Model comparison
Claude Haiku 4.5 vs GPT-5.5 Pro
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 Haiku 4.5 #77 (Estimated); GPT-5.5 Pro #38 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Haiku 4.5 and GPT-5.5 Pro share 2 comparable benchmark results. 1 of 8 categories are comparable. 3 results are unique to Claude Haiku 4.5; 5 to GPT-5.5 Pro.
Updated July 22, 2026- Shared results
- 2
- Claude Haiku 4.5 only
- 3
- GPT-5.5 Pro only
- 5
- Comparable categories
- 1 / 8
Pick GPT-5.5 Pro if you want the stronger benchmark profile. Claude Haiku 4.5 only becomes the better choice if you want the cheaper token bill or 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-5.5 Pro is clearly ahead on the BenchAlign aggregate, 63.69 to 56.58. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.5 Pro's sharpest advantage is in mathematics, where it averages 48.1 against 4.9. The single biggest benchmark swing on the page is FrontierMath v2 (Tiers 1-3), 5.903% to 51.000%.
GPT-5.5 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $1.00 input / $5.00 output per 1M tokens for Claude Haiku 4.5. That is roughly 36.0x on output cost alone. GPT-5.5 Pro 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. GPT-5.5 Pro gives you the larger context window at 1M, compared with 200K for Claude Haiku 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 | Claude Haiku 4.5 | Δ | GPT-5.5 Pro |
|---|---|---|---|
| Math | Claude Haiku 4.54.9 | Margin→ 43.2 | GPT-5.5 Pro48.1 |
| Agentic | Claude Haiku 4.5Not measured | MarginNo overlap | GPT-5.5 Pro90.1 |
| Coding | Claude Haiku 4.573.3 | MarginNo overlap | GPT-5.5 ProNot measured |
| Knowledge | Claude Haiku 4.5Not measured | MarginNo overlap | GPT-5.5 Pro57.2 |
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 51.000%Winner: GPT-5.5 ProΔ 45.1FrontierMath v2 (Tiers 1-3): Claude Haiku 4.5 scored 5.903%; GPT-5.5 Pro scored 51.000%. GPT-5.5 Pro wins this benchmark. - Source ↗
FrontierMath v2 (Tier 4)
MathA 2.083%B 39.600%Winner: GPT-5.5 ProΔ 37.5FrontierMath v2 (Tier 4): Claude Haiku 4.5 scored 2.083%; GPT-5.5 Pro scored 39.600%. GPT-5.5 Pro 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-5.5 Pro | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Haiku 4.5$1 input / $5 output | GPT-5.5 Pro$30 input / $180 output | Claude Haiku 4.5 has the lower combined listed price. |
| Generation speedtokens per second | Claude Haiku 4.5Not available | GPT-5.5 ProNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Haiku 4.5Not available | GPT-5.5 ProNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Haiku 4.5200K | GPT-5.5 Pro1M | GPT-5.5 Pro lists the larger context window. |
Benchmark Deep Dive
Agentic2 benchmarks
Coding1 benchmarks
| Benchmark | Claude Haiku 4.5 | GPT-5.5 Pro | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 73.3% | — | Not comparable |
Reasoning1 benchmarks
| Benchmark | Claude Haiku 4.5 | GPT-5.5 Pro | Result |
|---|---|---|---|
| CritPtSource | — | 30.6% | Not comparable |
Knowledge2 benchmarks
MathGPT-5.5 Pro wins3 benchmarks
Multimodal1 benchmarks
| Benchmark | Claude Haiku 4.5 | GPT-5.5 Pro | Result |
|---|---|---|---|
| Design Arena WebsiteSource | 1152 | — | Not comparable |
Frequently Asked Questions (2)
Which is better, Claude Haiku 4.5 or GPT-5.5 Pro?
GPT-5.5 Pro is ahead on BenchLM's BenchAlign leaderboard, 63.69 to 56.58. The biggest single separator in this matchup is FrontierMath v2 (Tiers 1-3), where the scores are 5.903% and 51.000%.
Which is better for math, Claude Haiku 4.5 or GPT-5.5 Pro?
GPT-5.5 Pro has the edge for math in this comparison, averaging 48.1 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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