Model comparison
Grok 4.20 vs Kimi K2.5 (Reasoning)
Head-to-head evidence from 6 shared benchmark results across 3 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Grok 4.20 #93 (Estimated); Kimi K2.5 (Reasoning) #64 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Grok 4.20 and Kimi K2.5 (Reasoning) share 6 comparable benchmark results. 3 of 8 categories are comparable. 13 results are unique to Grok 4.20; 21 to Kimi K2.5 (Reasoning).
Updated July 28, 2026- Shared results
- 6
- Grok 4.20 only
- 13
- Kimi K2.5 (Reasoning) only
- 21
- Comparable categories
- 3 / 8
Pick Kimi K2.5 (Reasoning) if you want the stronger benchmark profile. Grok 4.20 only becomes the better choice if you need the larger 2M context window.
Confidence note. This is a partial-evidence comparison with 6 shared benchmark results across 3 evidence categories; 3 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Kimi K2.5 (Reasoning) is clearly ahead on the BenchAlign aggregate, 58.53 to 53.88. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Kimi K2.5 (Reasoning)'s sharpest advantage is in coding, where it averages 76.8 against 67.1. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 47.1% to 50.8%.
Grok 4.20 is also the more expensive model on tokens at $2.00 input / $6.00 output per 1M tokens, versus $0.60 input / $3.00 output per 1M tokens for Kimi K2.5 (Reasoning). That is roughly 2.0x on output cost alone. Grok 4.20 gives you the larger context window at 2M, 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 | Grok 4.20 | Δ | Kimi K2.5 (Reasoning) |
|---|---|---|---|
| Coding | Grok 4.2067.1 | Margin→ 9.7 | Kimi K2.5 (Reasoning)76.8 |
| Multimodal | Grok 4.2070.1 | Margin→ 8.4 | Kimi K2.5 (Reasoning)78.5 |
| Agentic | Grok 4.2047.1 | Margin→ 7.9 | Kimi K2.5 (Reasoning)55.0 |
| Reasoning | Grok 4.2053.3 | MarginNo overlap | Kimi K2.5 (Reasoning)Not measured |
| Knowledge | Grok 4.20Not measured | MarginNo overlap | Kimi K2.5 (Reasoning)87.2 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
Terminal-Bench 2.0
AgenticA 47.1%B 50.8%Winner: Kimi K2.5 (Reasoning)Δ 3.7Terminal-Bench 2.0: Grok 4.20 scored 47.1%; Kimi K2.5 (Reasoning) scored 50.8%. Kimi K2.5 (Reasoning) wins this benchmark. - Source ↗
MMMU-Pro
MultimodalA 75.2%B 78.5%Winner: Kimi K2.5 (Reasoning)Δ 3.3MMMU-Pro: Grok 4.20 scored 75.2%; Kimi K2.5 (Reasoning) scored 78.5%. Kimi K2.5 (Reasoning) wins this benchmark. - Source ↗
SWE-bench Verified
CodingA 76.7%B 76.8%Winner: Kimi K2.5 (Reasoning)Δ 0.1SWE-bench Verified: Grok 4.20 scored 76.7%; Kimi K2.5 (Reasoning) scored 76.8%. Kimi K2.5 (Reasoning) wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Grok 4.20 | Kimi K2.5 (Reasoning) | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Grok 4.20$2 input / $6 output | Kimi K2.5 (Reasoning)$0.6 input / $3 output | Kimi K2.5 (Reasoning) has the lower combined listed price. |
| Generation speedtokens per second | Grok 4.20233 tok/s | Kimi K2.5 (Reasoning)Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Grok 4.2010.33 s | Kimi K2.5 (Reasoning)Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Grok 4.202M | Kimi K2.5 (Reasoning)128K | Grok 4.20 lists the larger context window. |
Benchmark Deep Dive
AgenticKimi K2.5 (Reasoning) wins9 benchmarks
| Benchmark | Grok 4.20 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 47.1% | 50.8% | Kimi K2.5 (Reasoning) leads |
| DeepSearchQASource | 62.8% | — | Not comparable |
| Gert LabsSource | 38.36% | 32.58% | Grok 4.20 leads |
