DeepSeek V4 Pro vs GPT-5.6 Sol
Both are Flagship-tier models, from DeepSeek and OpenAI respectively. DeepSeek V4 Pro is the cheaper choice overall at a 4:1 input:output ratio.
Which is cheaper
- Input price: DeepSeek V4 Pro is cheaper ($1.32 vs $4.00).
- Output price: DeepSeek V4 Pro is cheaper ($3.96 vs $20.00).
- Blended, 4:1 input:output ratio: DeepSeek V4 Pro is 74.3% cheaper ($1.85 vs $7.20 per weighted 1M tokens).
Side by side
| Spec | DeepSeek V4 Pro | GPT-5.6 Sol |
|---|---|---|
| Provider | DeepSeek | OpenAI |
| Tier | Flagship | Flagship |
| Context window | 1M | 1.05M |
| Max output | 384K | 128K |
| Input $/1M | $1.32 | $4.00 |
| Output $/1M | $3.96 | $20.00 |
| Cache read $/1M | $0.044 | $0.40 |
| Cache write $/1M | — | $5.00 |
| Modalities | text | text, image |
DeepSeek V4 Pro. Peak cache-miss rate, which is this dataset's standard tier. DeepSeek's own page states off-peak rates are half the peak rates, with peak hours 01:00-04:00 and 06:00-10:00 UTC Monday to Friday: off-peak is $0.66 input / $1.98 output, cache-hit input $0.022. The off-peak half-price is a time-of-day discount and is excluded here for the same reason batch and cached-input discounts are.
GPT-5.6 Sol. Short-context rate, for prompts up to 272K input tokens. Above 272K the rate is $8 input / $30 output, cache read $0.80, cache write $10 per 1M. Promotional pricing, stated to run at least through 21 November 2026.
Sources
DeepSeek V4 Pro — verified August 30, 2026
GPT-5.6 Sol — verified August 29, 2026
Full DeepSeek V4 Pro pricing page → · Full GPT-5.6 Sol pricing page →