High-volume, cost-sensitive work
Either one
Both cost $4.00 per million tokens on a typical mix of three input tokens for every output token.
Claude Sonnet 5.5 vs Kimi K3.1 Pro: price, context and capabilities
Choose Claude Sonnet 5.5 for reused prompts and documents (RAG, agents). Choose Kimi K3.1 Pro for the latest release.
In short
- Both cost the same at the headline price ($4.00 / 1M tokens).
- Kimi K3.1 Pro reads more per request: 1.05M tokens against 1M.
- Kimi K3.1 Pro is the newer model (Oct 23, 2026, against September 2026).
- Only Claude Sonnet 5.5 offers batch api.
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Reused prompts and documents (RAG, agents)
Choose Claude Sonnet 5.5
Claude Sonnet 5.5 charges $0.10 per million cached input tokens, against $0.20 for Kimi K3.1 Pro.
Latest release
Choose Kimi K3.1 Pro
Kimi K3.1 Pro is the newer release (Oct 23, 2026, against September 2026 for Claude Sonnet 5.5).
Monthly cost at three volumes
| Volume | Claude Sonnet 5.5 | Kimi K3.1 Pro | Difference |
|---|---|---|---|
| Prototype: 1M input, 250K output tokens | $4.50 | $4.50 | = |
| Production: 20M input, 5M output tokens | $90.00 | $90.00 | = |
| Scale: 500M input, 100M output tokens | $2,000 | $2,000 | = |
Standard rates, without caching or batch discounts. Volumes are per month.
Specifications side by side
| Claude Sonnet 5.5 | Kimi K3.1 Pro | |
|---|---|---|
| Provider | Anthropic | Moonshot AI |
| Category | Language models | Language models |
| Status | Generally available | Generally available |
| Headline price | $4.00 / 1M tokens | $4.00 / 1M tokens |
| Input | $2.00 / 1M tokens | $2.00 / 1M tokens |
| Output | $10.00 / 1M tokens | $10.00 / 1M tokens |
| Cached input | $0.10 / 1M tokens | $0.20 / 1M tokens |
| Context window | 1M | 1.05M |
| Max output | 128k | 944k |
| Released | September 2026 | Oct 23, 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 |
| API model id | claude-sonnet-5-5 | kimi-k3.1-pro |
Benchmarks side by side
Leader in bold.
| Benchmark | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Intelligence Index | 56 | No data |
| SciCode | 61% | No data |
| Humanity's Last Exam | 55% | No data |
| Long-context reasoning (AA-LCR) | 82.7% | No data |
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 Kimi K3.1 Pro?
Choose Claude Sonnet 5.5 for reused prompts and documents (RAG, agents). Choose Kimi K3.1 Pro for the latest release.
Which is cheaper, Claude Sonnet 5.5 or Kimi K3.1 Pro?
Both cost the same at the headline price ($4.00 / 1M tokens).
Which has the larger context window, Claude Sonnet 5.5 or Kimi K3.1 Pro?
Kimi K3.1 Pro reads more per request: 1.05M tokens against 1M.
What is the difference between Claude Sonnet 5.5 and Kimi K3.1 Pro?
Claude Sonnet 5.5 is made by Anthropic and Kimi K3.1 Pro by Moonshot AI. Both cost the same at the headline price ($4.00 / 1M tokens). Kimi K3.1 Pro reads more per request: 1.05M tokens against 1M. Kimi K3.1 Pro is the newer model (Oct 23, 2026, against September 2026). Only Claude Sonnet 5.5 offers batch api.
How much do Claude Sonnet 5.5 and Kimi K3.1 Pro cost per month?
At 20 million input and 5 million output tokens a month, Claude Sonnet 5.5 costs $90.00 and Kimi K3.1 Pro costs $90.00, at standard rates.
Which is newer, Claude Sonnet 5.5 or Kimi K3.1 Pro?
Kimi K3.1 Pro was released on Oct 23, 2026 and Claude Sonnet 5.5 on September 2026.