Grok 4.5 vs Claude Opus 4.8
xAI put Grok 4.5 straight up against Claude Opus 4.8 on July 8, 2026, and the pitch is price. Grok 4.5, built on the 1.5 trillion parameter V9 foundation and trained on real coding-agent data, lands fourth on the Artificial Analysis Intelligence Index at $2 input / $6 output per 1M tokens, more than 60% below Opus 4.8 at $5 / $25. Grok leads Opus on the provider-harness DeepSWE 1.0 score and on Terminal-Bench 2.1 (83.3), but Opus 4.8 pulls ahead on the neutral DeepSWE 1.1 run and on SWE-Bench Pro (64.7 for Grok), and it ships a 1M context window against Grok's 500K. The choice comes down to cheap coding throughput versus verified accuracy and longer context.
Head-to-Head Specs
| Spec | Grok 4.5 | Claude Opus 4.8 |
|---|---|---|
| Provider | xAI | Anthropic |
| Input Price | $2.00/1M | $5.00/1M |
| Output Price | $6.00/1M | $25.00/1M |
| Context Window | 500K | 1M |
| Released | 2026-07 | 2026-05 |
| Capabilities | text, vision, tool-use, code, reasoning | text, vision, tool-use, code |
Category Breakdown
Grok 4.5 is $2/$6 per 1M tokens vs Opus 4.8 at $5/$25, roughly 60 to 76% cheaper
Grok 4.5 leads on the provider harness at 83.3 and on DeepSWE 1.0
Opus 4.8 edges Grok 4.5, which scores 64.7 on the neutral SWE-Bench Pro run
Opus 4.8 leads on the neutral DeepSWE 1.1 harness where provider tuning is removed
Opus 4.8 ships 1M tokens vs Grok 4.5 at 500K
Grok 4.5 integrates native X and web search tools for live-grounded agents
Choose Grok 4.5 when:
- ▸Cost-sensitive coding and agentic pipelines
- ▸Terminal and shell-style agent tasks
- ▸Real-time X and web-grounded agents
- ▸Frontier-class index score at budget pricing
Choose Claude Opus 4.8 when:
- ▸Maximum verified coding accuracy
- ▸Workloads that need a 1M token context window
- ▸The hardest reasoning and knowledge work
- ▸Mature Anthropic ecosystem and MCP tooling
Frequently Asked Questions
Which is better, Grok 4.5 or Claude Opus 4.8?
It depends on your use case. Grok 4.5 from xAI excels at cost-sensitive coding and agentic pipelines, while Claude Opus 4.8 from Anthropic is better for maximum verified coding accuracy. See the full comparison above for detailed benchmarks and pricing.
How much does Grok 4.5 cost compared to Claude Opus 4.8?
Grok 4.5 costs $2.00 input and $6.00 output per 1M tokens. Claude Opus 4.8 costs $5.00 input and $25.00 output per 1M tokens.
What is the context window difference between Grok 4.5 and Claude Opus 4.8?
Grok 4.5 supports 500K tokens, while Claude Opus 4.8 supports 1M tokens.