Model comparison
Gemini 3.1 Flash-Lite vs Grok 4.20
Head-to-head evidence from 3 shared benchmark results across 3 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Gemini 3.1 Flash-Lite #114 (Supported); Grok 4.20 #93 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Gemini 3.1 Flash-Lite and Grok 4.20 share 3 comparable benchmark results. 1 of 8 categories are comparable. 17 results are unique to Gemini 3.1 Flash-Lite; 16 to Grok 4.20.
Updated July 28, 2026- Shared results
- 3
- Gemini 3.1 Flash-Lite only
- 17
- Grok 4.20 only
- 16
- Comparable categories
- 1 / 8
Pick Grok 4.20 if you want the stronger benchmark profile. Gemini 3.1 Flash-Lite only becomes the better choice if multimodal & grounded is the priority or you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 3 shared benchmark results across 3 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
Grok 4.20 is clearly ahead on the BenchAlign aggregate, 53.88 to 50.18. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Grok 4.20 is also the more expensive model on tokens at $2.00 input / $6.00 output per 1M tokens, versus $0.25 input / $1.50 output per 1M tokens for Gemini 3.1 Flash-Lite. That is roughly 4.0x on output cost alone. Grok 4.20 is the reasoning model in the pair, while Gemini 3.1 Flash-Lite 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. Grok 4.20 gives you the larger context window at 2M, compared with 1M for Gemini 3.1 Flash-Lite.
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 | Gemini 3.1 Flash-Lite | Δ | Grok 4.20 |
|---|---|---|---|
| Multimodal | Gemini 3.1 Flash-Lite73.2 | Margin← 3.1 | Grok 4.2070.1 |
| Agentic | Gemini 3.1 Flash-LiteNot measured | MarginNo overlap | Grok 4.2047.1 |
| Coding | Gemini 3.1 Flash-LiteNot measured | MarginNo overlap | Grok 4.2067.1 |
| Reasoning | Gemini 3.1 Flash-LiteNot measured | MarginNo overlap | Grok 4.2053.3 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
CharXiv
MultimodalA 73.2%B 60.9%Winner: Gemini 3.1 Flash-LiteΔ 12.3CharXiv: Gemini 3.1 Flash-Lite scored 73.2%; Grok 4.20 scored 60.9%. Gemini 3.1 Flash-Lite wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Gemini 3.1 Flash-Lite | Grok 4.20 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Gemini 3.1 Flash-Lite$0.25 input / $1.5 output | Grok 4.20$2 input / $6 output | Gemini 3.1 Flash-Lite has the lower combined listed price. |
| Generation speedtokens per second | Gemini 3.1 Flash-Lite205 tok/s | Grok 4.20233 tok/s | Grok 4.20 has the higher measured throughput. |
| First-answer latencyseconds to first token | Gemini 3.1 Flash-Lite7.50 s | Grok 4.2010.33 s | Gemini 3.1 Flash-Lite reaches the first token sooner. |
| Context windowmaximum listed tokens | Gemini 3.1 Flash-Lite1M | Grok 4.202M | Grok 4.20 lists the larger context window. |
Benchmark Deep Dive
Agentic8 benchmarks
| Benchmark | Gemini 3.1 Flash-Lite | Grok 4.20 | Result |
|---|---|---|---|
| AA Agentic IndexSource | 6.2% | — | Not comparable |
| APEX-Agents-AASource | 12.2% | — | Not comparable |
| τ²-bench resultsSource | 31.3% | — | Not comparable |
| GDPval-AASource | 7.3% | — | Not comparable |
| GDPval-AASource | 647 | — | Not comparable |
| Gert LabsSource | 38.46% | 38.36% | Gemini 3.1 Flash-Lite leads |
| Terminal-Bench 2.0Source | — | 47.1% | Not comparable |
| DeepSearchQASource | — | 62.8% | Not comparable |
Coding6 benchmarks
| Benchmark | Gemini 3.1 Flash-Lite | Grok 4.20 | Result |
|---|---|---|---|
| Vibe Code BenchSource | 0.00% | 4.06% | Grok 4.20 leads |
| AA Coding IndexSource | 34.7% | — | Not comparable |
| AA-SciCodeSource | 41.9% | — | Not comparable |
| LiveCodeBench ProSource | — | 74.2% | Not comparable |
| SWE-bench VerifiedSource | — | 76.7% | Not comparable |
| SWE-bench ProSource | — | 51.8% | Not comparable |
Reasoning4 benchmarks
Knowledge10 benchmarks
| Benchmark | Gemini 3.1 Flash-Lite | Grok 4.20 | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 25.0% | — | Not comparable |
| AA-GPQA DiamondSource | 82.2% | — | Not comparable |
| AA-HLESource | 16.2% | — | Not comparable |
| AA-Omniscience IndexSource | -15.5% | — | Not comparable |
| AA-Omniscience AccuracySource | 36.4% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 81.6% | — | Not comparable |
| 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 |
MultimodalGemini 3.1 Flash-Lite wins7 benchmarks
| Benchmark | Gemini 3.1 Flash-Lite | Grok 4.20 | Result |
|---|---|---|---|
| CharXivSource | 73.2% | 60.9% | Gemini 3.1 Flash-Lite leads |
| AA-MMMU-ProSource | 75.5% | — | Not comparable |
| MMMU-ProSource | — | 75.2% | Not comparable |
| ERQASource | — | 54.1% | Not comparable |
| SimpleVQASource | — | 57.4% | Not comparable |
| MedXpertQA (MM)Source | — | 65.8% | Not comparable |
| Design Arena WebsiteSource | — | 1252 | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Gemini 3.1 Flash-Lite | Grok 4.20 | Result |
|---|---|---|---|
| AA-IFBenchSource | 77.2% | — | Not comparable |
Frequently Asked Questions (2)
Which is better, Gemini 3.1 Flash-Lite or Grok 4.20?
Grok 4.20 is ahead on BenchLM's BenchAlign leaderboard, 53.88 to 50.18. The biggest single separator in this matchup is CharXiv, where the scores are 73.2% and 60.9%.
Which is better for multimodal and grounded tasks, Gemini 3.1 Flash-Lite or Grok 4.20?
Gemini 3.1 Flash-Lite has the edge for multimodal and grounded tasks in this comparison, averaging 73.2 versus 70.1. Inside this category, CharXiv is the benchmark that creates the most daylight between them.
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