| BrowseCompSource | — | 60.6% | Not comparable |
| APEX-Agents-AASource | — | 11.5% | Not comparable |
| τ²-bench resultsSource | — | 95.9% | Not comparable |
| AA Agentic IndexSource | — | 21.7% | Not comparable |
| GDPval-AASource | — | 25.1% | Not comparable |
| GDPval-AASource | — | 1003 | Not comparable |
CodingKimi K2.5 (Reasoning) wins6 benchmarks
| Benchmark | Grok 4.20 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| LiveCodeBench ProSource | 74.2% | — | Not comparable |
| SWE-bench VerifiedSource | 76.7% | 76.8% | Kimi K2.5 (Reasoning) leads |
| SWE-bench ProSource | 51.8% | — | Not comparable |
| Vibe Code BenchSource | 4.06% | 17.54% | Kimi K2.5 (Reasoning) leads |
| AA-SciCodeSource | — | 49.0% | Not comparable |
| AA Coding IndexSource | — | 46.8% | Not comparable |
Reasoning4 benchmarks
Knowledge12 benchmarks
| Benchmark | Grok 4.20 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| GPQA-DSource | 88.5% | — | Not comparable |
| HLE w/o toolsSource | 31.6% | — | Not comparable |
| HealthBench HardSource | 20.3% | — | Not comparable |
| MedXpertQA (Text)Source | 50.2% | — | Not comparable |
| GPQASource | — | 87.6% | Not comparable |
| MMLU-ProSource | — | 87.1% | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 35.4% | Not comparable |
| AA-GPQA DiamondSource | — | 87.9% | Not comparable |
| AA-HLESource | — | 29.4% | Not comparable |
| AA-Omniscience IndexSource | — | -8.1% | Not comparable |
| AA-Omniscience AccuracySource | — | 34.3% | Not comparable |
| AA-Omniscience Hallucination RateSource | — | 64.6% | Not comparable |
Math1 benchmarks
| Benchmark | Grok 4.20 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| AIME 2025Source | — | 96.1% | Not comparable |
MultimodalKimi K2.5 (Reasoning) wins7 benchmarks
| Benchmark | Grok 4.20 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| MMMU-ProSource | 75.2% | 78.5% | Kimi K2.5 (Reasoning) leads |
| CharXivSource | 60.9% | — | Not comparable |
| ERQASource | 54.1% | — | Not comparable |
| SimpleVQASource | 57.4% | — | Not comparable |
| MedXpertQA (MM)Source | 65.8% | — | Not comparable |
| Design Arena WebsiteSource | 1252 | 1275 | Kimi K2.5 (Reasoning) leads |
| AA-MMMU-ProSource | — | 75.4% | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Grok 4.20 | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 70.2% | Not comparable |
Frequently Asked Questions (4)
Which is better, Grok 4.20 or Kimi K2.5 (Reasoning)?
Kimi K2.5 (Reasoning) is ahead on BenchLM's BenchAlign leaderboard, 58.53 to 53.88. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 47.1% and 50.8%.
Which is better for coding, Grok 4.20 or Kimi K2.5 (Reasoning)?
Kimi K2.5 (Reasoning) has the edge for coding in this comparison, averaging 76.8 versus 67.1. Inside this category, Vibe Code Bench is the benchmark that creates the most daylight between them.
Which is better for agentic tasks, Grok 4.20 or Kimi K2.5 (Reasoning)?
Kimi K2.5 (Reasoning) has the edge for agentic tasks in this comparison, averaging 55 versus 47.1. Inside this category, Gert Labs is the benchmark that creates the most daylight between them.
Which is better for multimodal and grounded tasks, Grok 4.20 or Kimi K2.5 (Reasoning)?
Kimi K2.5 (Reasoning) has the edge for multimodal and grounded tasks in this comparison, averaging 78.5 versus 70.1. Inside this category, Design Arena Website is the benchmark that creates the most daylight between them.
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