Model comparison
Gemini 3 Flash vs GPT-5.5 Pro
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: Gemini 3 Flash #49 (Supported); GPT-5.5 Pro #38 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Gemini 3 Flash and GPT-5.5 Pro share 3 comparable benchmark results. 1 of 8 categories are comparable. 16 results are unique to Gemini 3 Flash; 4 to GPT-5.5 Pro.
Updated July 22, 2026- Shared results
- 3
- Gemini 3 Flash only
- 16
- GPT-5.5 Pro only
- 4
- Comparable categories
- 1 / 8
Pick GPT-5.5 Pro if you want the stronger benchmark profile. Gemini 3 Flash 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 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
GPT-5.5 Pro is clearly ahead on the BenchAlign aggregate, 63.69 to 60.49. 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 27.8. The single biggest benchmark swing on the page is FrontierMath v2 (Tier 4), 4.167% to 39.600%.
GPT-5.5 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $0.50 input / $3.00 output per 1M tokens for Gemini 3 Flash. That is roughly 60.0x on output cost alone. GPT-5.5 Pro is the reasoning model in the pair, while Gemini 3 Flash 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 | Gemini 3 Flash | Δ | GPT-5.5 Pro |
|---|---|---|---|
| Math | Gemini 3 Flash27.8 | Margin→ 20.3 | GPT-5.5 Pro48.1 |
| Agentic | Gemini 3 FlashNot measured | MarginNo overlap | GPT-5.5 Pro90.1 |
| Knowledge | Gemini 3 FlashNot 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 (Tier 4)
MathA 4.167%B 39.600%Winner: GPT-5.5 ProΔ 35.4FrontierMath v2 (Tier 4): Gemini 3 Flash scored 4.167%; GPT-5.5 Pro scored 39.600%. GPT-5.5 Pro wins this benchmark. - Source ↗
FrontierMath v2 (Tiers 1-3)
MathA 35.640%B 51.000%Winner: GPT-5.5 ProΔ 15.4FrontierMath v2 (Tiers 1-3): Gemini 3 Flash scored 35.640%; GPT-5.5 Pro scored 51.000%. 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 | Gemini 3 Flash | GPT-5.5 Pro | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Gemini 3 Flash$0.5 input / $3 output | GPT-5.5 Pro$30 input / $180 output | Gemini 3 Flash has the lower combined listed price. |
| Generation speedtokens per second | Gemini 3 Flash159 tok/s | GPT-5.5 ProNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Gemini 3 Flash1.19 s | GPT-5.5 ProNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Gemini 3 Flash1M | GPT-5.5 Pro1M | Listed context windows are equal. |
Benchmark Deep Dive
Agentic5 benchmarks
Coding2 benchmarks
Reasoning2 benchmarks
Knowledge8 benchmarks
| Benchmark | Gemini 3 Flash | GPT-5.5 Pro | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 27.4% | — | Not comparable |
| AA-GPQA DiamondSource | 81.2% | — | Not comparable |
| AA-HLESource | 14.1% | — | Not comparable |
| AA-Omniscience IndexSource | -3.6% | — | Not comparable |
| AA-Omniscience AccuracySource | 45.5% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 90.2% | — | Not comparable |
| HLESource | — | 57.2% | Not comparable |
| HLE w/o toolsSource | — | 43.1% | Not comparable |
MathGPT-5.5 Pro wins3 benchmarks
Multimodal2 benchmarks
Inst. Following1 benchmarks
| Benchmark | Gemini 3 Flash | GPT-5.5 Pro | Result |
|---|---|---|---|
| AA-IFBenchSource | 55.1% | — | Not comparable |
Frequently Asked Questions (2)
Which is better, Gemini 3 Flash or GPT-5.5 Pro?
GPT-5.5 Pro is ahead on BenchLM's BenchAlign leaderboard, 63.69 to 60.49. The biggest single separator in this matchup is FrontierMath v2 (Tier 4), where the scores are 4.167% and 39.600%.
Which is better for math, Gemini 3 Flash or GPT-5.5 Pro?
GPT-5.5 Pro has the edge for math in this comparison, averaging 48.1 versus 27.8. Inside this category, FrontierMath v2 (Tier 4) is the benchmark that creates the most daylight between them.
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