# Kimi K3 vs Claude Fable 5 and Opus 5.5: price, context and access By SeedRouter · Published 2026-09-28 · Updated 2026-09-28 Kimi K3 is the cheapest of the three per token and the only one with open weights. At list prices it costs 25% less than Claude Opus 5.5 and 70% less than Claude Fable 5 for both input and output. All three read 1M tokens of context and reason before they answer. Kimi K3 can write a much longer answer in one request, while the Claude models accept images by URL and give you more effort levels. Which one does better on your work is something to test: each vendor publishes its own benchmarks, and none of them measured your prompts. ## How do Kimi K3 and Claude compare at a glance? | | Kimi K3 | Claude Opus 5.5 | Claude Fable 5 | | ----------------------------------------- | ---------------------------------- | --------------------------- | --------------------------- | | Maker | Moonshot AI | Anthropic | Anthropic | | Weights | Open | Closed | Closed | | Context window | 1M tokens | 1M tokens | 1M tokens | | Max output | 1,048,576 tokens (default 131,072) | 128K tokens | 128K tokens | | Reasoning | Always on | Adaptive, always on | Adaptive, always on | | Effort levels | `low`, `high`, `max` | `low` to `max`, five levels | `low` to `max`, five levels | | Default effort | `max` | `medium` | `high` | | Image input | Base64 only | Base64 or URL | Base64 or URL | | List price per token, relative to Kimi K3 | 1× | 1.33× | 3.33× | The ratios apply to input and output alike, and come from the list prices published by [Moonshot](https://platform.kimi.ai/docs/pricing/chat) and [Anthropic](https://platform.claude.com/docs/en/about-claude/pricing). Claude Fable 5.1 has the same list price as Claude Fable 5. ## Is Kimi K3 cheaper than Claude? Yes, on input and output. At list price, Claude Opus 5.5 costs a third more per token than Kimi K3, and Claude Fable 5 costs 3.3 times as much. Output costs five times input on all three, so the gap holds whatever your mix of reading and writing. Two things shift the real bill. All three bill reasoning as output, so a model that thinks longer on your task costs more even at the same rate. And all three discount cached input: Kimi K3 charges a tenth of its input rate for a cache hit, and the Claude models discount cache hits too, at rates that differ by model. The current SeedRouter rates: ### Kimi K3 Current rates are temporarily unavailable. No price estimate is provided; unavailable rates must not be interpreted as free usage. ### Claude Fable 5 Current rates are temporarily unavailable. No price estimate is provided; unavailable rates must not be interpreted as free usage. ### Claude Opus 5.5 Current rates are temporarily unavailable. No price estimate is provided; unavailable rates must not be interpreted as free usage. ## Which one handles longer work? On context, it is a tie: each reads up to 1M tokens. On output, Kimi K3 goes much further. It writes up to 1,048,576 tokens in one request, reasoning included, against 128K for the Claude models. That matters for very long generations, such as whole files or large refactors in one pass. For most answers, 128K is more than enough. ## How do reasoning controls differ? All three reason before they answer, and you cannot switch it off. Kimi K3 has three effort levels and starts at `max`, the most thorough and the most output-hungry setting. Claude Opus 5.5 starts at `medium` and Claude Fable 5 at `high`, each with five levels from `low` to `max`. In practice, set the effort yourself on all three. On Kimi K3, `high` or `low` avoids paying for `max` reasoning on routine steps. ## Is Kimi K3 better than Claude Fable 5? There is no single answer, and the published numbers do not settle it. Moonshot's [Kimi K3 technical blog](https://www.kimi.com/blog/kimi-k3) and Anthropic's model pages each report benchmarks chosen and run by the vendor. Treat them as a shortlist, not a verdict. The practical test is short: send the same five or ten prompts from your own work to each model, at the effort you would use in production, and compare answers and token counts. The [Kimi K3 playground](https://seedrouter.ai/models/kimi-k3#playground) and the [Claude Fable 5 playground](https://seedrouter.ai/models/claude-fable-5#playground) show the cost of every answer, so you see quality and price side by side. ## Can I switch between them without rewriting code? Yes, on SeedRouter. One key calls all of them, and each takes the same three request formats: Chat Completions, Responses and Anthropic Messages. Changing `model` from `claude-opus-5-5` to `kimi-k3` is the whole switch. Two differences to handle: * **Images.** Kimi K3 takes images only as base64 data URIs. If your Claude code sends image URLs, encode the images first. * **Sampling.** Kimi K3 fixes `temperature` at 1.0 and `top_p` at 0.95 and rejects other values, so remove them from the request. ## Which should I pick? * **Pick Kimi K3** when price per token matters, when you want open weights you could self-host later, or when one request has to write a very long output. * **Pick Claude Opus 5.5** when you want Anthropic's model at the lower of the two Claude prices, or need images by URL. * **Pick Claude Fable 5** when your own tests show it does the job better and the higher price is worth it for that task. ## Frequently asked questions ### Is Kimi K3 as good as Claude Opus 5.5? Moonshot and Anthropic each publish benchmarks for their own models. Run your own prompts on both before switching a production workload. ### Can I use Kimi K3 in Claude Code? Yes. Claude Code talks the Anthropic Messages format, which SeedRouter serves for Kimi K3. The [coding tools guide](https://seedrouter.ai/blog/kimi-k3-claude-code-codex) shows the setup. ### Which is cheapest for long documents? Kimi K3: its input rate is the lowest of the three at list price, and cached input costs a tenth of that. ### Where can I compare the live prices? On the [Kimi K3](https://seedrouter.ai/models/kimi-k3#pricing), [Claude Opus 5.5](https://seedrouter.ai/models/claude-opus-5-5#pricing) and [Claude Fable 5](https://seedrouter.ai/models/claude-fable-5#pricing) pages.