Model comparison
GPT-5.5 Pro vs o3-mini
Head-to-head evidence from 0 shared benchmark results across 0 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.5 Pro #38 (Estimated); o3-mini #136 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.5 Pro and o3-mini share 0 comparable benchmark results. 1 of 8 categories are comparable. 7 results are unique to GPT-5.5 Pro; 10 to o3-mini.
Updated July 22, 2026- Shared results
- 0
- GPT-5.5 Pro only
- 7
- o3-mini only
- 10
- Comparable categories
- 1 / 8
Pick GPT-5.5 Pro if you want the stronger benchmark profile. o3-mini only becomes the better choice if knowledge is the priority or you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 0 shared benchmark results across 0 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
GPT-5.5 Pro is clearly ahead on the BenchAlign aggregate, 63.69 to 47.41. 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 $1.10 input / $4.40 output per 1M tokens for o3-mini. That is roughly 40.9x on output cost alone. GPT-5.5 Pro gives you the larger context window at 1M, compared with 200K for o3-mini.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.5 Pro | o3-mini | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.5 Pro$30 input / $180 output | o3-mini$1.1 input / $4.4 output | o3-mini has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.5 ProNot available | o3-mini160 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.5 ProNot available | o3-mini7.12 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.5 Pro1M | o3-mini200K | GPT-5.5 Pro lists the larger context window. |
Benchmark Deep Dive
Agentic2 benchmarks
Coding2 benchmarks
Reasoning1 benchmarks
| Benchmark | GPT-5.5 Pro | o3-mini | Result |
|---|---|---|---|
| CritPtSource | 30.6% | — | Not comparable |
Knowledgeo3-mini wins7 benchmarks
| Benchmark | GPT-5.5 Pro | o3-mini | Result |
|---|---|---|---|
| HLESource | 57.2% | — | Not comparable |
| HLE w/o toolsSource | 43.1% | — | Not comparable |
| MMLUSource | — | 86.9% | Not comparable |
| GPQASource | — | 77.2% | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 19.0% | Not comparable |
| AA-GPQA DiamondSource | — | 74.8% | Not comparable |
| AA-HLESource | — | 8.7% | Not comparable |
Math4 benchmarks
Inst. Following1 benchmarks
| Benchmark | GPT-5.5 Pro | o3-mini | Result |
|---|---|---|---|
| IFEvalSource | — | 93.9% | Not comparable |
Frequently Asked Questions (2)
Which is better, GPT-5.5 Pro or o3-mini?
GPT-5.5 Pro is ahead on BenchLM's BenchAlign leaderboard, 63.69 to 47.41.
Which is better for knowledge tasks, GPT-5.5 Pro or o3-mini?
o3-mini has the edge for knowledge tasks in this comparison, averaging 77.2 versus 57.2. GPT-5.5 Pro stays close enough that the answer can still flip depending on your workload.
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