DeepSeek Cost Comparison: Flash vs Pro | Generated by AI
Question: Is DeepSeek V4 Flash ~4x cheaper than DeepSeek V4 Pro on OpenRouter?
Answer:
Not exactly 4x — it’s actually ~3.1x cheaper, which is close but not quite 4x. Here’s the exact breakdown:
| Model | Input ($/M tokens) | Output ($/M tokens) | Activated Params |
|---|---|---|---|
| DeepSeek V4 Pro | $0.435 | $0.870 | 49B |
| DeepSeek V4 Flash | $0.140 | $0.280 | 13B |
| Ratio | 3.1x | 3.1x | 3.8x |
So the ratio is consistent at 3.1x on both input and output. You were roughly right — “~4x” is a reasonable mental model, but the precise number is ~3x.
What you’re trading:
- Flash: 284B total / 13B activated — fast, cheap, good for coding assistants and agent loops
- Pro: 1.6T total / 49B activated — heavier reasoning, better on hard math/code, 1M context with hybrid attention
For your use case — daily AI assistant, CLI agents, code iteration — Flash is a solid default. Reserve Pro for tasks where you actually need that extra reasoning headroom (complex multi-file refactors, hard algo problems, long-context analysis). You could likely cut your $8/day bill to ~$2.50/day just by routing 80% of traffic to Flash.
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