Claude Mythos 5 vs Grok 4.5
Side-by-side comparison of API pricing, specs, benchmarks, and capabilities
| Specification |
by Anthropic
|
by xAI
|
|---|---|---|
| Overview | ||
| Status | Current flagship | Current flagship |
| Released | Jun 9, 2026 | Jul 8, 2026 |
| Pricing per million tokens | ||
| Input | $10.00/Mtok | $2.00/Mtok |
| Output | $50.00/Mtok | $6.00/Mtok |
| Blended avg | $20.00/Mtok | $3.00/Mtok |
| Cached input | $1.00/Mtok | — |
| Specifications | ||
| Context window | 1M tokens | 500K tokens |
| Parameters | Proprietary | Proprietary |
| Speed (TPS) | — | — |
| Modalities | ||
| Input |
textimage
|
textimage
|
| Benchmarks sources: Vellum LLM Leaderboard / Artificial Analysis, LMSYS Chatbot Arena (UC Berkeley), xAI Grok 4.5 launch post | ||
| Terminal-Bench 2.1 | 88 | 83.3 vendor |
| Avg benchmark score | 87.5 | — |
| Perf / dollar | 4.4 | — |
| GPQA Diamond | 94.1 | — |
| SWE-Bench Verified | 95.5 | — |
| Humanity's Last Exam | 64.5 | — |
| HumanEval | 95.5 | — |
| Independent composite scores each on its own scale — not part of the average above | ||
| AA Intelligence Index | — | 55.8 |
| AA Agentic Index | — | 48.9 |
| AA-Omniscience Index (−100–100) | — | 25.3 |
| GDPval-AA v2 | — | 1526.4 ELO |
| LMSYS Chatbot Arena | — | 1469.6 ELO |
| Providers | ||
| Available from |
Anthropic — $10.00/$50.00/Mtok
|
xAI — $2.00/$6.00/Mtok
|
Cost at scale
1M tokens · 50/50 input/output| Volume | Claude Mythos 5 | Grok 4.5 | Savings |
|---|---|---|---|
| 1M tokens | $20 | $3 | $17 (85%) |
| 10M tokens | $200 | $30 | $170 (85%) |
| 100M tokens | $2000 | $300 | $1700 (85%) |
| 1000M tokens | $20000 | $3000 | $17000 (85%) |
When to pick which
distilled from the pricing and spec data above- your workload re-reads context (agents, RAG, long chats): cached input costs $1.00/Mtok — 90% off its list input price, a discount Grok 4.5 doesn't offer
- you need the longer context: 1M tokens vs 500K (2×)
- cost dominates: $3.00/Mtok blended vs $20.00 — 85% less on the same 50/50 token mix
The cheaper option here — Grok 4.5 costs $3.00/Mtok blended on xAI.
Summary
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.
Grok 4.5 by xAI costs $2.00/Mtok input and $6.00/Mtok output, with a 500K-token context window. It supports text, image input.
On a blended cost basis, Grok 4.5 is 85% cheaper than Claude Mythos 5.
The two aren't directly comparable on average benchmark score: Claude Mythos 5 has published per-benchmark results, while Grok 4.5 does not yet — it is measured today on independent composites (see the table above).
Note: Pricing is per million tokens. Actual costs vary with usage patterns, prompt caching, and batch discounts. Always verify against official provider pricing pages.