Nano Banana Pro (Gemini 3 Pro Image) vs Grok 4.20
Updated October 21, 2026. 0 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
- Coding
- No data
- Overall
- No data
- Output $/M
- $12.00
- Coding
- 33.3
- Overall
- 25.7
- Output $/M
- $2.50
Decision reading
Only Grok 4.20 has a coding score, 33.3 on the Vibe Coding Index; Nano Banana Pro (Gemini 3 Pro Image) has none, so the two cannot be ranked on coding.
Compare them on price, context and the boards below.
- Shared results
- 0
- Nano Banana Pro (Gemini 3 Pro Image) only
- 1
- Grok 4.20 only
- 54
- Like-for-like categories
- 0 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
No call
Only Grok 4.20 has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
No call
Only Grok 4.20 has a AA Intelligence Index result, 25.7.
Directional only
Reasoning
GPQA Diamond
No call
Only Grok 4.20 has a GPQA Diamond result, 88.6%.
Directional only
Math
AIME
No call
Only Grok 4.20 has a AIME result, 96.5%.
Directional only
Knowledge
MMLU Pro
No call
Only Grok 4.20 has a MMLU Pro result, 86.3%.
Directional only
Web design
Design Arena: websites
No call
Only Grok 4.20 has a Design Arena: websites result, 1229.
Directional only
Long documents
Listed context window
Grok 4.20
Grok 4.20 takes 2M tokens against 131K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Grok 4.20
Nano Banana Pro (Gemini 3 Pro Image) $0.0080, Grok 4.20 $0.0025 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Grok 4.20 has the number, $0.72.
Directional only
At a glance
- Coding index
- Nano Banana Pro (Gemini 3 Pro Image) not benchmarked, Grok 4.20 33.3 from 2 benchmarks.
- Widest category
- No category has a result for both models.
- Widest single gap
- No benchmark has a result for both models.
- Output price
- Nano Banana Pro (Gemini 3 Pro Image) $12.00 against Grok 4.20 $2.50 per million output tokens, 4.8x apart.
- Context window
- Nano Banana Pro (Gemini 3 Pro Image) takes 131K tokens, Grok 4.20 2M.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
CodingDirectional onlySix of these boards feed the Vibe Coding Index8 boards, none shared
| Benchmark | Nano Banana Pro (Gemini 3 Pro Image) | Grok 4.20 | Leader |
|---|---|---|---|
| LiveCodeBench (Vals AI) | Not measured | 84.3% | Only Grok 4.20 measured |
| SWE-bench Verified (Vals AI) | Not measured | 72.2% | Only Grok 4.20 measured |
| Vibe Code Bench (Vals AI) | Not measured | 4.1% | Only Grok 4.20 measured |
| Code migration (Vals AI) | Not measured | 0.3% | Only Grok 4.20 measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 44.2% | Only Grok 4.20 measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 37.9% | Only Grok 4.20 measured |
| Terminal-Bench | Not measured | 57.3% | Only Grok 4.20 measured |
| WeirdML | Not measured | 52.3% | Only Grok 4.20 measured |
| Neither model has a result on the other 30 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Nano Banana Pro (Gemini 3 Pro Image) | Grok 4.20 | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 25.7 | Only Grok 4.20 measured |
| Epoch Capabilities Index | Not measured | 152.1 | Only Grok 4.20 measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index12 boards, none shared
| Benchmark | Nano Banana Pro (Gemini 3 Pro Image) | Grok 4.20 | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | Not measured | 1144 | Only Grok 4.20 measured |
| Design Arena: agents building full-stack apps | Not measured | 1054 | Only Grok 4.20 measured |
| Design Arena: agents building mobile apps | Not measured | 1090 | Only Grok 4.20 measured |
| Design Arena: agents building Android apps | Not measured | 1052 | Only Grok 4.20 measured |
| Design Arena: agents building Godot games | Not measured | 1089 | Only Grok 4.20 measured |
| Design Arena: HTML slides | Not measured | 1180 | Only Grok 4.20 measured |
| Finance Agent (Vals AI) | Not measured | 28.5% | Only Grok 4.20 measured |
| Tax Agent Bench (Vals AI) | Not measured | 7.0% | Only Grok 4.20 measured |
| Legal Research Bench (Vals AI) | Not measured | 13.9% | Only Grok 4.20 measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 11.7% | Only Grok 4.20 measured |
| τ²-Bench Telecom | Not measured | 93.0% | Only Grok 4.20 measured |
| Vending-Bench 2 | Not measured | $4,663 | Only Grok 4.20 measured |
| Neither model has a result on the other 27 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index6 boards, none shared
| Benchmark | Nano Banana Pro (Gemini 3 Pro Image) | Grok 4.20 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 88.6% | Only Grok 4.20 measured |
| MMMU Pro (Vals AI) | Not measured | 83.5% | Only Grok 4.20 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 91.1% | Only Grok 4.20 measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 34.5% | Only Grok 4.20 measured |
