Model comparison
Gemini 2.5 Flash vs Grok 4.20
Head-to-head evidence from 1 shared benchmark result across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Gemini 2.5 Flash #134 (Supported); Grok 4.20 #93 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Gemini 2.5 Flash and Grok 4.20 share 1 comparable benchmark result. 0 of 8 categories are comparable. 14 results are unique to Gemini 2.5 Flash; 18 to Grok 4.20.
Updated July 28, 2026- Shared results
- 1
- Gemini 2.5 Flash only
- 14
- Grok 4.20 only
- 18
- Comparable categories
- 0 / 8
Benchmark data for Gemini 2.5 Flash and Grok 4.20 is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 1 shared benchmark result across 1 evidence category; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
BenchLM has partial data for these models, but not enough overlapping benchmark coverage to produce a fair score-level comparison yet.
Grok 4.20 is priced at $2.00 input / $6.00 output per 1M tokens, versus $0.30 input / $2.50 output per 1M tokens for Gemini 2.5 Flash. Grok 4.20 has the larger context window at 2M, compared with 1M for Gemini 2.5 Flash.
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 2.5 Flash | Δ | Grok 4.20 |
|---|---|---|---|
| Agentic | Gemini 2.5 FlashNot measured | MarginNo overlap | Grok 4.2047.1 |
| Coding | Gemini 2.5 FlashNot measured | MarginNo overlap | Grok 4.2067.1 |
| Reasoning | Gemini 2.5 FlashNot measured | MarginNo overlap | Grok 4.2053.3 |
| Math | Gemini 2.5 Flash4.7 | MarginNo overlap | Grok 4.20Not measured |
| Multimodal | Gemini 2.5 FlashNot measured | MarginNo overlap | Grok 4.2070.1 |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Gemini 2.5 Flash | Grok 4.20 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Gemini 2.5 Flash$0.3 input / $2.5 output | Grok 4.20$2 input / $6 output | Gemini 2.5 Flash has the lower combined listed price. |
| Generation speedtokens per second | Gemini 2.5 Flash221 tok/s | Grok 4.20233 tok/s | Grok 4.20 has the higher measured throughput. |
| First-answer latencyseconds to first token | Gemini 2.5 Flash0.50 s | Grok 4.2010.33 s | Gemini 2.5 Flash reaches the first token sooner. |
| Context windowmaximum listed tokens | Gemini 2.5 Flash1M | Grok 4.202M | Grok 4.20 lists the larger context window. |
Benchmark Deep Dive
Agentic4 benchmarks
Coding5 benchmarks
Reasoning4 benchmarks
Knowledge10 benchmarks
| Benchmark | Gemini 2.5 Flash | Grok 4.20 | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 14.1% | — | Not comparable |
| AA-GPQA DiamondSource | 68.3% | — | Not comparable |
| AA-HLESource | 5.1% | — | Not comparable |
| AA-Omniscience IndexSource | -42.0% | — | Not comparable |
| AA-Omniscience AccuracySource | 26.5% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 93.3% | — | 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 |
Math2 benchmarks
Multimodal7 benchmarks
| Benchmark | Gemini 2.5 Flash | Grok 4.20 | Result |
|---|---|---|---|
| AA-MMMU-ProSource | 65.5% | — | Not comparable |
| Design Arena WebsiteSource | 1140 | 1252 | Grok 4.20 leads |
| MMMU-ProSource | — | 75.2% | Not comparable |
| CharXivSource | — | 60.9% | Not comparable |
| ERQASource | — | 54.1% | Not comparable |
| SimpleVQASource | — | 57.4% | Not comparable |
| MedXpertQA (MM)Source | — | 65.8% | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Gemini 2.5 Flash | Grok 4.20 | Result |
|---|---|---|---|
| AA-IFBenchSource | 39.0% | — | Not comparable |
Frequently Asked Questions (3)
Can I compare Gemini 2.5 Flash and Grok 4.20 on BenchLM yet?
Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.
Why does this comparison show “coming soon”?
BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.
What data is available for Gemini 2.5 Flash and Grok 4.20 today?
Gemini 2.5 Flash: $0.30 input / $2.50 output per 1M tokens Grok 4.20: $2.00 input / $6.00 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
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