tokevenClaudevsClaude
Claude Opus 4.8 vs Claude Mythos 5.1
Side-by-side comparison of pricing, task quality, and projected cost at higher scale.
Pricing
Side-by-side pricing
Claude Opus 4.8
FlagshipClaude Mythos 5.1
FlagshipInput $/MTok
$5.00
$10.00
Output $/MTok
$25.00
$50.00
Cache discount
90% off
98% off
Context
1,000K
1,000K
Quality
Task confidence comparison
Confidence score from zero to one hundred by task type, where higher is better.
Code Generation
95
vs
0
Code Review
94
vs
0
Summarization
88
vs
0
Q&A
85
vs
0
Extraction
82
vs
0
Reasoning
97
vs
0
Classification
80
vs
0
Creative Writing
93
vs
0
Claude Opus 4.8
Claude Mythos 5.1
Guidance
When to use Claude Opus 4.8 vs Claude Mythos 5.1
Choose Claude Opus 4.8 when...
- -Cost matters: 50% cheaper on input tokens
Choose Claude Mythos 5.1 when...
- Similar performance; consider provider preference or ecosystem fit.
At scale
Cost at scale
Estimated cost assuming a seventy percent input and thirty percent output token split.
Claude Opus 4.8
Claude Mythos 5.1
100K tokens
$1.10Cheaper
$2.20
1M tokens
$11.00Cheaper
$22.00
10M tokens
$110.00Cheaper
$220.00
FAQ
When should I use Claude Opus 4.8 instead of Claude Mythos 5.1?
Claude Opus 4.8 and Claude Mythos 5.1 perform similarly across all tracked tasks. Pick based on pricing and provider preference.
Is Claude Mythos 5.1 cheaper than Claude Opus 4.8?
Claude Mythos 5.1 input costs $10.00/MTok, which is 100% more than Claude Opus 4.8 at $5.00/MTok.
What are the context window sizes for Claude Opus 4.8 and Claude Mythos 5.1?
Claude Opus 4.8 has a 1,000K token context window. Claude Mythos 5.1 has a 1,000K token context window.
Go deeper on either model
Per-call cost calculators, provider lineups, and price history for both models on this page.
Other comparisons
How Claude Opus 4.8 and Claude Mythos 5.1 stack up against the rest of the field.
Track your real costs
Comparisons show estimated costs at list price. The dashboard reveals your real spend and savings.