Grok 4.1 Fast vs Gemini Robotics-ER 1.6 Preview
Grok 4.1 Fast comes out ahead, 71 to 50 on our weighted score, and it is the cheaper option too.
- Our pick
xAIGrok 4.1 Fast
71/100- ECI—
- Price$0.20 / $0.50
- Context2M
GoogleGemini Robotics-ER 1.6 Preview
50/100- ECI—
- Price$1.00 / $5.00
- Context131K
Add a model
Make it a three-way comparison.
Grok 4.1 Fast is our pick
Grok 4.1 Fast is the better all-round choice, scoring 71/100 against Gemini Robotics-ER 1.6 Preview (50). It leads on price and context window. Gemini Robotics-ER 1.6 Preview wins on inputs & features. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceGrok 4.1 FastGrok 4.1 Fast $0.275 · Gemini Robotics-ER 1.6 Preview $2.00 per 1M tokens (3:1 blend)
- Longest contextGrok 4.1 FastGrok 4.1 Fast 2,000,000 · Gemini Robotics-ER 1.6 Preview 131,072 tokens
- Widest inputsGemini Robotics-ER 1.6 PreviewGrok 4.1 Fast: Text, Images · Gemini Robotics-ER 1.6 Preview: Text, Images, Audio, Video
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Grok 4.1 Fast | Gemini Robotics-ER 1.6 Preview |
|---|---|---|---|
| Price | 50% | 76 | 36 |
| Inputs & features | 30% | 60 | 90 |
| Context window | 20% | 72 | 24 |
| Overall | 100% | 71/100 | 50/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Grok 4.1 FastxAI | Gemini Robotics-ER 1.6 PreviewGoogle |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $0.20 (best) | $1.00 |
| Output | $0.50 (best) | $5.00 |
| Cached input | — | — |
| Blended (3:1) | $0.275 (best) | $2.00 |
| Long-context rate | Same rate | Same rate |
| Price source | Median of 2 providers | Median of 1 providers |
| Limits | ||
| Context window | 2,000,000 tokens (best) | 131,072 tokens |
| Max output | 30,000 tokens | 65,536 tokens (best) |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | No | No |
| Audio | No | Yes |
| Video | No | Yes |
| Reasoning | No | Yes |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | — | — |
| API providers | 2 (best) | 1 |
| Released | Nov 19, 2025 | Apr 14, 2026 |
| Knowledge cutoff | — | Jan 2025 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Grok 4.1 Fast$3.00
- Gemini Robotics-ER 1.6 Preview$20.00
Which should you choose?
Which is better: Grok 4.1 Fast or Gemini Robotics-ER 1.6 Preview?
Grok 4.1 Fast is the better all-round choice, scoring 71/100 against Gemini Robotics-ER 1.6 Preview (50). It leads on price and context window. Gemini Robotics-ER 1.6 Preview wins on inputs & features. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, Grok 4.1 Fast or Gemini Robotics-ER 1.6 Preview?
Grok 4.1 Fast is cheaper at $0.20 input / $0.50 output per million tokens (median across 2 API providers). Gemini Robotics-ER 1.6 Preview costs $1.00 input / $5.00 output per million tokens (median across 1 API provider). At a typical mix of three input tokens to one output token, that is $0.275 per million tokens for Grok 4.1 Fast versus $2.00 for Gemini Robotics-ER 1.6 Preview (7.3× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Grok 4.1 Fast has not been scored yet and Gemini Robotics-ER 1.6 Preview has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Grok 4.1 Fast and Gemini Robotics-ER 1.6 Preview yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.
Which has the bigger context window?
Grok 4.1 Fast has the largest context window at 2,000,000 tokens, against 131,072 for Gemini Robotics-ER 1.6 Preview. Maximum output per response: Grok 4.1 Fast up to 30,000, Gemini Robotics-ER 1.6 Preview up to 65,536 tokens.
Which can read images, PDFs, audio or video?
Grok 4.1 Fast accepts text and images; Gemini Robotics-ER 1.6 Preview accepts text, images, audio and video. Gemini Robotics-ER 1.6 Preview handles the widest range of inputs.
Are any of these open source?
No. Grok 4.1 Fast and Gemini Robotics-ER 1.6 Preview are proprietary and only available through APIs and apps.
Which is newer?
Gemini Robotics-ER 1.6 Preview is the newest, released Apr 14, 2026. Grok 4.1 Fast came out Nov 19, 2025. Knowledge cutoff: Gemini Robotics-ER 1.6 Preview Jan 2025.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
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