Model comparison
Claude 3.5 Sonnet vs Gemini 2.5 Flash
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 3.5 Sonnet #132 (Estimated); Gemini 2.5 Flash #130 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude 3.5 Sonnet and Gemini 2.5 Flash share 2 comparable benchmark results. 1 of 8 categories are comparable. 2 results are unique to Claude 3.5 Sonnet; 13 to Gemini 2.5 Flash.
Updated July 20, 2026- Shared results
- 2
- Claude 3.5 Sonnet only
- 2
- Gemini 2.5 Flash only
- 13
- Comparable categories
- 1 / 8
Pick Gemini 2.5 Flash if you want the stronger benchmark profile. Claude 3.5 Sonnet only becomes the better choice if its workflow or ecosystem matters more than the raw scoreboard.
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
Gemini 2.5 Flash has the cleaner BenchAlign overall profile here, landing at 48.09 versus 47.74. It is a real lead, but still close enough that category-level strengths matter more than the headline number.
Gemini 2.5 Flash's sharpest advantage is in mathematics, where it averages 4.7 against 1.6. The single biggest benchmark swing on the page is FrontierMath v2 (Tier 4), 0.000% to 4.167%.
Claude 3.5 Sonnet is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $0.30 input / $2.50 output per 1M tokens for Gemini 2.5 Flash. That is roughly 6.0x on output cost alone. Gemini 2.5 Flash gives you the larger context window at 1M, compared with 200K for Claude 3.5 Sonnet.
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 3.5 Sonnet | Δ | Gemini 2.5 Flash |
|---|---|---|---|
| Math | Claude 3.5 Sonnet1.6 | Margin→ 3.1 | Gemini 2.5 Flash4.7 |
| Coding | Claude 3.5 Sonnet49.0 | MarginNo overlap | Gemini 2.5 FlashNot measured |
| Knowledge | Claude 3.5 Sonnet59.4 | MarginNo overlap | Gemini 2.5 FlashNot measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
FrontierMath v2 (Tier 4)
MathA 0.000%B 4.167%Winner: Gemini 2.5 FlashΔ 4.2FrontierMath v2 (Tier 4): Claude 3.5 Sonnet scored 0.000%; Gemini 2.5 Flash scored 4.167%. Gemini 2.5 Flash wins this benchmark. - Source ↗
FrontierMath v2 (Tiers 1-3)
MathA 2.069%B 4.844%Winner: Gemini 2.5 FlashΔ 2.8FrontierMath v2 (Tiers 1-3): Claude 3.5 Sonnet scored 2.069%; Gemini 2.5 Flash scored 4.844%. Gemini 2.5 Flash wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude 3.5 Sonnet | Gemini 2.5 Flash | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude 3.5 Sonnet$3 input / $15 output | Gemini 2.5 Flash$0.3 input / $2.5 output | Gemini 2.5 Flash has the lower combined listed price. |
| Generation speedtokens per second | Claude 3.5 SonnetNot available | Gemini 2.5 Flash221 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude 3.5 SonnetNot available | Gemini 2.5 Flash0.50 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude 3.5 Sonnet200K | Gemini 2.5 Flash1M | Gemini 2.5 Flash lists the larger context window. |
Benchmark Deep Dive
Agentic1 benchmarks
| Benchmark | Claude 3.5 Sonnet | Gemini 2.5 Flash | Result |
|---|---|---|---|
| τ²-bench resultsSource | — | 14.9% | Not comparable |
Coding2 benchmarks
Reasoning2 benchmarks
Knowledge7 benchmarks
| Benchmark | Claude 3.5 Sonnet | Gemini 2.5 Flash | Result |
|---|---|---|---|
| GPQASource | 59.4% | — | Not comparable |
| 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 |
MathGemini 2.5 Flash wins2 benchmarks
Multimodal2 benchmarks
Inst. Following1 benchmarks
| Benchmark | Claude 3.5 Sonnet | Gemini 2.5 Flash | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 39.0% | Not comparable |
Frequently Asked Questions (2)
Which is better, Claude 3.5 Sonnet or Gemini 2.5 Flash?
Gemini 2.5 Flash is ahead on BenchLM's BenchAlign leaderboard, 48.09 to 47.74. The biggest single separator in this matchup is FrontierMath v2 (Tier 4), where the scores are 0.000% and 4.167%.
Which is better for math, Claude 3.5 Sonnet or Gemini 2.5 Flash?
Gemini 2.5 Flash has the edge for math in this comparison, averaging 4.7 versus 1.6. Inside this category, FrontierMath v2 (Tier 4) is the benchmark that creates the most daylight between them.
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