Kimi K3 vs Claude Opus 5: same-tier frontier reasoning, very different price?
By TechCompare · Updated · How we check
Kimi K3 is the value-frontier pick for same-tier reasoning. Pick Opus 5 only when Anthropic's tooling, safety tuning, or instruction-following edge cases are the deciding factor, and budget the premium.
MoonshotAI: Kimi K3
Moonshot AI's own price
- Input
- $3
- Output
- $15
- Cached
- $0.30
per 1M tokens
Price checked 2026-11-12
Anthropic: Claude Opus 5
Anthropic's own price
- Input
- $5
- Output
- $25
- Cached
- $0.50
per 1M tokens
Price checked 2026-11-12
Cost Comparison
Based on 100,000 input tokens (50% cached), 5,000 output tokens, and 100 requests.Prices come live from OpenRouter at each maker's own price where it's listed. Temporary deals are left out.
Kimi K3 is Moonshot AI's frontier reasoning model and often lands in the same smartness tier as Claude Opus 5. The comparison tests whether a non-US frontier lab can deliver top-tier reasoning at meaningfully lower per-token cost, and on paper, it can.
A frontier-tier reasoner from Moonshot AI against Anthropic's Opus 5. Compare the cost of a finished task.
Side-by-side specs
| Spec | Kimi K3 | Claude Opus 5 |
|---|---|---|
| Input Cost (per M) | $3.00 (better on this spec) | $5.00 |
| Output Cost (per M) | $15.00 (better on this spec) | $25.00 |
| Cached Input (per M)Cached input is text the provider has already processed. It costs less than fresh input. | $0.30 (better on this spec) | $0.50 |
| Batch input / output (per M) | None | $2.50 / $12.50 |
| Context Window | 1M | 1M |
How they differ
Kimi K3 is priced at $3.00 per million input tokens and $15.00 per million output tokens, with a 90% caching discount ($0.30 per million) and a 1M context window. Claude Opus 5 is priced at $5.00 per million input tokens and $25.00 per million output tokens, also with a 90% caching discount ($0.50 per million) and a 1M context window.
For a typical 100K input + 10K output request, Kimi K3 costs $0.45 vs Opus 5's $0.75, so Kimi is cheaper per call. Both are text-in / text-out with file input. K3 lacks Anthropic's mature tool ecosystem and Claude's refined instruction-following nuance, but for pure reasoning at the frontier tier, the per-token economics favor Kimi.
Verdict
Reach for Opus 5 when its tool ecosystem and safety tuning earn the premium in ops cost. Kimi K3 charges $3.00/M input and $15.00/M output against Opus 5's $5.00 and $25.00, about 40% and 40% cheaper on the base rows. Cached input mirrors that at $0.30/M versus $0.50/M. Opus's batch prices drop output to $12.50/M, under Kimi's $15/M live price on async bulk work. Context ties at 1M.
Which should you pick?
Choose Kimi K3
High-volume frontier reasoning where per-token cost dominates. Kimi K3's discount of about 40% on input and 40% on output makes it the economical choice at scale.
Choose Claude Opus 5
Tasks that lean on Anthropic's specific instruction-following nuance, mature tool-calling API, or safety-policy tuning. The premium earns its keep when those features directly reduce ops cost.