Pairwise benchmark snapshot · Aug 17, 2026
In this head-to-head showdown, Claude Sonnet 4 delivers higher overall intelligence and human-preferred responses (Elo 1,455 vs 1,295), while Claude Sonnet 4 leads in SWE-bench software engineering benchmarks (62.8%), while Gemini 2.5 Flash is more budget-friendly at $2.5/1M per 1M output tokens. Review the complete breakdown below to determine which model best fits your performance and budget requirements.
First Sonnet 4 generation. Bridge between 3.5/3.7 and Sonnet 5.
Δ 160 Arena Elo pts
185 tok/s
$2.5 / 1M output
Relative percentile scores computed across all active models in the benchmark catalog.
Each spoke is a skill. Farther from the center is better (0–100th percentile). Tap any dot to inspect details.
Category wins across reasoning intelligence, generation speed, and token cost.
Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy
Generation throughput and time to first token responsiveness
Cost per million tokens and max context window length
| Benchmark | Claude Sonnet 4 | Gemini 2.5 Flash | Advantage Delta |
|---|---|---|---|
| Preference Elo | Claude Sonnet 4 (+160) | ||
| Coding Elo | — | — | |
| LiveBench | Claude Sonnet 4 (+11.8%) | ||
| SWE-bench | Claude Sonnet 4 (+14.8%) | ||
| GPQA Diamond | Claude Sonnet 4 (+8.2%) | ||
| Time to first token | Gemini 2.5 Flash (+110 ms) | ||
| Output speed | 92 tok/s | 185 tok/s | Gemini 2.5 Flash (+93 tok/s) |
| Input price | $0.3/1M | Gemini 2.5 Flash (+$2.7/1M) | |
| Output price | $2.5/1M | Gemini 2.5 Flash (+$12.5/1M) | |
| Context window | Gemini 2.5 Flash (+49k) |
Simulate monthly production API costs in USD (US Dollar).
Gemini 2.5 Flash is estimated to save $282.00/month ($3,384/year).
Higher SWE-bench (62.8%).
Lower output list price ($2.5/1M).
Lower TTFT (110 ms).
Larger window (1M).
Both accept images. Defaulting to the higher-Elo side (Claude Sonnet 4).
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | Claude Sonnet 4 | Higher SWE-bench (62.8%). |
| High-volume chat | Gemini 2.5 Flash | Lower output list price ($2.5/1M). |
| Voice / low-latency UI | Gemini 2.5 Flash | Lower TTFT (110 ms). |
| Long-document RAG | Gemini 2.5 Flash | Larger window (1M). |
| Screenshots / vision | Claude Sonnet 4 | Both accept images. Defaulting to the higher-Elo side (Claude Sonnet 4). |
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The real PNG is generated at /compare/claude-sonnet-4-vs-gemini-2-5-flash/opengraph-image for crawlers.
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