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Claude Mythos 5.1 vs o4-mini

Detailed pricing comparison and cost analysis.

Updated September 2026

Cost Simulator

Claude Mythos 5.1 Cost
$20.00
o4-mini Cost
$1.98
o4-mini is 90% cheaper
FeatureClaude Mythos 5.1o4-mini
ProviderAnthropicOpenAI
Input Price (1M)$10.00$1.10
Output Price (1M)$50.00$4.40
Context Window1,000,000200,000

Verdict

Claude Mythos 5.1 costs $10.00 per 1M input tokens and $50.00 per 1M output tokens. o4-mini costs $1.10 per 1M input tokens and $4.40 per 1M output tokens. o4-mini is 89% cheaper on input tokens than Claude Mythos 5.1. For output tokens, o4-mini is the more affordable option at $4.40/1M vs $50.00.

On context window, Claude Mythos 5.1 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 5.1

  • ✓ You need a larger context window (1,000,000 tokens)
  • ✓ You are already integrated with Anthropic

When to choose o4-mini

  • ✓ You need the lowest input token cost ($ 1.10/1M)
  • ✓ Your workload is output-heavy — o4-mini generates text cheaper
  • ✓ 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 5.1 cheaper than o4-mini?

o4-mini is cheaper on input tokens at $1.10/1M vs $10.00/1M for Claude Mythos 5.1 — a 89% saving.

What is the context window of Claude Mythos 5.1 vs o4-mini?

Claude Mythos 5.1 has a 1,000,000-token context window. o4-mini has a 200,000-token context window. Claude Mythos 5.1 supports the larger context, suitable for longer documents and agentic workflows.

Which model is better: Claude Mythos 5.1 or o4-mini?

The best choice depends on your use case. For cost efficiency on input tokens, o4-mini is the cheaper option. For maximum context length, Claude Mythos 5.1 supports 1,000,000 tokens. Use the comparison table above to find the right fit for your workload.