High-volume, cost-sensitive work
Choose Gemini 3.6 Flash
Gemini 3.6 Flash costs 4% less on a typical mix of three input tokens for every output token ($1.50 against $1.56 per million tokens).
Gemini 3.6 Flash vs Grok 4.20 Reasoning: price, context and capabilities
Choose Gemini 3.6 Flash for high-volume, cost-sensitive work, reused prompts and documents (RAG, agents) and the latest release. Choose Grok 4.20 Reasoning for writing and code generation.
In short
- Gemini 3.6 Flash is 4% cheaper than Grok 4.20 Reasoning at the headline price ($1.50 / 1M tokens vs $1.56 / 1M tokens).
- Gemini 3.6 Flash reads more per request: 1.05M tokens against 1M.
- Gemini 3.6 Flash is the newer model (July 2026, against March 2026).
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Writing and code generation
Choose Grok 4.20 Reasoning
Grok 4.20 Reasoning charges $2.50 per million output tokens, against $3.75 for Gemini 3.6 Flash. Output dominates the bill when answers are long.
Reused prompts and documents (RAG, agents)
Choose Gemini 3.6 Flash
Gemini 3.6 Flash charges $0.08 per million cached input tokens, against $0.20 for Grok 4.20 Reasoning.
Latest release
Choose Gemini 3.6 Flash
Gemini 3.6 Flash is the newer release (July 2026, against March 2026 for Grok 4.20 Reasoning).
Monthly cost at three volumes
| Volume | Gemini 3.6 Flash | Grok 4.20 Reasoning | Difference |
|---|---|---|---|
| Prototype: 1M input, 250K output tokens | $1.69 | $1.88 | Gemini 3.6 Flash, $0.19 less |
| Production: 20M input, 5M output tokens | $33.75 | $37.50 | Gemini 3.6 Flash, $3.75 less |
| Scale: 500M input, 100M output tokens | $750.00 | $875.00 | Gemini 3.6 Flash, $125.00 less |
Standard rates, without caching or batch discounts. Volumes are per month.
Specifications side by side
| Gemini 3.6 Flash | Grok 4.20 Reasoning | |
|---|---|---|
| Provider | xAI | |
| Category | Language models | Language models |
| Status | Legacy | Generally available |
| Headline price | $1.50 / 1M tokens | $1.56 / 1M tokens |
| Input | $0.75 / 1M tokens | $1.25 / 1M tokens |
| Output | $3.75 / 1M tokens | $2.50 / 1M tokens |
| Cached input | $0.075 / 1M tokens | $0.20 / 1M tokens |
| Context window | 1.05M | 1M |
| Max output | 66k | No data |
| Released | July 2026 | March 2026 |
| Knowledge cutoff | No data | No data |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API |
| API model id | gemini-3.6-flash | grok-4.20-0309-reasoning |
Benchmarks side by side
Leader in bold.
| Benchmark | Gemini 3.6 Flash | Grok 4.20 Reasoning |
|---|---|---|
| Intelligence Index | 34 | No data |
| SciCode | 53.4% | No data |
| GPQA Diamond | 92.8% | No data |
| Humanity's Last Exam | 40.8% | No data |
| MMMU-Pro (visual reasoning) | 83.2% | No data |
| Long-context reasoning (AA-LCR) | 80% | No data |
Independent evaluations by Artificial Analysis, run the same way for every model, at the reasoning setting shown. Percentages unless marked as an index.
Frequently asked questions
Should I choose Gemini 3.6 Flash or Grok 4.20 Reasoning?
Choose Gemini 3.6 Flash for high-volume, cost-sensitive work, reused prompts and documents (RAG, agents) and the latest release. Choose Grok 4.20 Reasoning for writing and code generation.
Which is cheaper, Gemini 3.6 Flash or Grok 4.20 Reasoning?
Gemini 3.6 Flash is 4% cheaper than Grok 4.20 Reasoning at the headline price ($1.50 / 1M tokens vs $1.56 / 1M tokens).
Which has the larger context window, Gemini 3.6 Flash or Grok 4.20 Reasoning?
Gemini 3.6 Flash reads more per request: 1.05M tokens against 1M.
What is the difference between Gemini 3.6 Flash and Grok 4.20 Reasoning?
Gemini 3.6 Flash is made by Google and Grok 4.20 Reasoning by xAI. Gemini 3.6 Flash is 4% cheaper than Grok 4.20 Reasoning at the headline price ($1.50 / 1M tokens vs $1.56 / 1M tokens). Gemini 3.6 Flash reads more per request: 1.05M tokens against 1M. Gemini 3.6 Flash is the newer model (July 2026, against March 2026).
How much do Gemini 3.6 Flash and Grok 4.20 Reasoning cost per month?
At 20 million input and 5 million output tokens a month, Gemini 3.6 Flash costs $33.75 and Grok 4.20 Reasoning costs $37.50, at standard rates.
Which is newer, Gemini 3.6 Flash or Grok 4.20 Reasoning?
Gemini 3.6 Flash was released on July 2026 and Grok 4.20 Reasoning on March 2026.