Model comparison
Claude Sonnet 5 vs Kimi K2.5 (Reasoning)
Head-to-head evidence from 18 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Sonnet 5 #29 (Estimated); Kimi K2.5 (Reasoning) #57 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Sonnet 5 and Kimi K2.5 (Reasoning) share 18 comparable benchmark results. 4 of 8 categories are comparable. 18 results are unique to Claude Sonnet 5; 9 to Kimi K2.5 (Reasoning).
Updated July 23, 2026- Shared results
- 18
- Claude Sonnet 5 only
- 18
- Kimi K2.5 (Reasoning) only
- 9
- Comparable categories
- 4 / 8
Pick Claude Sonnet 5 if you want the stronger benchmark profile. Kimi K2.5 (Reasoning) only becomes the better choice if knowledge is the priority or you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 18 shared benchmark results across 5 evidence categories; 4 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Claude Sonnet 5 is clearly ahead on the BenchAlign aggregate, 65.32 to 59.35. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Sonnet 5's sharpest advantage is in agentic, where it averages 81.9 against 55. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 80.4% to 50.8%. Kimi K2.5 (Reasoning) does hit back in knowledge, so the answer changes if that is the part of the workload you care about most.
Claude Sonnet 5 is also the more expensive model on tokens at $2.00 input / $10.00 output per 1M tokens, versus $0.60 input / $3.00 output per 1M tokens for Kimi K2.5 (Reasoning). That is roughly 3.3x on output cost alone. Claude Sonnet 5 gives you the larger context window at 1M, compared with 128K for Kimi K2.5 (Reasoning).
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | Claude Sonnet 5 | Δ | Kimi K2.5 (Reasoning) |
|---|---|---|---|
| Knowledge | Claude Sonnet 557.4 | Margin→ 29.8 | Kimi K2.5 (Reasoning)87.2 |
| Agentic | Claude Sonnet 581.9 | Margin← 26.9 | Kimi K2.5 (Reasoning)55.0 |
| Multimodal | Claude Sonnet 588.3 | Margin← 9.8 | Kimi K2.5 (Reasoning)78.5 |
| Coding | Claude Sonnet 576.7 | Margin→ 0.1 | Kimi K2.5 (Reasoning)76.8 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
Terminal-Bench 2.0
AgenticA 80.4%B 50.8%Winner: Claude Sonnet 5Δ 29.6Terminal-Bench 2.0: Claude Sonnet 5 scored 80.4%; Kimi K2.5 (Reasoning) scored 50.8%. Claude Sonnet 5 wins this benchmark. - Source ↗
BrowseComp
AgenticA 84.7%B 60.6%Winner: Claude Sonnet 5Δ 24.1BrowseComp: Claude Sonnet 5 scored 84.7%; Kimi K2.5 (Reasoning) scored 60.6%. Claude Sonnet 5 wins this benchmark. - Source ↗
SWE-bench Verified
CodingA 85.2%B 76.8%Winner: Claude Sonnet 5Δ 8.4SWE-bench Verified: Claude Sonnet 5 scored 85.2%; Kimi K2.5 (Reasoning) scored 76.8%. Claude Sonnet 5 wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude Sonnet 5 | Kimi K2.5 (Reasoning) | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Sonnet 5$2 input / $10 output | Kimi K2.5 (Reasoning)$0.6 input / $3 output | Kimi K2.5 (Reasoning) has the lower combined listed price. |
| Generation speedtokens per second | Claude Sonnet 5Not available | Kimi K2.5 (Reasoning)Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Sonnet 5Not available | Kimi K2.5 (Reasoning)Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Sonnet 51M | Kimi K2.5 (Reasoning)128K | Claude Sonnet 5 lists the larger context window. |
Benchmark Deep Dive
AgenticClaude Sonnet 5 wins16 benchmarks
| Benchmark | Claude Sonnet 5 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 80.4% | 50.8% | Claude Sonnet 5 leads |
| BrowseCompSource | 84.7% | 60.6% | Claude Sonnet 5 leads |
| HLE w/ toolsSource | 57.4% | — | Not comparable |
| OSWorld-VerifiedSource | 81.2% | — | Not comparable |
| GDPval-AASource | 1607 | 1009 | Claude Sonnet 5 leads |
| AA Agentic IndexSource | 46.7% | 21.7% | Claude Sonnet 5 leads |
