Model comparison
Claude 3.5 Sonnet vs GPT-5.1
Head-to-head evidence from 2 shared benchmark results across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude 3.5 Sonnet #132 (Estimated); GPT-5.1 #94 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude 3.5 Sonnet and GPT-5.1 share 2 comparable benchmark results. 1 of 8 categories are comparable. 2 results are unique to Claude 3.5 Sonnet; 19 to GPT-5.1.
Updated July 20, 2026- Shared results
- 2
- Claude 3.5 Sonnet only
- 2
- GPT-5.1 only
- 19
- Comparable categories
- 1 / 8
Pick GPT-5.1 if you want the stronger benchmark profile. Claude 3.5 Sonnet only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.
Confidence note. This is a partial-evidence comparison with 2 shared benchmark results 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
GPT-5.1 is clearly ahead on the BenchAlign aggregate, 53.65 to 47.74. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.1's sharpest advantage is in mathematics, where it averages 26.4 against 1.6. The single biggest benchmark swing on the page is FrontierMath v2 (Tiers 1-3), 2.069% to 31.034%.
Claude 3.5 Sonnet is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $1.25 input / $10.00 output per 1M tokens for GPT-5.1. GPT-5.1 is the reasoning model in the pair, while Claude 3.5 Sonnet is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use.
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 | Claude 3.5 Sonnet | Δ | GPT-5.1 |
|---|---|---|---|
| Math | Claude 3.5 Sonnet1.6 | Margin→ 24.8 | GPT-5.126.4 |
| Coding | Claude 3.5 Sonnet49.0 | MarginNo overlap | GPT-5.1Not measured |
| Knowledge | Claude 3.5 Sonnet59.4 | MarginNo overlap | GPT-5.1Not measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
FrontierMath v2 (Tiers 1-3)
MathA 2.069%B 31.034%Winner: GPT-5.1Δ 29FrontierMath v2 (Tiers 1-3): Claude 3.5 Sonnet scored 2.069%; GPT-5.1 scored 31.034%. GPT-5.1 wins this benchmark. - Source ↗
FrontierMath v2 (Tier 4)
MathA 0.000%B 12.500%Winner: GPT-5.1Δ 12.5FrontierMath v2 (Tier 4): Claude 3.5 Sonnet scored 0.000%; GPT-5.1 scored 12.500%. GPT-5.1 wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude 3.5 Sonnet | GPT-5.1 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude 3.5 Sonnet$3 input / $15 output | GPT-5.1$1.25 input / $10 output | GPT-5.1 has the lower combined listed price. |
| Generation speedtokens per second | Claude 3.5 SonnetNot available | GPT-5.1111 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude 3.5 SonnetNot available | GPT-5.157.47 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude 3.5 Sonnet200K | GPT-5.1200K | Listed context windows are equal. |
Benchmark Deep Dive
Agentic5 benchmarks
Coding4 benchmarks
Reasoning2 benchmarks
Knowledge7 benchmarks
| Benchmark | Claude 3.5 Sonnet | GPT-5.1 | Result |
|---|---|---|---|
| GPQASource | 59.4% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 36.9% | Not comparable |
| AA-GPQA DiamondSource | — | 87.3% | Not comparable |
| AA-HLESource | — | 26.5% | Not comparable |
| AA-Omniscience IndexSource | — | 5.6% | Not comparable |
| AA-Omniscience AccuracySource | — | 37.6% | Not comparable |
| AA-Omniscience Hallucination RateSource | — | 51.3% | Not comparable |
MathGPT-5.1 wins2 benchmarks
Multimodal2 benchmarks
Inst. Following1 benchmarks
| Benchmark | Claude 3.5 Sonnet | GPT-5.1 | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 72.9% | Not comparable |
Frequently Asked Questions (2)
Which is better, Claude 3.5 Sonnet or GPT-5.1?
GPT-5.1 is ahead on BenchLM's BenchAlign leaderboard, 53.65 to 47.74. The biggest single separator in this matchup is FrontierMath v2 (Tiers 1-3), where the scores are 2.069% and 31.034%.
Which is better for math, Claude 3.5 Sonnet or GPT-5.1?
GPT-5.1 has the edge for math in this comparison, averaging 26.4 versus 1.6. Inside this category, FrontierMath v2 (Tiers 1-3) is the benchmark that creates the most daylight between them.
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