Claude Mythos Preview vs Claude Sonnet 5
Wins 3 of 4 areas
Coding · Reasoning · Images and charts
Wins 0 of 4 areas
—
Claude Mythos Preview is the stronger all-rounder.
Scores updated · 15 tests both models report · How we compare
Where each one wins
Tests won in each of the four areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- CodingWriting and fixing software30Claude Mythos Preview3 of 3 tests
- ReasoningHard problems that need careful thinking20Claude Mythos Preview2 of 2 tests
- Images and chartsUnderstanding pictures, charts and video10Claude Mythos Preview1 of 1 test
- AgentsCarrying out multi-step tasks on its own11Even1 each
Images and charts rests on a single test.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where Claude Mythos Preview pulls ahead
- Very hard expert questions across many subjectsHumanity's Last Exam+23.4points ahead
- Long, multi-file coding tasks in real codebasesSWE-bench Pro+14.6points ahead
- Fixes real GitHub issues in many programming languagesSWE-bench Multilingual+9points ahead
Where Claude Sonnet 5 pulls ahead
- Completes tasks by operating a computer desktopOSWorld-Verified+1.6points ahead
Every test, side by side
All 15 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Mythos Preview
- SWE-bench ProClaude Mythos Preview by 14.677.863.2+14.6
- SWE-bench MultilingualClaude Mythos Preview by 987.378.3+9
- SWE-bench VerifiedClaude Mythos Preview by 8.793.985.2+8.7
AgentsEven
- BrowseCompClaude Mythos Preview by 2.286.984.7+2.2
- OSWorld-VerifiedClaude Sonnet 5 by 1.679.681.2+1.6
ReasoningClaude Mythos Preview
- Humanity's Last ExamClaude Mythos Preview by 23.464.741.3+23.4
- GPQA DiamondClaude Mythos Preview by 3.594.691.1+3.5
Images and chartsClaude Mythos Preview
- CharXiv (RQ)Claude Mythos Preview by 4.993.288.3+4.9
Other results7 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- SWE-bench MultimodalClaude Mythos Preview by 30.95928.1+30.9
- HLE (with tools)Claude Mythos Preview by 7.364.757.4+7.3
- HealthBench ProfessionalClaude Mythos Preview by 6.964.757.8+6.9
- Legal Agent Benchmark, Full Public SetClaude Mythos Preview by 4.513.48.9+4.5
- CharXiv Reasoning (With tools)Claude Mythos Preview by 4.292.588.3+4.2
- HealthBenchClaude Mythos Preview by 1.961.159.2+1.9
- Terminal-Bench 2.0Claude Mythos Preview by 1.68280.4+1.6
Questions people ask
Which is better, Claude Mythos Preview or Claude Sonnet 5?
Claude Mythos Preview wins three of the four areas where both have results: coding, reasoning and images and charts. Claude Sonnet 5 wins none. They are level on agents.
Which is better for coding?
Claude Mythos Preview. It wins 3 of the 3 coding tests both models report; Claude Sonnet 5 wins none.
How do you compare the two?
We use the 15 benchmark tests both models have published scores on. The verdict counts the 8 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 7 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.