| GDPval-AASource | 55.4% | 25.4% | Claude Sonnet 5 leads |
| AA BriefcaseSource | 1388 | — | Not comparable |
| AA AutomationBenchSource | 39.2% | — | Not comparable |
| AA EnterpriseOps-GymSource | 44.7% | — | Not comparable |
| AA Harvey LABSource | 90.1% | — | Not comparable |
| AA Tau3 BankingSource | 28.2% | — | Not comparable |
| aaTerminalBench21Source | 80.5% | — | Not comparable |
| APEX-Agents-AASource | — | 11.5% | Not comparable |
| τ²-bench resultsSource | — | 95.9% | Not comparable |
| Gert LabsSource | — | 32.58% | Not comparable |
CodingKimi K2.5 (Reasoning) wins10 benchmarks
| Benchmark | Claude Sonnet 5 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 85.2% | 76.8% | Claude Sonnet 5 leads |
| SWE-bench ProSource | 63.2% | — | Not comparable |
| SWE MultilingualSource | 78.3% | — | Not comparable |
| SWE MultimodalSource | 28.1% | — | Not comparable |
| Terminal-Bench 2.0Source | 80.4% | — | Not comparable |
| FrontierCode 1.1 MainSource | 42.7% | — | Not comparable |
| cursorBench32Source | 61.5% | — | Not comparable |
| AA Coding IndexSource | 71.5% | 46.8% | Claude Sonnet 5 leads |
| AA-SciCodeSource | 53.6% | 49.0% | Claude Sonnet 5 leads |
| Vibe Code BenchSource | — | 17.54% | Not comparable |
Reasoning2 benchmarks
KnowledgeKimi K2.5 (Reasoning) wins10 benchmarks
| Benchmark | Claude Sonnet 5 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| HLESource | 57.4% | — | Not comparable |
| HLE w/o toolsSource | 43.2% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 53.4% | 35.4% | Claude Sonnet 5 leads |
| AA-GPQA DiamondSource | 91.1% | 87.9% | Claude Sonnet 5 leads |
| AA-HLESource | 39.6% | 29.4% | Claude Sonnet 5 leads |
| AA-Omniscience IndexSource | 15.3% | -8.1% | Claude Sonnet 5 leads |
| AA-Omniscience AccuracySource | 38.3% | 34.3% | Claude Sonnet 5 leads |
| AA-Omniscience Hallucination RateSource | 37.3% | 64.6% | Claude Sonnet 5 leads |
| GPQASource | — | 87.6% | Not comparable |
| MMLU-ProSource | — | 87.1% | Not comparable |
Math1 benchmarks
| Benchmark | Claude Sonnet 5 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| AIME 2025Source | — | 96.1% | Not comparable |
MultimodalClaude Sonnet 5 wins5 benchmarks
Inst. Following1 benchmarks
| Benchmark | Claude Sonnet 5 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 70.2% | Not comparable |
Frequently Asked Questions (5)
Which is better, Claude Sonnet 5 or Kimi K2.5 (Reasoning)?
Claude Sonnet 5 is ahead on BenchLM's BenchAlign leaderboard, 65.32 to 59.35. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 80.4% and 50.8%.
Which is better for knowledge tasks, Claude Sonnet 5 or Kimi K2.5 (Reasoning)?
Kimi K2.5 (Reasoning) has the edge for knowledge tasks in this comparison, averaging 87.2 versus 57.4. Inside this category, AA-Omniscience Hallucination Rate is the benchmark that creates the most daylight between them.
Which is better for coding, Claude Sonnet 5 or Kimi K2.5 (Reasoning)?
Kimi K2.5 (Reasoning) has the edge for coding in this comparison, averaging 76.8 versus 76.7. Inside this category, AA Coding Index is the benchmark that creates the most daylight between them.
Which is better for agentic tasks, Claude Sonnet 5 or Kimi K2.5 (Reasoning)?
Claude Sonnet 5 has the edge for agentic tasks in this comparison, averaging 81.9 versus 55. Inside this category, GDPval-AA is the benchmark that creates the most daylight between them.
Which is better for multimodal and grounded tasks, Claude Sonnet 5 or Kimi K2.5 (Reasoning)?
Claude Sonnet 5 has the edge for multimodal and grounded tasks in this comparison, averaging 88.3 versus 78.5. Inside this category, Design Arena Website is the benchmark that creates the most daylight between them.
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