Model comparison
GPT-5.5 Pro vs Mistral Small 4 (Reasoning)
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); Mistral Small 4 (Reasoning) unranked (Not scored). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.5 Pro and Mistral Small 4 (Reasoning) share 1 comparable benchmark result. 0 of 8 categories are comparable. 6 results are unique to GPT-5.5 Pro; 15 to Mistral Small 4 (Reasoning).
Updated July 22, 2026- Shared results
- 1
- GPT-5.5 Pro only
- 6
- Mistral Small 4 (Reasoning) only
- 15
- Comparable categories
- 0 / 8
Benchmark data for GPT-5.5 Pro and Mistral Small 4 (Reasoning) is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 1 shared benchmark result across 1 evidence category; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
BenchLM has partial data for these models, but not enough overlapping benchmark coverage to produce a fair score-level comparison yet.
GPT-5.5 Pro is priced at $30.00 input / $180.00 output per 1M tokens, versus $0.15 input / $0.60 output per 1M tokens for Mistral Small 4 (Reasoning). GPT-5.5 Pro has the larger context window at 1M, compared with 256K for Mistral Small 4 (Reasoning).
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 | Mistral Small 4 (Reasoning) |
|---|---|---|---|
| Agentic | GPT-5.5 Pro90.1 | MarginNo overlap | Mistral Small 4 (Reasoning)Not measured |
| Knowledge | GPT-5.5 Pro57.2 | MarginNo overlap | Mistral Small 4 (Reasoning)Not measured |
| Math | GPT-5.5 Pro48.1 | MarginNo overlap | Mistral Small 4 (Reasoning)Not measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.5 Pro | Mistral Small 4 (Reasoning) | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.5 Pro$30 input / $180 output | Mistral Small 4 (Reasoning)$0.15 input / $0.6 output | Mistral Small 4 (Reasoning) has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.5 ProNot available | Mistral Small 4 (Reasoning)Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.5 ProNot available | Mistral Small 4 (Reasoning)Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.5 Pro1M | Mistral Small 4 (Reasoning)256K | GPT-5.5 Pro lists the larger context window. |
Benchmark Deep Dive
Agentic5 benchmarks
Coding2 benchmarks
Reasoning2 benchmarks
Knowledge8 benchmarks
| Benchmark | GPT-5.5 Pro | Mistral Small 4 (Reasoning) | Result |
|---|---|---|---|
| HLESource | 57.2% | — | Not comparable |
| HLE w/o toolsSource | 43.1% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 19.6% | Not comparable |
| AA-GPQA DiamondSource | — | 76.9% | Not comparable |
| AA-HLESource | — | 9.5% | Not comparable |
| AA-Omniscience IndexSource | — | -29.9% | Not comparable |
| AA-Omniscience AccuracySource | — | 22.1% | Not comparable |
| AA-Omniscience Hallucination RateSource | — | 66.8% | Not comparable |
Math3 benchmarks
Multimodal1 benchmarks
| Benchmark | GPT-5.5 Pro | Mistral Small 4 (Reasoning) | Result |
|---|---|---|---|
| AA-MMMU-ProSource | — | 56.8% | Not comparable |
Inst. Following1 benchmarks
| Benchmark | GPT-5.5 Pro | Mistral Small 4 (Reasoning) | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 48.2% | Not comparable |
Frequently Asked Questions (3)
Can I compare GPT-5.5 Pro and Mistral Small 4 (Reasoning) on BenchLM yet?
Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.
Why does this comparison show “coming soon”?
BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.
What data is available for GPT-5.5 Pro and Mistral Small 4 (Reasoning) today?
GPT-5.5 Pro: $30.00 input / $180.00 output per 1M tokens Mistral Small 4 (Reasoning): $0.15 input / $0.60 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
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