GPT-6 Luna Pro vs Claude Opus 5.5: price, context window and capabilities
GPT-6 Luna Pro (openai/gpt-6-luna-pro) from OpenAI and Claude Opus 5.5 (anthropic/claude-opus-5.5) from Anthropic are both multimodal language models on the OceanToken API. GPT-6 Luna Pro costs less per token than Claude Opus 5.5: $0.10 against $3.60 per 1M input tokens (97% less) and $0.50 against $18.00 per 1M output tokens (97% less). Claude Opus 5.5 is 10% off its official price on OceanToken, for every account. GPT-6 Luna Pro has the larger context window: 1.05M tokens (1,050,000) against 1M (1,000,000) for Claude Opus 5.5. Both support tool calling, reasoning, structured outputs, image input and file input.
Side by side
| Spec | GPT-6 Luna Pro | Claude Opus 5.5 −10% |
|---|---|---|
| Model | GPT-6 Luna Proopenai/ | Claude Opus 5.5anthropic/ |
| Publisher | OpenAI | Anthropic |
| Kind | Text & vision | Text & vision |
| Context window | 1.05M tokens1,050,000 | 1M tokens1,000,000 |
| Input price | $0.10 / 1M tokens | $3.60 / 1M tokens |
| Output price | $0.50 / 1M tokens | $18.00 / 1M tokens |
| Cached input price | $0.01 / 1M tokens | $0.20 / 1M tokens |
| Cache write price | $0.125 / 1M tokens | $5.00 / 1M tokens |
| Web search price | $0.01 / search | $0.01 / search |
| Discount (vs official, top tier) | — | −10% |
| Inputs | text, images and files | text, images and files |
| Outputs | text | text |
| Tool calling | Yes | Yes |
| Reasoning | Yes | Yes |
| Structured outputs | Yes | Yes |
About these prices
Which should you choose?
- Choose GPT-6 Luna Pro to spend less per token: 97% less for input and 97% less for output than Claude Opus 5.5.
- Choose GPT-6 Luna Pro for the longest inputs: its context window holds 1.05M tokens against 1M for Claude Opus 5.5.
- Both list the same capabilities: tool calling, reasoning, structured outputs, image input and file input.
- Not sure? Call both with the same OceanToken API key and compare them on your own prompts; each request is billed per use from one prepaid balance.
Get API Key GPT-6 Luna Pro Claude Opus 5.5
Frequently asked questions
Which is cheaper, GPT-6 Luna Pro or Claude Opus 5.5?
GPT-6 Luna Pro. GPT-6 Luna Pro costs less per token than Claude Opus 5.5: $0.10 against $3.60 per 1M input tokens (97% less) and $0.50 against $18.00 per 1M output tokens (97% less). Claude Opus 5.5 is 10% off its official price on OceanToken, for every account. The OceanToken console always shows the current price.
Which has the larger context window, GPT-6 Luna Pro or Claude Opus 5.5?
GPT-6 Luna Pro. GPT-6 Luna Pro has the larger context window: 1.05M tokens (1,050,000) against 1M (1,000,000) for Claude Opus 5.5.
Can I call both GPT-6 Luna Pro and Claude Opus 5.5 with one API key?
Yes. Both are on the OceanToken API at https://api.oceantoken.ai/v1: one API key and one prepaid balance call either model. Send the model id openai/gpt-6-luna-pro or anthropic/claude-opus-5.5.
Models and publishers
GPT-6 Luna Pro · Claude Opus 5.5 · All OpenAI models · All Anthropic models
More comparisons
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