High-volume, cost-sensitive work
Choose Grok 4.20 Reasoning
Grok 4.20 Reasoning costs 19% less on a typical mix of three input tokens for every output token ($1.56 against $1.93 per million tokens).
Grok 4.20 Reasoning vs o3-mini: price, context and capabilities
Choose Grok 4.20 Reasoning for high-volume, cost-sensitive work, writing and code generation, reused prompts and documents (RAG, agents), very long inputs and the latest release; on the other points the two are level or the data is missing.
In short
- Grok 4.20 Reasoning is 19% cheaper than o3-mini at the headline price ($1.56 / 1M tokens vs $1.93 / 1M tokens).
- Grok 4.20 Reasoning reads more per request: 1M tokens against 200k.
- Grok 4.20 Reasoning is the newer model (March 2026, against Jan 31, 2025).
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 $4.40 for o3-mini. Output dominates the bill when answers are long.
Reused prompts and documents (RAG, agents)
Choose Grok 4.20 Reasoning
Grok 4.20 Reasoning charges $0.20 per million cached input tokens, against $0.55 for o3-mini.
Very long inputs
Choose Grok 4.20 Reasoning
Grok 4.20 Reasoning reads up to 1M tokens per request, against 200k for o3-mini.
Latest release
Choose Grok 4.20 Reasoning
Grok 4.20 Reasoning is the newer release (March 2026, against Jan 31, 2025 for o3-mini).
Monthly cost at three volumes
| Volume | Grok 4.20 Reasoning | o3-mini | Difference |
|---|---|---|---|
| Prototype: 1M input, 250K output tokens | $1.88 | $2.20 | Grok 4.20 Reasoning, $0.33 less |
| Production: 20M input, 5M output tokens | $37.50 | $44.00 | Grok 4.20 Reasoning, $6.50 less |
| Scale: 500M input, 100M output tokens | $875.00 | $990.00 | Grok 4.20 Reasoning, $115.00 less |
Standard rates, without caching or batch discounts. Volumes are per month.
Specifications side by side
| Grok 4.20 Reasoning | o3-mini | |
|---|---|---|
| Provider | xAI | OpenAI |
| Category | Language models | Language models |
| Status | Generally available | Deprecated |
| Headline price | $1.56 / 1M tokens | $1.93 / 1M tokens |
| Input | $1.25 / 1M tokens | $1.10 / 1M tokens |
| Output | $2.50 / 1M tokens | $4.40 / 1M tokens |
| Cached input | $0.20 / 1M tokens | $0.55 / 1M tokens |
| Context window | 1M | 200k |
| Max output | No data | 100k |
| Released | March 2026 | Jan 31, 2025 |
| Knowledge cutoff | No data | October 2023 |
| 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 | grok-4.20-0309-reasoning | o3-mini |
Benchmarks side by side
Leader in bold.
| Benchmark | Grok 4.20 Reasoning | o3-mini |
|---|---|---|
| Terminal-Bench Hard | No data | 6.8% |
| GPQA Diamond | No data | 74.8% |
| Humanity's Last Exam | No data | 7.9% |
| τ²-Bench (agentic tool use) | No data | 28.7% |
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 Grok 4.20 Reasoning or o3-mini?
Choose Grok 4.20 Reasoning for high-volume, cost-sensitive work, writing and code generation, reused prompts and documents (RAG, agents), very long inputs and the latest release; on the other points the two are level or the data is missing.
Which is cheaper, Grok 4.20 Reasoning or o3-mini?
Grok 4.20 Reasoning is 19% cheaper than o3-mini at the headline price ($1.56 / 1M tokens vs $1.93 / 1M tokens).
Which has the larger context window, Grok 4.20 Reasoning or o3-mini?
Grok 4.20 Reasoning reads more per request: 1M tokens against 200k.
What is the difference between Grok 4.20 Reasoning and o3-mini?
Grok 4.20 Reasoning is made by xAI and o3-mini by OpenAI. Grok 4.20 Reasoning is 19% cheaper than o3-mini at the headline price ($1.56 / 1M tokens vs $1.93 / 1M tokens). Grok 4.20 Reasoning reads more per request: 1M tokens against 200k. Grok 4.20 Reasoning is the newer model (March 2026, against Jan 31, 2025).
How much do Grok 4.20 Reasoning and o3-mini cost per month?
At 20 million input and 5 million output tokens a month, Grok 4.20 Reasoning costs $37.50 and o3-mini costs $44.00, at standard rates.
Which is newer, Grok 4.20 Reasoning or o3-mini?
Grok 4.20 Reasoning was released on March 2026 and o3-mini on Jan 31, 2025.