Pairwise benchmark snapshot · Aug 16, 2026
In this head-to-head showdown, Claude Sonnet 4.5 delivers higher overall intelligence and human-preferred responses (Elo 1,524 vs 1,466), while Claude Sonnet 4.5 leads in SWE-bench software engineering benchmarks (70.1%), while GPT-5.6 Luna is more budget-friendly at $1.2/1M per 1M output tokens. Review the complete breakdown below to determine which model best fits your performance and budget requirements.
10 direct benchmark disciplines evaluated across capability, speed, and cost
Workhorse Anthropic model: most of Opus coding quality at a mid-tier price.
OpenAI 5.6 fast/cheap tier. Official API $0.20/$1.20 per 1M after the Jul 30 80% Luna cut.
Currently comparing Claude Sonnet 4.5 vs GPT-5.6 Luna. Alternative family tiers available.
Δ 58 Arena Elo pts
188 tok/s
$1.2 / 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 Sonnet 4.5 | GPT-5.6 Luna | Advantage Delta |
|---|---|---|---|
| Preference Elo | +58 | ||
| Coding Elo | +73 | ||
| LiveBench | +3.2% | ||
| SWE-bench | +8.3% | ||
| GPQA Diamond | +4.8% | ||
| Time to first token | +152 ms | ||
| Output speed | 88 tok/s | 188 tok/s | +100 tok/s |
| Input price | +$2.8/1M | ||
| Output price | +$13.8/1M | ||
| Context window | +800k |
Simulate monthly production API costs in USD (US Dollar).
GPT-5.6 Luna is estimated to save $305.00/month ($3,660/year).
Higher SWE-bench (70.1%).
Lower output list price ($1.2/1M).
Lower TTFT (88 ms).
Larger window (1M).
Both accept images. Defaulting to the higher-Elo side (Claude Sonnet 4.5).
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | Claude Sonnet 4.5 | Higher SWE-bench (70.1%). |
| High-volume chat | GPT-5.6 Luna | Lower output list price ($1.2/1M). |
| Voice / low-latency UI | GPT-5.6 Luna | Lower TTFT (88 ms). |
| Long-document RAG | GPT-5.6 Luna | Larger window (1M). |
| Screenshots / vision | Claude Sonnet 4.5 | Both accept images. Defaulting to the higher-Elo side (Claude Sonnet 4.5). |
Luna is the OpenAI fast/cheap 5.6 SKU after Jul 30. It is not Sol. Sort by price and TTFT, not Elo.
Most of Opus 4.5 coding at a mid-tier price. Sonnet 5 replaced it as the buy; 4.5 remains a compare baseline.
High-volume agents that cannot pay Sol. Compare to Luna before you assume the new cheap SKU wins.
No comments posted on this matchup yet. Be the first to share an evaluation note!
Dynamic OpenGraph banner generated at /compare/claude-sonnet-4-5-vs-gpt-5-6-luna/opengraph-image
Verified Head-to-Head Telemetry
