Kimi K3 vs Claude Opus 5.5
Kimi K3 costs $3.00 / $15.00 and Claude Opus 5.5 costs $4.00 / $20.00 per million input / output tokens. At a typical 3:1 mix, Kimi K3 is 1.3× cheaper than Claude Opus 5.5.
Input
$3.00
per 1M
Output
$15.00
per 1M
Cached
$0.30
1M context
Claude Opus 5.5
Anthropic
Input
$4.00
per 1M
Output
$20.00
per 1M
Cached
$0.20
1M context
Side by side
Green marks the cheaper price, larger context window, bigger discount or higher score.
| Detail | Kimi K3 | Claude Opus 5.5 |
|---|---|---|
| Input per 1M | $3.00 | $4.00 |
| Output per 1M | $15.00 | $20.00 |
| Blended per 1M (3:1) | $6.00 | $8.00 |
| Cached input per 1M | $0.30 | $0.20 |
| Batch or off-peak discount | None | 50% (batch) |
| Long prompts | Same rate at any length | Same rate at any length |
| Context window | 1M | 1M |
| Released | 16 Jul 2026 | 22 Sep 2026 |
| Open weights | Yes | No |
| Arena text score | 1488 | 1509 |
| Verified | 27 Sep 2026 | 27 Sep 2026 |
Sources: Kimi API pricing and Anthropic pricing.
Monthly cost on three workloads
List prices, no batch discount. The cached share applies where a model has a cache rate.
| Workload | Kimi K3 | Claude Opus 5.5 | Difference |
|---|---|---|---|
| Customer chat assistant50,000 conversations a month, about 2,000 tokens in and 400 out each; 50% cached | $465 | $610 | $145 |
| Document Q&A (RAG)20,000 questions a month over retrieved documents, 12,000 in and 600 out; 30% cached | $706 | $926 | $221 |
| Coding agent400 tasks a month, 40 steps each with a growing context; 85% cached | $649 | $738 | $88.75 |
How they differ
- Kimi K3 is cheaper on input ($3 vs $4).
- Kimi K3 is cheaper on output ($15 vs $20), which matters most for long answers and reasoning models.
- Kimi K3 accepts longer prompts (1M vs 1M tokens).
- Cached input is cheaper on Claude Opus 5.5 ($0.20 vs $0.30), which favours agents and chat apps that resend the same context.
- Only Claude Opus 5.5 offers a batch discount for jobs that can wait.
- Kimi K3 has open weights, so you can also run it yourself or choose between hosts.
- On the Arena text leaderboard (25 Sep 2026), Claude Opus 5.5 scores higher (1509 vs 1488). Test both on your own prompts before deciding.
Recent changes
All changes- ▼ 20%Claude Opus 5.5 launched at $4 / $20 per 1M tokens, 20% below Opus 5.
- Anthropic retired Claude Opus 4.1.
- Anthropic launched Claude Opus 5 at $5 / $25.
- Moonshot launched Kimi K3 at $3 / $15.
- Anthropic retired Claude Opus 4 and Claude Sonnet 4.
