Model comparison
GPT-5.5 Pro vs Grok 4.5
Head-to-head evidence from 1 shared benchmark result across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.5 Pro #38 (Estimated); Grok 4.5 #7 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.5 Pro and Grok 4.5 share 1 comparable benchmark result. 1 of 8 categories are comparable. 6 results are unique to GPT-5.5 Pro; 27 to Grok 4.5.
Updated July 23, 2026- Shared results
- 1
- GPT-5.5 Pro only
- 6
- Grok 4.5 only
- 27
- Comparable categories
- 1 / 8
Pick Grok 4.5 if you want the stronger benchmark profile. GPT-5.5 Pro only becomes the better choice if agentic is the priority or you need the larger 1M context window.
Confidence note. This is a partial-evidence comparison with 1 shared benchmark result across 1 evidence category; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Grok 4.5 is clearly ahead on the BenchAlign aggregate, 76.72 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 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $2.00 input / $6.00 output per 1M tokens for Grok 4.5. That is roughly 30.0x on output cost alone. GPT-5.5 Pro gives you the larger context window at 1M, compared with 500K for Grok 4.5.
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 Pro | Δ | Grok 4.5 |
|---|---|---|---|
| Agentic | GPT-5.5 Pro90.1 | Margin← 6.8 | Grok 4.583.3 |
| Coding | GPT-5.5 ProNot measured | MarginNo overlap | Grok 4.564.7 |
| Knowledge | GPT-5.5 Pro57.2 | MarginNo overlap | Grok 4.5Not measured |
| Math | GPT-5.5 Pro48.1 | MarginNo overlap | Grok 4.5Not measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.5 Pro | Grok 4.5 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.5 Pro$30 input / $180 output | Grok 4.5$2 input / $6 output | Grok 4.5 has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.5 ProNot available | Grok 4.5Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.5 ProNot available | Grok 4.5Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.5 Pro1M | Grok 4.5500K | GPT-5.5 Pro lists the larger context window. |
Benchmark Deep Dive
AgenticGPT-5.5 Pro wins12 benchmarks
| Benchmark | GPT-5.5 Pro | Grok 4.5 | Result |
|---|---|---|---|
| BrowseCompSource | 90.1% | — | Not comparable |
| Terminal-Bench 2.0Source | — | 83.3% | Not comparable |
| deepSweSource | — | 53% | Not comparable |
| AA Agentic IndexSource | — | 45.7% | Not comparable |
| GDPval-AASource | — | 51.7% | Not comparable |
| GDPval-AASource | — | 1535 | Not comparable |
| AA BriefcaseSource | — | 1323 | Not comparable |
| AA AutomationBenchSource | — | 51.4% | Not comparable |
| AA EnterpriseOps-GymSource | — | 40.8% | Not comparable |
| AA Harvey LABSource | — | 92.4% | Not comparable |
| AA Tau3 BankingSource | — | 32.6% | Not comparable |
| aaTerminalBench21Source | — | 81.6% | Not comparable |
Coding7 benchmarks
| Benchmark | GPT-5.5 Pro | Grok 4.5 | Result |
|---|---|---|---|
| SWE-bench ProSource | — | 64.7% | Not comparable |
| SWE MultilingualSource | — | 78% | Not comparable |
| Terminal-Bench 2.0Source | — | 83.3% | Not comparable |
| cursorBench32Source | — | 66.7% | Not comparable |
| VulcanBench v3Source | — | 91.3% | Not comparable |
| AA Coding IndexSource | — | 72.5% | Not comparable |
| AA-SciCodeSource | — | 54.1% | Not comparable |
Reasoning2 benchmarks
Knowledge8 benchmarks
| Benchmark | GPT-5.5 Pro | Grok 4.5 | Result |
|---|---|---|---|
| HLESource | 57.2% | — | Not comparable |
| HLE w/o toolsSource | 43.1% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 53.8% | Not comparable |
| AA-GPQA DiamondSource | — | 93.1% | Not comparable |
| AA-HLESource | — | 40.3% | Not comparable |
| AA-Omniscience IndexSource | — | 26.4% | Not comparable |
| AA-Omniscience AccuracySource | — | 52.1% | Not comparable |
| AA-Omniscience Hallucination RateSource | — | 53.5% | Not comparable |
Math3 benchmarks
Frequently Asked Questions (2)
Which is better, GPT-5.5 Pro or Grok 4.5?
Grok 4.5 is ahead on BenchLM's BenchAlign leaderboard, 76.72 to 63.69.
Which is better for agentic tasks, GPT-5.5 Pro or Grok 4.5?
GPT-5.5 Pro has the edge for agentic tasks in this comparison, averaging 90.1 versus 83.3. Grok 4.5 stays close enough that the answer can still flip depending on your workload.
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