokens at $2.50 input / $15.00 output per 1M tokens, versus $1.25 input / $10.00 output per 1M tokens for GPT-5.1. GPT-5.6 Terra gives you the larger context window at 1M, compared with 200K for GPT-5.1.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | GPT-5.1 | Δ | GPT-5.6 Terra |
|---|---|---|---|
| Math | GPT-5.126.4 | Margin→ 54.4 | GPT-5.6 Terra80.8 |
| Agentic | GPT-5.1Not measured | MarginNo overlap | GPT-5.6 Terra87.4 |
| Coding | GPT-5.1Not measured | MarginNo overlap | GPT-5.6 Terra63.4 |
| Knowledge | GPT-5.1Not measured | MarginNo overlap | GPT-5.6 Terra92.9 |
| Multimodal | GPT-5.1Not measured | MarginNo overlap | GPT-5.6 Terra80.7 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
FrontierMath v2 (Tier 4)
MathA 12.500%B 68.300%Winner: GPT-5.6 TerraΔ 55.8FrontierMath v2 (Tier 4): GPT-5.1 scored 12.500%; GPT-5.6 Terra scored 68.300%. GPT-5.6 Terra wins this benchmark. - Source ↗
FrontierMath v2 (Tiers 1-3)
MathA 31.034%B 84.900%Winner: GPT-5.6 TerraΔ 53.9FrontierMath v2 (Tiers 1-3): GPT-5.1 scored 31.034%; GPT-5.6 Terra scored 84.900%. GPT-5.6 Terra wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.1 | GPT-5.6 Terra | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.1$1.25 input / $10 output | GPT-5.6 Terra$2.5 input / $15 output | GPT-5.1 has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.1111 tok/s | GPT-5.6 TerraNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.157.47 s | GPT-5.6 TerraNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.1200K | GPT-5.6 Terra1M | GPT-5.6 Terra lists the larger context window. |
Benchmark Deep Dive
Agentic18 benchmarks
| Benchmark | GPT-5.1 | GPT-5.6 Terra | Result |
|---|---|---|---|
| AA Agentic IndexSource | 21.0% | 47.4% | GPT-5.6 Terra leads |
| τ²-bench resultsSource | 81.9% | 86.3% | GPT-5.6 Terra leads |
| Gert LabsSource | 41.24% | — | Not comparable |
| GDPval-AASource | 24.4% | 54.1% | GPT-5.6 Terra leads |
| GDPval-AASource | 987 | 1581 | GPT-5.6 Terra leads |
| Terminal-Bench 2.0Source | — | 87.4% | Not comparable |
| BrowseCompSource | — | 87.5% | Not comparable |
| OSWorld 2.0Source | — | 50.2% | Not comparable |
| CyberGymSource | — | 81.8% | Not comparable |
| ExploitGymSource | — | 23.2% | Not comparable |
| ToolathlonSource | — | 53.1% | Not comparable |
| AA Harvey LABSource | — | 85.2% | Not comparable |
| AA ITBenchSource | — | 51.0% | Not comparable |
| AA Tau3 BankingSource | — | 31.8% | Not comparable |
| AA AutomationBenchSource | — | 45.6% | Not comparable |
| terminalBenchHardSource | — | 57.6% | Not comparable |
| aaTerminalBench21Source | — | 88% | Not comparable |
| APEX-Agents-AASource | — | 38.9% | Not comparable |
Coding8 benchmarks
| Benchmark | GPT-5.1 | GPT-5.6 Terra | Result |
|---|---|---|---|
| Vibe Code BenchSource | 24.61% | — | Not comparable |
| AA Coding IndexSource | 49.4% | 76.7% | GPT-5.6 Terra leads |
| AA-SciCodeSource | 43.3% | 53.9% | GPT-5.6 Terra leads |
| SWE-bench ProSource | — | 63.4% | Not comparable |
| Terminal-Bench 2.0Source | — | 87.4% | Not comparable |
| deepSweSource | — | 69.6% | Not comparable |
| FrontierCode 1.1 ExtendedSource | — | 55.8% | Not comparable |
| cursorBench32Source | — | 64.9% | Not comparable |
Reasoning3 benchmarks
Knowledge10 benchmarks
| Benchmark | GPT-5.1 | GPT-5.6 Terra | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 36.9% | 55.0% | GPT-5.6 Terra leads |
| AA-GPQA DiamondSource | 87.3% | 92.5% | GPT-5.6 Terra leads |
| AA-HLESource | 26.5% | 41.8% | GPT-5.6 Terra leads |
| AA-Omniscience IndexSource | 5.6% | -0.2% | GPT-5.1 leads |
| AA-Omniscience AccuracySource | 37.6% | 45.9% | GPT-5.6 Terra leads |
| AA-Omniscience Hallucination RateSource | 51.3% | 85.2% | GPT-5.1 leads |
| GPQASource | — | 92.9% | Not comparable |
| GPQA-DSource | — | 92.9% | Not comparable |
| HealthBench ProfessionalSource | — | 57.7% | Not comparable |
| HealthBench HardSource | — | 32.7% | Not comparable |
MathGPT-5.6 Terra wins3 benchmarks
Multimodal4 benchmarks
Inst. Following1 benchmarks
| Benchmark | GPT-5.1 | GPT-5.6 Terra | Result |
|---|---|---|---|
| AA-IFBenchSource | 72.9% | 71.2% | GPT-5.1 leads |
Frequently Asked Questions (2)
Which is better, GPT-5.1 or GPT-5.6 Terra?
GPT-5.6 Terra is ahead on BenchLM's BenchAlign leaderboard, 72.57 to 53.65. The biggest single separator in this matchup is FrontierMath v2 (Tier 4), where the scores are 12.500% and 68.300%.
Which is better for math, GPT-5.1 or GPT-5.6 Terra?
GPT-5.6 Terra has the edge for math in this comparison, averaging 80.8 versus 26.4. Inside this category, FrontierMath v2 (Tier 4) is the benchmark that creates the most daylight between them.
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