| ARC-AGI | Not measured | 89.5% | Only Grok 4.20 measured |
| ARC-AGI-2 | Not measured | 65.1% | Only Grok 4.20 measured |
| Neither model has a result on the other 15 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | Nano Banana Pro (Gemini 3 Pro Image) | Grok 4.20 | Leader |
|---|---|---|---|
| AIME | Not measured | 96.5% | Only Grok 4.20 measured |
| Neither model has a result on the other 12 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | Nano Banana Pro (Gemini 3 Pro Image) | Grok 4.20 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 86.3% | Only Grok 4.20 measured |
| LegalBench (Vals AI) | Not measured | 77.7% | Only Grok 4.20 measured |
| CaseLaw (Vals AI) | Not measured | 54.4% | Only Grok 4.20 measured |
| CorpFin (Vals AI) | Not measured | 63.7% | Only Grok 4.20 measured |
| TaxEval (Vals AI) | Not measured | 74.1% | Only Grok 4.20 measured |
| MortgageTax (Vals AI) | Not measured | 45.4% | Only Grok 4.20 measured |
| MedQA (Vals AI) | Not measured | 94.5% | Only Grok 4.20 measured |
| MedCode (Vals AI) | Not measured | 32.2% | Only Grok 4.20 measured |
| Neither model has a result on the other 9 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | Nano Banana Pro (Gemini 3 Pro Image) | Grok 4.20 | Leader |
|---|---|---|---|
| Design Arena: websites | Not measured | 1229 | Only Grok 4.20 measured |
| Design Arena: UI components | Not measured | 1199 | Only Grok 4.20 measured |
| Design Arena: game dev | Not measured | 1192 | Only Grok 4.20 measured |
| Design Arena: data viz | Not measured | 1217 | Only Grok 4.20 measured |
| Design Arena: 3D | Not measured | 1193 | Only Grok 4.20 measured |
| Design Arena: all code categories | Not measured | 1221 | Only Grok 4.20 measured |
| Design Arena: SVG | Not measured | 1164 | Only Grok 4.20 measured |
| Design Arena: ASCII art | Not measured | 1174 | Only Grok 4.20 measured |
| Neither model has a result on the other 1 board here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared
| Benchmark | Nano Banana Pro (Gemini 3 Pro Image) | Grok 4.20 | Leader |
|---|---|---|---|
| SAGE (Vals AI) | Not measured | 38.2% | Only Grok 4.20 measured |
| MedScribe (Vals AI) | Not measured | 63.4% | Only Grok 4.20 measured |
| Vals Multimodal Index | Not measured | 39.1% | Only Grok 4.20 measured |
| IFBench | Not measured | 81.2% | Only Grok 4.20 measured |
| Long context reasoning (AA-LCR) | Not measured | 69.0% | Only Grok 4.20 measured |
| DTBench | Not measured | 90.1% | Only Grok 4.20 measured |
| LMCA | Not measured | 38.7% | Only Grok 4.20 measured |
| CL-bench | Not measured | 22.2% | Only Grok 4.20 measured |
| CL-bench Life | Not measured | 11.9% | Only Grok 4.20 measured |
| Neither model has a result on the other 37 boards here | |||
Image generationDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | Nano Banana Pro (Gemini 3 Pro Image) | Grok 4.20 | Leader |
|---|---|---|---|
| LMArena Image Edit | 1390 | Not measured | Only Nano Banana Pro (Gemini 3 Pro Image) measured |
| Neither model has a result on the other 4 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Grok 4.20 costs less
Repository review
50K input + 3K output tokens
Grok 4.20 costs less
Agent loop
200K input + 10K output tokens
Grok 4.20 costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | Google Nano Banana Pro (Gemini 3 Pro Image) | SpaceXAI Grok 4.20 |
|---|---|---|
| Maker | xAI | |
| Weights | No public weights listed | No public weights listed |
| Released | June 18, 2026 | March 31, 2026 |
| Context window | 131K | 2M |
| Input $/Mtok | $2.00 | $1.25 |
| Output $/Mtok | $12.00 | $2.50 |
| Coding index | Not benchmarked | 33.3 |
| Independent measurements behind it | 0 | 2 |
| Cost per solved task | Not computable | $0.72 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Nano Banana Pro (Gemini 3 Pro Image) better than Grok 4.20 for coding?
Only Grok 4.20 has a coding score, 33.3 on the Vibe Coding Index; Nano Banana Pro (Gemini 3 Pro Image) has none, so the two cannot be ranked on coding. Compare them on price, context and the boards below.
Which is cheaper, Nano Banana Pro (Gemini 3 Pro Image) or Grok 4.20?
Nano Banana Pro (Gemini 3 Pro Image) costs $2.00 per million input tokens and $12.00 per million output tokens; Grok 4.20 costs $1.25 and $2.50. Cost per solved task is known for Grok 4.20 only.
Which has the bigger context window, Nano Banana Pro (Gemini 3 Pro Image) or Grok 4.20?
Grok 4.20, with 2M tokens against 131K.
How many benchmarks is the Nano Banana Pro (Gemini 3 Pro Image) vs Grok 4.20 comparison based on?
0 benchmarks have a result for both models as of October 21, 2026. Nano Banana Pro (Gemini 3 Pro Image)'s coding index rests on 0 independent benchmarks and Grok 4.20's on 2. Where only one model has a result, the page says so instead of naming a winner.