Claude Sonnet 4.6 vs Kimi K2: Benchmarks, Pricing & Capabilities Compared
TL;DR — Claude Sonnet 4.6 wins for coding + reasoning · Kimi K2 wins for cost + long-context.
Claude Sonnet 4.6 Anthropic
- Released
- 2026-02-17
- Context window
- 500K tokens
- Input price
- $3.00 / Mtok
- Output price
- $15.00 / Mtok
Key features
- Agent Teams: orchestrate 2-16 Claude instances
- Near-Opus performance at 1/5th cost
- 80.8% SWE-bench Verified
Kimi K2 Moonshot AI
- Released
- 2026-01-20
- Context window
- 2M tokens
- Input price
- $0.15 / Mtok
- Output price
- $2.50 / Mtok
Key features
- First open-weight model #1 on LMSYS Chatbot Arena
- 1.04 trillion parameters
- K2.5 agent swarms with up to 100 sub-agents
Benchmark comparison
| Benchmark | Claude Sonnet 4.6 | Kimi K2 |
|---|---|---|
| GPQA Diamond | 78.4% ✓ | 74.1% |
| MMLU | 92.1% ✓ | 91.3% |
| SWE-bench Verified | 80.8% ✓ | 65.8% |
Pricing comparison
| Metric | Claude Sonnet 4.6 | Kimi K2 |
|---|---|---|
| Input ($/Mtok) | $3.00 | $0.15 |
| Output ($/Mtok) | $15.00 | $2.50 |
| Cached input ($/Mtok) | $0.30 | — |
| Cost per 1M-token roundtrip (1M in + 1M out) | $18.00 | $2.65 |
Context window & modalities
| Attribute | Claude Sonnet 4.6 | Kimi K2 |
|---|---|---|
| Context window | 500K tokens | 2M tokens |
| Input modalities | text, image, PDF | text, image |
| Output modalities | text | text |
| Knowledge cutoff | 2025-10 | 2025-10 |
Verdict by use case
Coding
→ Claude Sonnet 4.6
Basis: SWE-bench
Claude Sonnet 4.6 80.8% vs Kimi K2 65.8% on SWE-bench.
Reasoning
→ Claude Sonnet 4.6
Basis: GPQA Diamond
Claude Sonnet 4.6 78.4% vs Kimi K2 74.1% on GPQA Diamond.
Math
Insufficient data
Basis: MATH / AIME
No shared math benchmark.
Long context
→ Kimi K2
Basis: Context window
Claude Sonnet 4.6 500K tokens vs Kimi K2 2M tokens.
Cost
→ Kimi K2
Basis: Input $/Mtok
Claude Sonnet 4.6 $3/Mtok vs Kimi K2 $0.15/Mtok input.
Changelog & releases
Claude Sonnet 4.6
Released 2026-02-17
Predecessor: anthropic-claude-sonnet-4
- Agent Teams: orchestrate 2–16 Claude instances in parallel
- +8.5pt on SWE-bench Verified vs Sonnet 4
- 1/5 the cost of Opus 4.5 at ~95% of coding quality
- Fast mode research preview for lower-latency inference
Kimi K2
Released 2026-01-20
Predecessor: moonshot-ai-moonshot-kimi
- 2M token context window (20x vs first Kimi)
- Agentic tool-use tuning via MuonClip optimizer
- Open weights under modified MIT