Model comparison
Claude Haiku 4.5 vs GPT-5.1
Head-to-head evidence from 3 shared benchmark results across 2 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Haiku 4.5 #77 (Estimated); GPT-5.1 #94 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Haiku 4.5 and GPT-5.1 share 3 comparable benchmark results. 1 of 8 categories are comparable. 2 results are unique to Claude Haiku 4.5; 18 to GPT-5.1.
Updated July 20, 2026- Shared results
- 3
- Claude Haiku 4.5 only
- 2
- GPT-5.1 only
- 18
- Comparable categories
- 1 / 8
Pick Claude Haiku 4.5 if you want the stronger benchmark profile. GPT-5.1 only becomes the better choice if mathematics is the priority or you want the stronger reasoning-first profile.
Confidence note. This is a partial-evidence comparison with 3 shared benchmark results across 2 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
Claude Haiku 4.5 has the cleaner BenchAlign overall profile here, landing at 56.58 versus 53.65. It is a real lead, but still close enough that category-level strengths matter more than the headline number.
GPT-5.1 is also the more expensive model on tokens at $1.25 input / $10.00 output per 1M tokens, versus $1.00 input / $5.00 output per 1M tokens for Claude Haiku 4.5. That is roughly 2.0x on output cost alone. GPT-5.1 is the reasoning model in the pair, while Claude Haiku 4.5 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 Haiku 4.5 | Δ | GPT-5.1 |
|---|---|---|---|
| Math | Claude Haiku 4.54.9 | Margin→ 21.5 | GPT-5.126.4 |
| Coding | Claude Haiku 4.573.3 | 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 5.903%B 31.034%Winner: GPT-5.1Δ 25.1FrontierMath v2 (Tiers 1-3): Claude Haiku 4.5 scored 5.903%; GPT-5.1 scored 31.034%. GPT-5.1 wins this benchmark. - Source ↗
FrontierMath v2 (Tier 4)
MathA 2.083%B 12.500%Winner: GPT-5.1Δ 10.4FrontierMath v2 (Tier 4): Claude Haiku 4.5 scored 2.083%; 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 Haiku 4.5 | GPT-5.1 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Haiku 4.5$1 input / $5 output | GPT-5.1$1.25 input / $10 output | Claude Haiku 4.5 has the lower combined listed price. |
| Generation speedtokens per second | Claude Haiku 4.5Not available | GPT-5.1111 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Haiku 4.5Not available | GPT-5.157.47 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Haiku 4.5200K | GPT-5.1200K | Listed context windows are equal. |
Benchmark Deep Dive
Agentic6 benchmarks
Coding4 benchmarks
Reasoning2 benchmarks
Knowledge6 benchmarks
| Benchmark | Claude Haiku 4.5 | GPT-5.1 | Result |
|---|---|---|---|
| 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 Haiku 4.5 | GPT-5.1 | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 72.9% | Not comparable |
Frequently Asked Questions (2)
Which is better, Claude Haiku 4.5 or GPT-5.1?
Claude Haiku 4.5 is ahead on BenchLM's BenchAlign leaderboard, 56.58 to 53.65. The biggest single separator in this matchup is FrontierMath v2 (Tiers 1-3), where the scores are 5.903% and 31.034%.
Which is better for math, Claude Haiku 4.5 or GPT-5.1?
GPT-5.1 has the edge for math in this comparison, averaging 26.4 versus 4.9. Inside this category, FrontierMath v2 (Tiers 1-3) is the benchmark that creates the most daylight between them.
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