Model comparison
GPT-5.5 vs GPT-5.5 Pro
Head-to-head evidence from 7 shared benchmark results across 4 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Sibling matchup inside the GPT-5.5 family.
Public leaderboard positions: GPT-5.5 #9 (Estimated); GPT-5.5 Pro #38 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.5 and GPT-5.5 Pro share 7 comparable benchmark results. 3 of 8 categories are comparable. 50 results are unique to GPT-5.5; 0 to GPT-5.5 Pro.
Updated July 23, 2026- Shared results
- 7
- GPT-5.5 only
- 50
- GPT-5.5 Pro only
- 0
- Comparable categories
- 3 / 8
GPT-5.5 makes more sense if knowledge is the priority or you want the cheaper token bill, while GPT-5.5 Pro is the cleaner fit if agentic is the priority.
Confidence note. This is a partial-evidence comparison with 7 shared benchmark results across 4 evidence categories; 3 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
GPT-5.5 and GPT-5.5 Pro sit in the same GPT-5.5 family. This page is less about two unrelated model lineages and more about how the siblings trade off on benchmark shape, token costs, and practical limits like context window.
GPT-5.5 is clearly ahead on the BenchAlign aggregate, 73.51 to 63.69. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.5's sharpest advantage is in knowledge, where it averages 57.8 against 57.2. The single biggest benchmark swing on the page is BrowseComp, 84.4% to 90.1%. GPT-5.5 Pro does hit back in agentic, so the answer changes if that is the part of the workload you care about most.
GPT-5.5 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $5.00 input / $30.00 output per 1M tokens for GPT-5.5. That is roughly 6.0x on output cost alone.
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-5.5 | Δ | GPT-5.5 Pro |
|---|---|---|---|
| Agentic | GPT-5.581.6 | Margin→ 8.5 | GPT-5.5 Pro90.1 |
| Knowledge | GPT-5.557.8 | Margin← 0.6 | GPT-5.5 Pro57.2 |
| Math | GPT-5.547.6 | Margin→ 0.5 | GPT-5.5 Pro48.1 |
| Coding | GPT-5.558.6 | MarginNo overlap | GPT-5.5 ProNot measured |
| Reasoning | GPT-5.585.0 | MarginNo overlap | GPT-5.5 ProNot measured |
| Multimodal | GPT-5.570.4 | MarginNo overlap | GPT-5.5 ProNot measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
BrowseComp
AgenticA 84.4%B 90.1%Winner: GPT-5.5 ProΔ 5.7BrowseComp: GPT-5.5 scored 84.4%; GPT-5.5 Pro scored 90.1%. GPT-5.5 Pro wins this benchmark. - Source ↗
HLE
KnowledgeA 52.2%B 57.2%Winner: GPT-5.5 ProΔ 5HLE: GPT-5.5 scored 52.2%; GPT-5.5 Pro scored 57.2%. GPT-5.5 Pro wins this benchmark. - Source ↗
FrontierMath v2 (Tier 4)
MathA 35.400%B 39.600%Winner: GPT-5.5 ProΔ 4.2FrontierMath v2 (Tier 4): GPT-5.5 scored 35.400%; GPT-5.5 Pro scored 39.600%. GPT-5.5 Pro wins this benchmark. - Source ↗
FrontierMath v2 (Tiers 1-3)
MathA 51.700%B 51.000%Winner: GPT-5.5Δ 0.7FrontierMath v2 (Tiers 1-3): GPT-5.5 scored 51.700%; GPT-5.5 Pro scored 51.000%. GPT-5.5 wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.5 | GPT-5.5 Pro | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.5$5 input / $30 output | GPT-5.5 Pro$30 input / $180 output | GPT-5.5 has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.5Not available | GPT-5.5 ProNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.5Not available | GPT-5.5 ProNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.51M | GPT-5.5 Pro1M | Listed context windows are equal. |
Benchmark Deep Dive
AgenticGPT-5.5 Pro wins24 benchmarks
| Benchmark | GPT-5.5 | GPT-5.5 Pro | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 82% | — | Not comparable |
| CyberGymSource | 81.8% | — | Not comparable |
| BrowseCompSource | 84.4% | 90.1% | GPT-5.5 Pro leads |
