Model comparison
GPT-5.6 Terra vs o3
Head-to-head evidence from 15 shared benchmark results across 7 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.6 Terra #10 (Estimated); o3 #129 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.6 Terra and o3 share 15 comparable benchmark results. 1 of 8 categories are comparable. 28 results are unique to GPT-5.6 Terra; 2 to o3.
Updated July 17, 2026- Shared results
- 15
- GPT-5.6 Terra only
- 28
- o3 only
- 2
- Comparable categories
- 1 / 8
Pick GPT-5.6 Terra if you want the stronger benchmark profile. o3 only becomes the better choice if you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 15 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, 72.58 to 47.84. 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 14.5. The single biggest benchmark swing on the page is FrontierMath v2 (Tier 4), 68.300% to 2.083%.
GPT-5.6 Terra is also the more expensive model on tokens at $2.50 input / $15.00 output per 1M tokens, versus $2.00 input / $8.00 output per 1M tokens for o3. GPT-5.6 Terra gives you the larger context window at 1M, compared with 200K for o3.
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-5.6 Terra | Δ | o3 |
|---|---|---|---|
| Math | GPT-5.6 Terra80.8 | Margin← 66.3 | o314.5 |
| Agentic | GPT-5.6 Terra87.4 | MarginNo overlap | o3Not measured |
| Coding | GPT-5.6 Terra63.4 | MarginNo overlap | o3Not measured |
| Knowledge | GPT-5.6 Terra92.9 | MarginNo overlap | o3Not measured |
| Multimodal | GPT-5.6 Terra80.7 | MarginNo overlap | o3Not measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
FrontierMath v2 (Tier 4)
MathA 68.300%B 2.083%Winner: GPT-5.6 TerraΔ 66.2FrontierMath v2 (Tier 4): GPT-5.6 Terra scored 68.300%; o3 scored 2.083%. GPT-5.6 Terra wins this benchmark. - Source ↗
FrontierMath v2 (Tiers 1-3)
MathA 84.900%B 18.685%Winner: GPT-5.6 TerraΔ 66.2FrontierMath v2 (Tiers 1-3): GPT-5.6 Terra scored 84.900%; o3 scored 18.685%. 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-5.6 Terra | o3 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.6 Terra$2.5 input / $15 output | o3$2 input / $8 output | o3 has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.6 TerraNot available | o3118 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.6 TerraNot available | o35.38 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.6 Terra1M | o3200K | GPT-5.6 Terra lists the larger context window. |
Benchmark Deep Dive
Agentic14 benchmarks
| Benchmark | GPT-5.6 Terra | o3 | Result |
|---|---|---|---|
| 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 Agentic IndexSource | 47.4% | — | Not comparable |
| τ²-bench resultsSource | 86.3% | 80.7% | GPT-5.6 Terra leads |
| GDPval-AASource | 54.6% | — | Not comparable |
| GDPval-AASource | 1593 | — | Not comparable |
| AA Harvey LABSource | 2.5% | — | Not comparable |
| AA ITBenchSource | 51.0% | — | Not comparable |
| AA Tau3 BankingSource | 31.8% | — | Not comparable |
| AA AutomationBenchSource | 45.6% | — | Not comparable |
Coding9 benchmarks
| Benchmark | GPT-5.6 Terra | o3 | Result |
|---|---|---|---|
| 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 |
| AA Coding IndexSource | 76.7% | — | Not comparable |
| Terminal-Bench HardSource | 57.6% | 37.1% | GPT-5.6 Terra leads |
| AA-SciCodeSource | 53.9% | 41.0% | GPT-5.6 Terra leads |
| AA Terminal-Bench 2.1Source | 88.0% | — | Not comparable |
Reasoning3 benchmarks
Knowledge10 benchmarks
| Benchmark | GPT-5.6 Terra | o3 | Result |
|---|---|---|---|
| GPQASource | 92.9% | — | Not comparable |
| GPQA-DSource | 92.9% | — | Not comparable |
| HealthBench ProfessionalSource | 57.7% | — | Not comparable |
| HealthBench HardSource | 32.7% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 55.0% | 30.4% | GPT-5.6 Terra leads |
| AA-GPQA DiamondSource | 92.5% | 82.7% | GPT-5.6 Terra leads |
| AA-HLESource | 41.8% | 20.0% | GPT-5.6 Terra leads |
| AA-Omniscience IndexSource | -0.2% | -15.3% | GPT-5.6 Terra leads |
| AA-Omniscience AccuracySource | 45.9% | 38.4% | GPT-5.6 Terra leads |
| AA-Omniscience Hallucination RateSource | 85.2% | 87.1% | GPT-5.6 Terra leads |
MathGPT-5.6 Terra wins4 benchmarks
Multimodal4 benchmarks
Inst. Following1 benchmarks
| Benchmark | GPT-5.6 Terra | o3 | Result |
|---|---|---|---|
| AA-IFBenchSource | 71.2% | 71.4% | o3 leads |
Frequently Asked Questions (2)
Which is better, GPT-5.6 Terra or o3?
GPT-5.6 Terra is ahead on BenchLM's BenchAlign leaderboard, 72.58 to 47.84. The biggest single separator in this matchup is FrontierMath v2 (Tier 4), where the scores are 68.300% and 2.083%.
Which is better for math, GPT-5.6 Terra or o3?
GPT-5.6 Terra has the edge for math in this comparison, averaging 80.8 versus 14.5. Inside this category, FrontierMath v2 (Tier 4) is the benchmark that creates the most daylight between them.
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