Model comparison
Claude Opus 4.8 vs Grok 4.20 Reasoning
Compare Claude Opus 4.8 vs Grok 4.20 Reasoning API pricing: input/output token costs, cache pricing, context windows, workload estimates, and routing fit.
Claude Opus 4.8
anthropic · claude-opus-4-8
- Input
- $5
- Output
- $25
- Context
- 1M
Grok 4.20 Reasoning
xai · grok-4.20-0309-reasoning
- Input
- $1.25
- Output
- $2.5
- Context
- 1M
Quick take
Grok 4.20 Reasoning has the lower input price at $1.25 per 1M input tokens. Grok 4.20 Reasoning is cheaper for the example blended workload below. Claude Opus 4.8 has the larger context window at 1M tokens.
Choose Claude Opus 4.8 if...
- Claude Opus 4.8 is required if images, screenshots, or visual documents are part of the workflow.
Choose Grok 4.20 Reasoning if...
- Grok 4.20 Reasoning is the better default for cost-sensitive traffic and repeated high-volume calls.
- Grok 4.20 Reasoning gives more room for long generated answers, reports, or code output.
Example workload cost
Estimates use input tokens plus 20% output tokens. They exclude provider discounts, cache hits, and tool/search surcharges.
| Workload | Claude Opus 4.8 | Grok 4.20 Reasoning | Cheaper |
|---|---|---|---|
| 1M input + 200K output | $10.00 | $1.75 | Grok 4.20 Reasoning |
| 10M input + 2M output | $100.00 | $17.50 | Grok 4.20 Reasoning |
| 100M input + 20M output | $1,000.00 | $175.00 | Grok 4.20 Reasoning |
Context, output, and capability fit
Claude Opus 4.8 provides the larger context window. Check max output separately when the task needs long reports, code generation, or full-document rewrites.
- Claude Opus 4.8 max output
- 128K
- Grok 4.20 Reasoning max output
- 1M
- Claude Opus 4.8 features
- prompt caching, function calling, vision
- Grok 4.20 Reasoning features
- prompt caching, function calling
Risk notes for Claude Opus 4.8
- High output price: cap max tokens for verbose generation workloads.
Risk notes for Grok 4.20 Reasoning
- No major capability risk is flagged in this snapshot, but provider pages should still be verified before production routing.
Routing tags
frontierpremiumreasoningcodingagentslong-contextmultimodalcache-friendlyrag