Claude Sonnet 4.5 vs GPT-5.6 Luna
Side-by-side specs, pricing and capabilities. Both models run on Clade under one subscription, so you can switch between them in the same conversation.
Claude Sonnet 4.5 comes from Anthropic and GPT-5.6 Luna from OpenAI. The practical difference for most people is context, price, and which input types each one accepts.
GPT-5.6 Luna holds more in a single conversation — 1.1M tokens against 1M — which matters for long documents and large codebases.
GPT-5.6 Luna is the cheaper of the two on input tokens at $0.20 / 1M tokens.
| Specification | Claude Sonnet 4.5 | GPT-5.6 Luna |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Model ID | claude-sonnet-4-5-20250929 | gpt-5.6-luna |
| Context window | 1M | 1.1M |
| Max output | 64K | 128K |
| Input price | $3.00 / 1M tokens | $0.20 / 1M tokens |
| Output price | $15.00 / 1M tokens | $0.02 / 1M tokens |
| Knowledge cutoff | 2025-01 | — |
| Input types | text, image, file | text, image, file, audio |
| Output types | text | text |
| Plan | Premium | Free |
Which should you use?
Pick Claude Sonnet 4.5 when…
- You prefer Anthropic's tone and formatting for your work.
Pick GPT-5.6 Luna when…
- You need the larger context window — 1.1M against 1M.
- Cost matters: input runs at $0.20 / 1M tokens versus $3.00 / 1M tokens.
- You want longer single responses — up to 128K output tokens.
- You need audio input, which the other model does not accept.
- You are on the free plan — this model is included without an upgrade.
Related comparisons
Try both on Clade
You do not have to choose. One Clade subscription gives you Claude Sonnet 4.5, GPT-5.6 Luna, and every other model on the platform.