claude-sonnet-5.5-high vs grok-4.20-beta-0309-reasoning Benchmark Comparison

Direct benchmark comparison between claude-sonnet-5.5-high and grok-4.20-beta-0309-reasoning based on LMArena Elo and the latest 2026 API pricing.

Direct Technical & Pricing Comparison

Frontier Model	LMArena Elo	API Cost (1M)	Throughput
claude-sonnet-5.5-high	1699	$0.000002	102
grok-4.20-beta-0309-reasoning	1471	$0.00000125	64

*These models represent the Pareto Frontier (optimal cost-to-performance).*

Comparison Summary: claude-sonnet-5.5-high is the more capable model in this pair, leading by 227 Elo points.