Pairwise benchmark snapshot · Aug 16, 2026
In this head-to-head showdown, Claude Opus 4.8 delivers higher overall intelligence and human-preferred responses (Elo 1,598 vs 1,295), while Claude Opus 4.8 leads in SWE-bench software engineering benchmarks (78.4%), while Gemini 2.5 Flash is more budget-friendly at $0.4/1M per 1M output tokens. Review the complete breakdown below to determine which model best fits your performance and budget requirements.
8 direct benchmark disciplines evaluated across capability, speed, and cost
Prior Opus generation still billed at $5/$25. Kept as a compare baseline against Opus 5.
Previous Google speed workhorse.
Currently comparing Claude Opus 4.8 vs Gemini 2.5 Flash. Alternative family tiers available.
Simulate accuracy gains vs added response time & token cost
Reasoning models “think before answering” by generating internal reasoning tokens. Higher effort improves math, coding, and logic accuracy, but increases response delay and token costs.
Δ 303 Arena Elo pts
185 tok/s
$0.4 / 1M output
Relative percentile scores computed across all active models in the benchmark catalog.
Comparing top Western standard models with China's leading frontier rival across 6 skill dimensions. Tap any spoke or dot to inspect.
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 Opus 4.8 | Gemini 2.5 Flash | Advantage Delta |
|---|---|---|---|
| Preference Elo | +303 | ||
| Coding Elo | — | — | |
| LiveBench | +22.2% | ||
| SWE-bench | +30.4% | ||
| GPQA Diamond | +18% | ||
| Time to first token | +220 ms | ||
| Output speed | 66 tok/s | 185 tok/s | +119 tok/s |
| Input price | $0.1/1M | +$4.9/1M | |
| Output price | $0.4/1M | +$24.6/1M | |
| Context window | — |
Simulate monthly production API costs in USD (US Dollar).
Gemini 2.5 Flash is estimated to save $540.50/month ($6,486/year).
Higher SWE-bench (78.4%).
Lower output list price ($0.4/1M).
Lower TTFT (110 ms).
Larger window (1M).
Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.8).
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | Claude Opus 4.8 | Higher SWE-bench (78.4%). |
| High-volume chat | Gemini 2.5 Flash | Lower output list price ($0.4/1M). |
| Voice / low-latency UI | Gemini 2.5 Flash | Lower TTFT (110 ms). |
| Long-document RAG | Claude Opus 4.8 | Larger window (1M). |
| Screenshots / vision | Claude Opus 4.8 | Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.8). |
Opus 4.8 still bills $5/$25. We keep it so Opus 5 vs 4.8 is a real generation delta, not marketing.
Useful as a cheap historical compare. 3.7 Flash is the 2026 volume SKU.
No comments posted on this matchup yet. Be the first to share an evaluation note!
Dynamic OpenGraph banner generated at /compare/claude-opus-4-8-vs-gemini-2-5-flash/opengraph-image
Verified Head-to-Head Telemetry