Claude Mythos 5.1 vs Claude Mythos 5
Side-by-side comparison of API pricing, specs, benchmarks, and capabilities
| Specification |
by Anthropic
|
by Anthropic
|
|---|---|---|
| Overview | ||
| Status | Current flagship | Current flagship |
| Released | Sep 1, 2026 | Jun 9, 2026 |
| Pricing per million tokens | ||
| Input | $10.00/Mtok | $10.00/Mtok |
| Output | $50.00/Mtok | $50.00/Mtok |
| Blended avg | $20.00/Mtok | $20.00/Mtok |
| Cached input | $0.250/Mtok | $1.00/Mtok |
| Price basis | Cache hits and refreshes on Claude Mythos 5.1 (and Claude Fable 5.1) are priced at 0.025x the base input price — $0.25 per 1M tokens — where every other Claude model uses the standard 0.1x multiplier. Base $10/$50 per 1M tokens; Batch API $5/$25. Verified 2026-09-01 against platform.claude.com/docs/en/about-claude/pricing. | — |
| Specifications | ||
| Context window | 1M tokens | 1M tokens |
| Parameters | Proprietary | Proprietary |
| Speed (TPS) | — | — |
| Modalities | ||
| Input |
textimage
|
textimage
|
| Benchmarks source: Vellum LLM Leaderboard | ||
| Avg benchmark score | 55.9 | 87.5 |
| Perf / dollar | 2.8 | 4.4 |
| Terminal-Bench 2.1 | 60.9 | 88 |
| Humanity's Last Exam | 65 | 64.5 |
| GPQA Diamond | — | 94.1 |
| SWE-Bench Verified | — | 95.5 |
| OSWorld-Verified | 41.7 | — |
| HumanEval | — | 95.5 |
| AutoBench | 31.4 | — |
| Providers | ||
| Available from |
Anthropic — $10.00/$50.00/Mtok
|
Anthropic — $10.00/$50.00/Mtok
|
Cost at scale
1M tokens · 50/50 input/output| Volume | Claude Mythos 5.1 | Claude Mythos 5 | Savings |
|---|---|---|---|
| 1M tokens | $20 | $20 | $0 (0%) |
| 10M tokens | $200 | $200 | $0 (0%) |
| 100M tokens | $2000 | $2000 | $0 (0%) |
| 1000M tokens | $20000 | $20000 | $0 (0%) |
When to pick which
distilled from the pricing and spec data above- your workload re-reads context (agents, RAG, long chats): cached input costs $0.250/Mtok — 98% off its list input price
- raw capability matters more than price: 87.5 vs 55.9 average benchmark score
The cheaper option here — Claude Mythos 5.1 costs $20.00/Mtok blended on Anthropic.
Summary
Claude Mythos 5.1 by Anthropic costs $10.00/Mtok input and $50.00/Mtok output, with a 1M-token context window. It supports text, image input.
Claude Mythos 5 by Anthropic costs $10.00/Mtok input and $50.00/Mtok output, with a 1M-token context window. It supports text, image input.
On benchmarks, Claude Mythos 5 scores higher (87.5 vs 55.9) on average. In terms of value, Claude Mythos 5 has better performance per dollar (4.4 vs 2.8).
Note: Pricing is per million tokens. Actual costs vary with usage patterns, prompt caching, and batch discounts. Always verify against official provider pricing pages.