High-volume, cost-sensitive work
Choose Grok 4.5
Grok 4.5 costs 25% less on a typical mix of three input tokens for every output token ($3.00 against $4.00 per million tokens).
Claude Sonnet 5.5 vs Grok 4.5: price, context and capabilities
Choose Claude Sonnet 5.5 for reused prompts and documents (RAG, agents), very long inputs, the hardest reasoning tasks, reasoning over long documents and the latest release. Choose Grok 4.5 for high-volume, cost-sensitive work and writing and code generation.
In short
- Grok 4.5 is 25% cheaper than Claude Sonnet 5.5 at the headline price ($3.00 / 1M tokens vs $4.00 / 1M tokens).
- Claude Sonnet 5.5 reads more per request: 1M tokens against 500k.
- Claude Sonnet 5.5 is the newer model (September 2026, against July 2026).
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Writing and code generation
Choose Grok 4.5
Grok 4.5 charges $6.00 per million output tokens, against $10.00 for Claude Sonnet 5.5. Output dominates the bill when answers are long.
Reused prompts and documents (RAG, agents)
Choose Claude Sonnet 5.5
Claude Sonnet 5.5 charges $0.10 per million cached input tokens, against $0.30 for Grok 4.5.
Very long inputs
Choose Claude Sonnet 5.5
Claude Sonnet 5.5 reads up to 1M tokens per request, against 500k for Grok 4.5.
Hardest reasoning tasks
Choose Claude Sonnet 5.5
Claude Sonnet 5.5 scores 56 on the Artificial Analysis Intelligence Index, against 38.8 for Grok 4.5.
Reasoning over long documents
Choose Claude Sonnet 5.5
Claude Sonnet 5.5 scores 82.7% on Long-context reasoning (AA-LCR), against 79.3% for Grok 4.5.
Latest release
Choose Claude Sonnet 5.5
Claude Sonnet 5.5 is the newer release (September 2026, against July 2026 for Grok 4.5).
Monthly cost at three volumes
| Volume | Claude Sonnet 5.5 | Grok 4.5 | Difference |
|---|---|---|---|
| Prototype: 1M input, 250K output tokens | $4.50 | $3.50 | Grok 4.5, $1.00 less |
| Production: 20M input, 5M output tokens | $90.00 | $70.00 | Grok 4.5, $20.00 less |
| Scale: 500M input, 100M output tokens | $2,000 | $1,600 | Grok 4.5, $400.00 less |
Standard rates, without caching or batch discounts. Volumes are per month.
Specifications side by side
| Claude Sonnet 5.5 | Grok 4.5 | |
|---|---|---|
| Provider | Anthropic | xAI |
| Category | Language models | Language models |
| Status | Generally available | Legacy |
| Headline price | $4.00 / 1M tokens | $3.00 / 1M tokens |
| Input | $2.00 / 1M tokens | $2.00 / 1M tokens |
| Output | $10.00 / 1M tokens | $6.00 / 1M tokens |
| Cached input | $0.10 / 1M tokens | $0.30 / 1M tokens |
| Context window | 1M | 500k |
| Max output | 128k | No data |
| Released | September 2026 | July 2026 |
| Knowledge cutoff | June 2026 | No data |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API |
| API model id | claude-sonnet-5-5 | grok-4.5 |
Benchmarks side by side
Leader in bold.
| Benchmark | Claude Sonnet 5.5 | Grok 4.5 |
|---|---|---|
| Intelligence Index | 56 | 38.8 |
| SciCode | 61% | 55% |
| Humanity's Last Exam | 55% | 42.7% |
| Long-context reasoning (AA-LCR) | 82.7% | 79.3% |
| GPQA Diamond | No data | 93.1% |
| MMMU-Pro (visual reasoning) | No data | 80.4% |
Independent evaluations by Artificial Analysis, run the same way for every model, at the reasoning setting shown. Percentages unless marked as an index.
Frequently asked questions
Should I choose Claude Sonnet 5.5 or Grok 4.5?
Choose Claude Sonnet 5.5 for reused prompts and documents (RAG, agents), very long inputs, the hardest reasoning tasks, reasoning over long documents and the latest release. Choose Grok 4.5 for high-volume, cost-sensitive work and writing and code generation.
Which is cheaper, Claude Sonnet 5.5 or Grok 4.5?
Grok 4.5 is 25% cheaper than Claude Sonnet 5.5 at the headline price ($3.00 / 1M tokens vs $4.00 / 1M tokens).
Which has the larger context window, Claude Sonnet 5.5 or Grok 4.5?
Claude Sonnet 5.5 reads more per request: 1M tokens against 500k.
What is the difference between Claude Sonnet 5.5 and Grok 4.5?
Claude Sonnet 5.5 is made by Anthropic and Grok 4.5 by xAI. Grok 4.5 is 25% cheaper than Claude Sonnet 5.5 at the headline price ($3.00 / 1M tokens vs $4.00 / 1M tokens). Claude Sonnet 5.5 reads more per request: 1M tokens against 500k. Claude Sonnet 5.5 is the newer model (September 2026, against July 2026).
How much do Claude Sonnet 5.5 and Grok 4.5 cost per month?
At 20 million input and 5 million output tokens a month, Claude Sonnet 5.5 costs $90.00 and Grok 4.5 costs $70.00, at standard rates.
Which is newer, Claude Sonnet 5.5 or Grok 4.5?
Claude Sonnet 5.5 was released on September 2026 and Grok 4.5 on July 2026.