Pairwise benchmark snapshot · Aug 17, 2026
In this head-to-head showdown, GPT-5.6 Luna delivers higher overall intelligence and human-preferred responses (Elo 1,466 vs 1,280), while GPT-5.6 Luna leads in SWE-bench software engineering benchmarks (61.8%), while GPT-5.6 Luna is more budget-friendly at $0.6/1M per 1M output tokens. Review the complete breakdown below to determine which model best fits your performance and budget requirements.
2024 workhorse. Still a high-intent compare against GPT-4o.
OpenAI 5.6 fast/cheap tier. Official API $0.20/$1.20 per 1M after the Jul 30 80% Luna cut.
Δ 186 Arena Elo pts
188 tok/s
$0.6 / 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 3.5 Sonnet | GPT-5.6 Luna | Advantage Delta |
|---|---|---|---|
| Preference Elo | GPT-5.6 Luna (+186) | ||
| Coding Elo | — | — | |
| LiveBench | GPT-5.6 Luna (+12.1%) | ||
| SWE-bench | GPT-5.6 Luna (+12.8%) | ||
| GPQA Diamond | GPT-5.6 Luna (+10.4%) | ||
| Time to first token | GPT-5.6 Luna (+192 ms) | ||
| Output speed | 80 tok/s | 188 tok/s | GPT-5.6 Luna (+108 tok/s) |
| Input price | $0.1/1M | GPT-5.6 Luna (+$2.9/1M) | |
| Output price | $0.6/1M | GPT-5.6 Luna (+$14.4/1M) | |
| Context window | GPT-5.6 Luna (+850k) |
Simulate monthly production API costs in USD (US Dollar).
GPT-5.6 Luna is estimated to save $317.50/month ($3,810/year).
Higher SWE-bench (61.8%).
Lower output list price ($0.6/1M).
Lower TTFT (88 ms).
Larger window (1.1M).
Both accept images. Defaulting to the higher-Elo side (GPT-5.6 Luna).
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | GPT-5.6 Luna | Higher SWE-bench (61.8%). |
| High-volume chat | GPT-5.6 Luna | Lower output list price ($0.6/1M). |
| Voice / low-latency UI | GPT-5.6 Luna | Lower TTFT (88 ms). |
| Long-document RAG | GPT-5.6 Luna | Larger window (1.1M). |
| Screenshots / vision | GPT-5.6 Luna | Both accept images. Defaulting to the higher-Elo side (GPT-5.6 Luna). |
Luna is the OpenAI fast/cheap 5.6 SKU after Jul 30. It is not Sol. Sort by price and TTFT, not Elo.
High-volume agents that cannot pay Sol. Compare to Luna before you assume the new cheap SKU wins.
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The real PNG is generated at /compare/claude-3-5-sonnet-vs-gpt-5-6-luna/opengraph-image for crawlers.
Verified head-to-head card
