Model comparison
Gemini 2.5 Flash vs o4-mini (high)
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: Gemini 2.5 Flash #130 (Supported); o4-mini (high) #118 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Gemini 2.5 Flash and o4-mini (high) share 2 comparable benchmark results. 1 of 8 categories are comparable. 13 results are unique to Gemini 2.5 Flash; 0 to o4-mini (high).
Updated July 20, 2026- Shared results
- 2
- Gemini 2.5 Flash only
- 13
- o4-mini (high) only
- 0
- Comparable categories
- 1 / 8
Pick o4-mini (high) if you want the stronger benchmark profile. Gemini 2.5 Flash only becomes the better choice if you need the larger 1M context window 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
o4-mini (high) has the cleaner BenchAlign overall profile here, landing at 49.98 versus 48.09. It is a real lead, but still close enough that category-level strengths matter more than the headline number.
o4-mini (high)'s sharpest advantage is in mathematics, where it averages 20.2 against 4.7. The single biggest benchmark swing on the page is FrontierMath v2 (Tiers 1-3), 4.844% to 24.828%.
o4-mini (high) is the reasoning model in the pair, while Gemini 2.5 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. Gemini 2.5 Flash gives you the larger context window at 1M, compared with 200K for o4-mini (high).
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 2.5 Flash | Δ | o4-mini (high) |
|---|---|---|---|
| Math | Gemini 2.5 Flash4.7 | Margin→ 15.5 | o4-mini (high)20.2 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
FrontierMath v2 (Tiers 1-3)
MathA 4.844%B 24.828%Winner: o4-mini (high)Δ 20FrontierMath v2 (Tiers 1-3): Gemini 2.5 Flash scored 4.844%; o4-mini (high) scored 24.828%. o4-mini (high) wins this benchmark. - Source ↗
FrontierMath v2 (Tier 4)
MathA 4.167%B 6.250%Winner: o4-mini (high)Δ 2.1FrontierMath v2 (Tier 4): Gemini 2.5 Flash scored 4.167%; o4-mini (high) scored 6.250%. o4-mini (high) wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Gemini 2.5 Flash | o4-mini (high) | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Gemini 2.5 Flash$0.3 input / $2.5 output | o4-mini (high)Not available | A complete price comparison is not available. |
| Generation speedtokens per second | Gemini 2.5 Flash221 tok/s | o4-mini (high)161 tok/s | Gemini 2.5 Flash has the higher measured throughput. |
| First-answer latencyseconds to first token | Gemini 2.5 Flash0.50 s | o4-mini (high)21.94 s | Gemini 2.5 Flash reaches the first token sooner. |
| Context windowmaximum listed tokens | Gemini 2.5 Flash1M | o4-mini (high)200K | Gemini 2.5 Flash lists the larger context window. |
Benchmark Deep Dive
Agentic1 benchmarks
| Benchmark | Gemini 2.5 Flash | o4-mini (high) | Result |
|---|---|---|---|
| τ²-bench resultsSource | 14.9% | — | Not comparable |
Coding1 benchmarks
| Benchmark | Gemini 2.5 Flash | o4-mini (high) | Result |
|---|---|---|---|
| AA-SciCodeSource | 29.1% | — | Not comparable |
Reasoning2 benchmarks
Knowledge6 benchmarks
| Benchmark | Gemini 2.5 Flash | o4-mini (high) | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 14.1% | — | Not comparable |
| AA-GPQA DiamondSource | 68.3% | — | Not comparable |
| AA-HLESource | 5.1% | — | Not comparable |
| AA-Omniscience IndexSource | -42.0% | — | Not comparable |
| AA-Omniscience AccuracySource | 26.5% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 93.3% | — | Not comparable |
Matho4-mini (high) wins2 benchmarks
Multimodal2 benchmarks
Inst. Following1 benchmarks
| Benchmark | Gemini 2.5 Flash | o4-mini (high) | Result |
|---|---|---|---|
| AA-IFBenchSource | 39.0% | — | Not comparable |
Frequently Asked Questions (2)
Which is better, Gemini 2.5 Flash or o4-mini (high)?
o4-mini (high) is ahead on BenchLM's BenchAlign leaderboard, 49.98 to 48.09. The biggest single separator in this matchup is FrontierMath v2 (Tiers 1-3), where the scores are 4.844% and 24.828%.
Which is better for math, Gemini 2.5 Flash or o4-mini (high)?
o4-mini (high) has the edge for math in this comparison, averaging 20.2 versus 4.7. Inside this category, FrontierMath v2 (Tiers 1-3) is the benchmark that creates the most daylight between them.
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