Grok 4.1 Fast vs DeepSeek V3
Side-by-side comparison of Grok 4.1 Fast (xAI) and DeepSeek V3 (DeepSeek). Exact API pricing per million tokens, context windows, output speed, and total cost on real-world prompts.
Specifications
| Spec | Grok 4.1 Fast | DeepSeek V3 |
|---|---|---|
| Provider | xAI | DeepSeek |
| Model id | grok-4.1-fast | deepseek-v3 |
| Input price (per 1M tokens) | $0.20 | $0.28 |
| Output price (per 1M tokens) | $0.50 | $0.42 |
| Context window | 2,000,000 | 128,000 |
| Output speed (tokens/sec) | ~180 | ~60 |
Cost on real prompts
Total cost = (input tokens × input price) + (output tokens × output price). Numbers below use the exact pricing tables published by each provider.
| Scenario | Input | Output | Grok 4.1 Fast | DeepSeek V3 | Cheaper |
|---|---|---|---|---|---|
| Short question + answer | 50 | 150 | $0.000085 | $0.000077 | DeepSeek V3 |
| Code review on one file | 500 | 1,500 | $0.00085 | $0.00077 | DeepSeek V3 |
| Long document summary | 5,000 | 500 | $0.001250 | $0.001610 | Grok 4.1 Fast |
| Heavy reasoning task | 2,000 | 8,000 | $0.004400 | $0.003920 | DeepSeek V3 |
| Full codebase analysis | 50,000 | 10,000 | $0.015000 | $0.018200 | Grok 4.1 Fast |
Want the exact cost for your prompt instead of these examples? Open the cost calculator pre-loaded with both models →
When to pick which
Heuristics derived from the spec table above. Always validate on your own prompts before committing — these are starting points, not verdicts.
Pick Grok 4.1 Fast for
- •input-heavy workloads (long context, RAG, document QA) — grok-4.1-fast is cheaper per input token
- •tasks needing a larger context window — grok-4.1-fast fits 16x more tokens than deepseek-v3
- •latency-sensitive UX (chat, autocompletion) — grok-4.1-fast streams faster (~180 vs ~60 tok/s)
Pick DeepSeek V3 for
No clear advantage on the data points we measure. Compare on your actual prompts.
Switching between them
For most use cases, switching providers means updating the model id and the request shape if the providers differ. Within the same provider, it's usually a single-line change.
From Grok 4.1 Fast to DeepSeek V3
# Before
model = "grok-4.1-fast"
# After
model = "deepseek-v3"If the providers differ (xAI vs DeepSeek), you'll also need to swap the SDK / endpoint URL. Cross-provider migrations usually take 30 minutes to a few hours depending on how many features (streaming, function calling, tool use) you depend on.
Calculate cost on your own prompt
The examples above use generic input/output ratios. For an exact comparison, paste your real prompt into the calculator — it counts tokens with the right tokenizer for each model and shows side-by-side cost.
Open the calculator with both models →