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Claude Mythos 5.1 vs DeepSeek V4-Flash

Detailed pricing comparison and cost analysis.

Updated September 2026

Cost Simulator

Claude Mythos 5.1 Cost
$20.00
DeepSeek V4-Flash Cost
$0.70
DeepSeek V4-Flash is 96% cheaper
FeatureClaude Mythos 5.1DeepSeek V4-Flash
ProviderAnthropicDeepSeek
Input Price (1M)$10.00$0.44
Output Price (1M)$50.00$1.32
Context Window1,000,0001,000,000

Verdict

Claude Mythos 5.1 costs $10.00 per 1M input tokens and $50.00 per 1M output tokens. DeepSeek V4-Flash costs $0.44 per 1M input tokens and $1.32 per 1M output tokens. DeepSeek V4-Flash is 96% cheaper on input tokens than Claude Mythos 5.1. For output tokens, DeepSeek V4-Flash is the more affordable option at $1.32/1M 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 are already integrated with Anthropic

When to choose DeepSeek V4-Flash

  • ✓ You need the lowest input token cost ($ 0.44/1M)
  • ✓ Your workload is output-heavy — DeepSeek V4-Flash generates text cheaper
  • ✓ You are already integrated with DeepSeek

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 DeepSeek V4-Flash?

DeepSeek V4-Flash is cheaper on input tokens at $0.44/1M vs $10.00/1M for Claude Mythos 5.1 — a 96% saving.

What is the context window of Claude Mythos 5.1 vs DeepSeek V4-Flash?

Claude Mythos 5.1 has a 1,000,000-token context window. DeepSeek V4-Flash has a 1,000,000-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 DeepSeek V4-Flash?

The best choice depends on your use case. For cost efficiency on input tokens, DeepSeek V4-Flash 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.