Claude Opus 5.5 vs Kimi K3.1 Pro
A side-by-side comparison of Claude Opus 5.5 from Anthropic and Kimi K3.1 Pro from Moonshot AI, using published pricing, context windows, supported inputs, and release dates.
- Claude Opus 5.5 input
- $4
- Kimi K3.1 Pro input
- $2
Key differences
Kimi K3.1 Pro is 50% cheaper on input tokens ($2 vs $4 per 1M).
Kimi K3.1 Pro has the larger context window: 1.05M vs 1M tokens.
Kimi K3.1 Pro is the newer release (Oct 23, 2026, vs Sep 22, 2026).
Claude Opus 5.5 vs Kimi K3.1 Pro specs
| Spec | Claude Opus 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Provider | Anthropic | Moonshot AI |
| Released | Sep 22, 2026 | Oct 23, 2026 |
| Context window | 1,000,000 tokens | 1,048,576 tokens |
| Input price / 1M tokens | $4 | $2 |
| Output price / 1M tokens | $20 | $10 |
| 10K in + 1K out request | $0.06 | $0.03 |
| Accepts | file, image, text | image, text, video |
| Produces | text | text |
| Tool calling | Yes | Yes |
| Structured outputs | Yes | Yes |
| Reasoning | Yes | Yes |
| Popularity | 47/100 | 41/100 |
Highlighted values are better on that spec: lower price, larger context window, newer release, or higher popularity. Prices in USD per 1M tokens as listed on OpenRouter.
Claude Opus 5.5 vs Kimi K3.1 Pro questions
Is Claude Opus 5.5 or Kimi K3.1 Pro cheaper?
Kimi K3.1 Pro has the lower listed input price ($2 per million tokens). For a request with 10,000 input and 1,000 output tokens, Claude Opus 5.5 costs about $0.06 and Kimi K3.1 Pro about $0.03.
Which has the larger context window?
Kimi K3.1 Pro supports 1,048,576 tokens, the larger of the two.
Which model should I choose?
Pick the cheaper model for high-volume, simpler tasks, and test both on a sample of your real prompts before committing. Price and context size do not measure output quality on your specific workload.