Released July 16, 2026; open weights July 26. Cache-hit input $0.30/1M. Subscriptions: Adagio (free) to Vivace $199/mo; full 1M context only on Allegro ($99) and up. New signups paused July 19 near GPU capacity, reopening in batches.
Open weights (July 26, 2026) — at 2.8T parameters, the largest open-weight release in history
Weaknesses
Most expensive Chinese-lab model ever ($3/$15) with always-on thinking driving high output-token burn and slow responses
2.8T size makes self-hosting impractical despite open weights; consumer signups were paused July 19 over GPU capacity
Real-world use cases
What people actually use Kimi K3 for.
Hardest reasoning tasks — #4 of all models on AA Intelligence Index v4.1 (57.1), ahead of Claude Opus 4.8
Agentic coding at 81.2 FrontierSWE and 88.3 Terminal-Bench 2.0 (Moonshot-reported)
1M-context research synthesis with always-on extended thinking
How Kimi K3 compares
The nearest models people weigh against it, and what actually separates them.
vs Claude Fable 5 — Against Claude Fable 5 (Anthropic), Kimi K3 runs about 70% cheaper per token. Take Kimi K3 unless you specifically need what Claude Fable 5 does better.
vs Claude Fable 5.1 — Against Claude Fable 5.1 (Anthropic), Kimi K3 runs about 70% cheaper per token. Take Kimi K3 unless you specifically need what Claude Fable 5.1 does better.
vs Claude Opus 4.7 — Against Claude Opus 4.7 (Anthropic), Kimi K3 runs about 40% cheaper per token. Take Kimi K3 unless you specifically need what Claude Opus 4.7 does better.
Price History
Kimi K3 pricing over time
→0% since Aug 7
38 data points · tracked daily since Aug 7, 2026
Ready to try it?
Start using Kimi K3
Frontier-level reasoning and agentic coding. Start free — no card required.
Anthropic's new Mythos-class flagship and the most capable coding model anyone can use — 80.3% SWE-Bench Pro, an 11-point jump over Opus 4.8. 1M context, 128K output, native parallel subagents. Released June 9, 2026.
Verdict
New global #1 — 80.3% SWE-Bench Pro, the most capable model generally available.
Quality score
98%
Pricing
$10.00/1M in
$50.00/1M out
Speed
Deliberate
2/5 speed
Context
1M tokens
Launched June 9, 2026 as the public, Mythos-class release. Available on the Claude API, Microsoft Foundry, and Google Vertex AI. Free for all users until June 22, 2026. Same underlying model as Claude Mythos 5, with safeguards that block specific high-risk cyber responses.
Coding leaderSWE-Bench Pro #1Mythos-classParallel subagentsAgenticLong contextPremiumNew
Best for
The hardest coding tasks, autonomous multi-step agents, and frontier-grade reasoning
Anthropic's September 1, 2026 frontier release and the new capability ceiling for coding, agents, and scientific work. Base pricing is unchanged at $10/$50, but cache reads dropped 75% to $0.25/1M — roughly 25% cheaper on typical workloads and up to 45% cheaper on agentic ones. 1M context, 128K output, adaptive thinking always on.
Verdict
New frontier leader — better than Fable 5 on every published benchmark, and cheaper to run.
Quality score
98%
Pricing
$10.00/1M in
$50.00/1M out
Speed
Deliberate
2/5 speed
Context
1M tokens
Released September 1, 2026 alongside Claude Mythos 5.1, the first update to the Mythos-class line since Fable 5 on June 9. API ID claude-fable-5-1; generally available on the Claude API, Amazon Bedrock, Google Cloud, and Microsoft Foundry. Published launch numbers (Fable 5.1 / Fable 5 / Opus 5 / GPT-5.6 Sol): Terminal-Bench-Science 0.1 52.6 / 24.7 / 29.0 / 22.4; Terminal-Bench 4.0 55.8 / 42.0 / 52.3 / 37.3; CursorBench 3.2.0 73.4 / 70.5 / 70.0 / 67.2; AutomationBench 31.4 / 17.1 / 26.9 / 19.6; OSWorld 2.0 strict 41.7 / 36.1 / 39.6; Humanity's Last Exam (no tools) 60.9 / 57.8 / 56.6; GDPval-AA v2 1853 / 1723 / 1824 / 1711. GDPval-AA v2 is rescaled from the v1 numbers quoted on the Fable 5 page and is not directly comparable to them.
Kimi K3 costs $3 per million input tokens and $15 per million output tokens on the API, with cached input at $0.3 per million. A month of 10M input and 2M output tokens runs about $60.00 at list price, before any batch or caching discounts.
What is the context window of Kimi K3?
Kimi K3 has a 1M tokens context window, with up to 131k tokens of output per response. That is the total of prompt plus response the model can hold in one request.
What is Kimi K3 best for?
Kimi K3 is best for frontier-level reasoning and agentic coding. It is a strong fit when that workflow matters more than the tradeoffs around premium pricing and deliberate speed.
When should I avoid Kimi K3?
You need fast responses or predictable output costs — always-on thinking burns tokens.
What is a cheaper alternative to Kimi K3?
GPT-5.1-Codex-Max (OpenAI) at $1.25/1M/1M input against Kimi K3's $3.00/1M/1M — roughly 38% less per token all in. The strongest choice for serious software engineering work, provided you can absorb the output-side pricing. Compare it first if Kimi K3's pricing is the thing stopping you.
What is a faster alternative to Kimi K3?
Claude Fable 5 — deliberate against Kimi K3's deliberate, with 1M tokens of context. Worth the swap when response time is what your users notice rather than the last few points of reasoning depth.
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