Grok 4 Fast Non Reasoning vs Grok 4 Fast Reasoning
Grok 4 Fast Reasoning comes out ahead, 75 to 72 on our weighted score.
xAIGrok 4 Fast Non Reasoning
72/100- ECI—
- Price$0.20 / $0.50
- Context2M
- Our pickxAI
Grok 4 Fast Reasoning
75/100- ECI—
- Price$0.20 / $0.50
- Context2M
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Make it a three-way comparison.
Grok 4 Fast Reasoning is our pick
Grok 4 Fast Reasoning is the better all-round choice, scoring 75/100 against Grok 4 Fast Non Reasoning (72). It leads 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 priceSame priceGrok 4 Fast Non Reasoning $0.275 · Grok 4 Fast Reasoning $0.275 per 1M tokens (3:1 blend)
- Longest contextAbout the sameGrok 4 Fast Non Reasoning 2,000,000 · Grok 4 Fast Reasoning 2,000,000 tokens
- Widest inputsSame inputsGrok 4 Fast Non Reasoning: Text, Images, Audio, Video · Grok 4 Fast Reasoning: Text, Images, Audio, Video
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Grok 4 Fast Non Reasoning | Grok 4 Fast Reasoning |
|---|---|---|---|
| Price | 50% | 73 | 73 |
| Inputs & features | 30% | 70 | 80 |
| Context window | 20% | 72 | 72 |
| Overall | 100% | 72/100 | 75/100 |
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 Fast Non ReasoningxAI | Grok 4 Fast ReasoningxAI |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $0.20 | $0.20 |
| Output | $0.50 | $0.50 |
| Cached input | — | — |
| Blended (3:1) | $0.275 | $0.275 |
| Long-context rate | Same rate | Same rate |
| Price source | Median of 7 providers | Median of 4 providers |
| Limits | ||
| Context window | 2,000,000 tokens | 2,000,000 tokens |
| Max output | 2,000,000 tokens | 2,000,000 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | No | No |
| Audio | Yes | Yes |
| Video | Yes | Yes |
| Reasoning | No | Yes |
| Tool calling | Yes | Yes |
| Structured output | No | No |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | — | — |
| API providers | 8 (best) | 5 |
| Released | Dec 18, 2025 | Dec 18, 2025 |
| Knowledge cutoff | — | — |
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 Fast Non Reasoning$3.00
- Grok 4 Fast Reasoning$3.00
Which should you choose?
Which is better: Grok 4 Fast Non Reasoning or Grok 4 Fast Reasoning?
Grok 4 Fast Reasoning is the better all-round choice, scoring 75/100 against Grok 4 Fast Non Reasoning (72). It leads 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 Fast Non Reasoning or Grok 4 Fast Reasoning?
Grok 4 Fast Non Reasoning and Grok 4 Fast Reasoning cost the same: $0.20 input / $0.50 output per million tokens.
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Grok 4 Fast Non Reasoning has not been scored yet and Grok 4 Fast Reasoning has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Grok 4 Fast Non Reasoning and Grok 4 Fast Reasoning 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 Fast Non Reasoning and Grok 4 Fast Reasoning share the same 2,000,000-token context window. Maximum output per response: Grok 4 Fast Non Reasoning up to 2,000,000, Grok 4 Fast Reasoning up to 2,000,000 tokens.
Which can read images, PDFs, audio or video?
Grok 4 Fast Non Reasoning accepts text, images, audio and video; Grok 4 Fast Reasoning accepts text, images, audio and video. They handle the same number of input types.
Are any of these open source?
No. Grok 4 Fast Non Reasoning and Grok 4 Fast Reasoning are proprietary and only available through APIs and apps.
Which is newer?
Grok 4 Fast Non Reasoning is the newest, released Dec 18, 2025. Grok 4 Fast Reasoning came out Dec 18, 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 Nov 2, 2026.
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