Claude Mythos 5 vs GPT-5.5 Pro
Detailed pricing comparison and cost analysis.
Updated September 2026
Cost Simulator
| Feature | Claude Mythos 5 | GPT-5.5 Pro |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Input Price (1M) | $10.00 | $30.00 |
| Output Price (1M) | $50.00 | $180.00 |
| Context Window | 1,000,000 | 1,000,000 |
Verdict
Claude Mythos 5 costs $10.00 per 1M input tokens and $50.00 per 1M output tokens. GPT-5.5 Pro costs $30.00 per 1M input tokens and $180.00 per 1M output tokens. Claude Mythos 5 is 67% cheaper on input tokens than GPT-5.5 Pro. For output tokens, Claude Mythos 5 is the more affordable option at $50.00/1M vs $180.00.
On context window, Claude Mythos 5 supports 1,000,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose Claude Mythos 5
- ✓ You need the lowest input token cost ($ 10.00/1M)
- ✓ Your workload is output-heavy — Claude Mythos 5 generates text cheaper
- ✓ You are already integrated with Anthropic
When to choose GPT-5.5 Pro
- ✓ You are already integrated with OpenAI
Use the calculator above to simulate your specific workload and find the exact break-even point. For most applications, the cheapest model is the one that minimises your total monthly bill given your input-to-output token ratio.
Frequently Asked Questions
Is Claude Mythos 5 cheaper than GPT-5.5 Pro? ▼
Claude Mythos 5 is cheaper on input tokens at $10.00/1M vs $30.00/1M for GPT-5.5 Pro — a 67% saving.
What is the context window of Claude Mythos 5 vs GPT-5.5 Pro? ▼
Claude Mythos 5 has a 1,000,000-token context window. GPT-5.5 Pro has a 1,000,000-token context window. Claude Mythos 5 supports the larger context, suitable for longer documents and agentic workflows.
Which model is better: Claude Mythos 5 or GPT-5.5 Pro? ▼
The best choice depends on your use case. For cost efficiency on input tokens, Claude Mythos 5 is the cheaper option. For maximum context length, Claude Mythos 5 supports 1,000,000 tokens. Use the comparison table above to find the right fit for your workload.