| OSWorld-VerifiedSource | 78.7% | — | Not comparable |
| MCP AtlasSource | 75.3% | — | Not comparable |
| ToolathlonSource | 55.6% | — | Not comparable |
| τ²-bench resultsSource | 93.9% | — | Not comparable |
| AA Agentic IndexSource | 44.9% | — | Not comparable |
| APEX-Agents-AASource | 37.7% | — | Not comparable |
| GDPval-AASource | 49.5% | — | Not comparable |
| GDPval-AASource | 1490 | — | Not comparable |
| Gert LabsSource | 72.93% | — | Not comparable |
| ResearchClawBenchSource | 17.0% | — | Not comparable |
| OSWorld 2.0Source | 13.0% | — | Not comparable |
| JobBenchSource | 42.7% | — | Not comparable |
| ExploitGymSource | 13.4% | — | Not comparable |
| AA BriefcaseSource | 1154 | — | Not comparable |
| AA AutomationBenchSource | 42.1% | — | Not comparable |
| AA EnterpriseOps-GymSource | 46.6% | — | Not comparable |
| AA Harvey LABSource | 86.3% | — | Not comparable |
| AA ITBenchSource | 45.8% | — | Not comparable |
| AA Tau3 BankingSource | 31.3% | — | Not comparable |
| terminalBenchHardSource | 60.6% | — | Not comparable |
| aaTerminalBench21Source | 84.3% | — | Not comparable |
Coding9 benchmarks
| Benchmark | GPT-5.5 | GPT-5.5 Pro | Result |
|---|---|---|---|
| SWE-bench ProSource | 58.6% | — | Not comparable |
| Terminal-Bench 2.0Source | 82.0% | — | Not comparable |
| Vibe Code BenchSource | 69.85% | — | Not comparable |
| React Native EvalsSource | 84.7% | — | Not comparable |
| cursorBench31Source | 59.2% | — | Not comparable |
| cursorBench32Source | 58.4% | — | Not comparable |
| AA Coding IndexSource | 74.9% | — | Not comparable |
| AA-SciCodeSource | 56.1% | — | Not comparable |
| FrontierCode 1.1 MainSource | 43.0% | — | Not comparable |
Reasoning5 benchmarks
KnowledgeGPT-5.5 wins10 benchmarks
| Benchmark | GPT-5.5 | GPT-5.5 Pro | Result |
|---|---|---|---|
| GPQASource | 93.6% | — | Not comparable |
| GPQA-DSource | 93.6% | — | Not comparable |
| HLESource | 52.2% | 57.2% | GPT-5.5 Pro leads |
| HLE w/o toolsSource | 41.4% | 43.1% | GPT-5.5 Pro leads |
| Artificial Analysis Intelligence IndexSource | 54.8% | — | Not comparable |
| AA-GPQA DiamondSource | 93.5% | — | Not comparable |
| AA-HLESource | 44.3% | — | Not comparable |
| AA-Omniscience IndexSource | 20.1% | — | Not comparable |
| AA-Omniscience AccuracySource | 56.9% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 85.5% | — | Not comparable |
MathGPT-5.5 Pro wins3 benchmarks
Multimodal5 benchmarks
Inst. Following1 benchmarks
| Benchmark | GPT-5.5 | GPT-5.5 Pro | Result |
|---|---|---|---|
| AA-IFBenchSource | 75.9% | — | Not comparable |
Frequently Asked Questions (4)
Which is better, GPT-5.5 or GPT-5.5 Pro?
GPT-5.5 and GPT-5.5 Pro are sibling variants in the GPT-5.5 family, so the right pick depends on whether you value the better benchmark line, cheaper tokens, or the larger context window. GPT-5.5 is ahead on BenchLM's BenchAlign leaderboard 73.51 to 63.69.
Which is better for knowledge tasks, GPT-5.5 or GPT-5.5 Pro?
GPT-5.5 has the edge for knowledge tasks in this comparison, averaging 57.8 versus 57.2. Inside this category, HLE is the benchmark that creates the most daylight between them.
Which is better for math, GPT-5.5 or GPT-5.5 Pro?
GPT-5.5 Pro has the edge for math in this comparison, averaging 48.1 versus 47.6. Inside this category, FrontierMath v2 (Tier 4) is the benchmark that creates the most daylight between them.
Which is better for agentic tasks, GPT-5.5 or GPT-5.5 Pro?
GPT-5.5 Pro has the edge for agentic tasks in this comparison, averaging 90.1 versus 81.6. Inside this category, BrowseComp is the benchmark that creates the most daylight between them.
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