Claude Opus 4.8 vs Grok 4.3
How Claude Opus 4.8 (Anthropic) and Grok 4.3 (xAI) compare on price and capabilities — and how to use either on anyAInow without a subscription.
Claude Opus 4.8
Flagship
Grok 4.3
Flagship
Provider
Anthropic
xAI
Best for
Flagship
Flagship
Reads images
Yes
Yes
GPQA Diamond
92%
90.1%
AA Coding Index
74.3%
42.2%
Price
from $30 / 1M
from $10 / 1M
Subscription
None
None
Benchmark source: artificialanalysis.ai, as of 13 Aug 2026. Higher is better; figures are publisher-reported where not independently verified.
Claude Opus 4.8 or Grok 4.3?
Claude Opus 4.8 and Grok 4.3 both sit in the flagship tier, so they're closely matched for everyday work. Grok 4.3 is the more cost-efficient of the two. On the GPQA Diamond reasoning benchmark, Claude Opus 4.8 leads 92% to 90.1%. On anyAInow you can use either — or run both side by side to see which answers your prompts better — pay-as-you-go with no subscription.