Model comparison
GPT-4.1 nano vs Kimi K2.5 (Reasoning)
Head-to-head evidence from 18 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-4.1 nano #170 (Estimated); Kimi K2.5 (Reasoning) #63 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-4.1 nano and Kimi K2.5 (Reasoning) share 18 comparable benchmark results. 1 of 8 categories are comparable. 3 results are unique to GPT-4.1 nano; 9 to Kimi K2.5 (Reasoning).
Updated July 24, 2026- Shared results
- 18
- GPT-4.1 nano only
- 3
- Kimi K2.5 (Reasoning) only
- 9
- Comparable categories
- 1 / 8
Pick Kimi K2.5 (Reasoning) if you want the stronger benchmark profile. GPT-4.1 nano only becomes the better choice if you want the cheaper token bill or you need the larger 1M context window.
Confidence note. This is a partial-evidence comparison with 18 shared benchmark results across 6 evidence categories; 1 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, 58.61 to 41.14. 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 knowledge, where it averages 87.2 against 50.3. The single biggest benchmark swing on the page is GPQA, 50.3% to 87.6%.
Kimi K2.5 (Reasoning) is also the more expensive model on tokens at $0.60 input / $3.00 output per 1M tokens, versus $0.10 input / $0.40 output per 1M tokens for GPT-4.1 nano. That is roughly 7.5x on output cost alone. Kimi K2.5 (Reasoning) is the reasoning model in the pair, while GPT-4.1 nano is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. GPT-4.1 nano 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 | GPT-4.1 nano | Δ | Kimi K2.5 (Reasoning) |
|---|---|---|---|
| Knowledge | GPT-4.1 nano50.3 | Margin→ 36.9 | Kimi K2.5 (Reasoning)87.2 |
| Agentic | GPT-4.1 nanoNot measured | MarginNo overlap | Kimi K2.5 (Reasoning)55.0 |
| Coding | GPT-4.1 nanoNot measured | MarginNo overlap | Kimi K2.5 (Reasoning)76.8 |
| Math | GPT-4.1 nano1.0 | MarginNo overlap | Kimi K2.5 (Reasoning)Not measured |
| Multimodal | GPT-4.1 nanoNot measured | MarginNo overlap | Kimi K2.5 (Reasoning)78.5 |
| Inst. Following | GPT-4.1 nano83.2 | MarginNo overlap | Kimi K2.5 (Reasoning)Not measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
GPQA
KnowledgeA 50.3%B 87.6%Winner: Kimi K2.5 (Reasoning)Δ 37.3GPQA: GPT-4.1 nano scored 50.3%; Kimi K2.5 (Reasoning) scored 87.6%. 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 | GPT-4.1 nano | Kimi K2.5 (Reasoning) | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-4.1 nano$0.1 input / $0.4 output | Kimi K2.5 (Reasoning)$0.6 input / $3 output | GPT-4.1 nano has the lower combined listed price. |
| Generation speedtokens per second | GPT-4.1 nano181 tok/s | Kimi K2.5 (Reasoning)Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-4.1 nano0.63 s | Kimi K2.5 (Reasoning)Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-4.1 nano1M | Kimi K2.5 (Reasoning)128K | GPT-4.1 nano lists the larger context window. |
Benchmark Deep Dive
Agentic8 benchmarks
| Benchmark | GPT-4.1 nano | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| AA Agentic IndexSource | 1.2% | 21.7% | Kimi K2.5 (Reasoning) leads |
| τ²-bench resultsSource | 17.3% | 95.9% | Kimi K2.5 (Reasoning) leads |
| GDPval-AASource | 0.0% | 25.1% | Kimi K2.5 (Reasoning) leads |
| GDPval-AASource | 63 | 1003 | Kimi K2.5 (Reasoning) leads |
| Terminal-Bench 2.0Source | — | 50.8% | Not comparable |
| BrowseCompSource | — | 60.6% | Not comparable |
| APEX-Agents-AASource | — | 11.5% | Not comparable |
| Gert LabsSource | — | 32.58% | Not comparable |
Coding4 benchmarks
Reasoning2 benchmarks
KnowledgeKimi K2.5 (Reasoning) wins9 benchmarks
| Benchmark | GPT-4.1 nano | Kimi K2.5 (Reasoning) | Result |
|---|---|---|---|
| MMLUSource | 80.1% | — | Not comparable |
| GPQASource | 50.3% | 87.6% | Kimi K2.5 (Reasoning) leads |
| Artificial Analysis Intelligence IndexSource | 9.6% | 35.4% | Kimi K2.5 (Reasoning) leads |
| AA-GPQA DiamondSource | 51.2% | 87.9% | Kimi K2.5 (Reasoning) leads |
| AA-HLESource | 3.9% | 29.4% | Kimi K2.5 (Reasoning) leads |
| AA-Omniscience IndexSource | -56.4% | -8.1% | Kimi K2.5 (Reasoning) leads |
| AA-Omniscience AccuracySource | 13.3% | 34.3% | Kimi K2.5 (Reasoning) leads |
| AA-Omniscience Hallucination RateSource | 80.4% | 64.6% | Kimi K2.5 (Reasoning) leads |
| MMLU-ProSource | — | 87.1% | Not comparable |
Math2 benchmarks
Multimodal3 benchmarks
Frequently Asked Questions (2)
Which is better, GPT-4.1 nano or Kimi K2.5 (Reasoning)?
Kimi K2.5 (Reasoning) is ahead on BenchLM's BenchAlign leaderboard, 58.61 to 41.14. The biggest single separator in this matchup is GPQA, where the scores are 50.3% and 87.6%.
Which is better for knowledge tasks, GPT-4.1 nano or Kimi K2.5 (Reasoning)?
Kimi K2.5 (Reasoning) has the edge for knowledge tasks in this comparison, averaging 87.2 versus 50.3. Inside this category, AA-Omniscience Index is the benchmark that creates the most daylight between them.