DeepSeek V4 Pro vs GPT-6 Sol cost.
OpenAI halved the price of this tier in September. The gap to DeepSeek narrowed sharply, and it is still large.
- Input gap
- 3×
- Output gap
- 5.1×
- Cached gap
- 9.1×
- Rates verified
- 2026-10-02
Current-model note: Both models are current. GPT-6 Sol replaced GPT-5.6 Sol at half the price on 22 September 2026, and this page replaces the GPT-5.6 Sol comparison. DeepSeek rates shown are off-peak, from DeepSeek's official pricing page.
| Current model | Input / 1M | Cached / 1M | Cache write / 1M | Output / 1M | Context |
|---|---|---|---|---|---|
| DeepSeek V4 ProOfficial pricing ↗ | $0.66 | $0.022 | — | $1.98 | 1,000,000 |
| GPT-6 SolOfficial pricing ↗ | $2.00 | $0.20 | $2.50 | $10.00 | 1,050,000 |
Rates verified 2026-10-02. The browser may refresh them from the live catalogue. Provider pricing and tiers remain authoritative.
Rates shown are DeepSeek's off-peak prices. From 01:00 to 04:00 and 06:00 to 10:00 UTC, Monday to Friday (except Chinese public holidays), DeepSeek charges double.
DeepSeek V4 Pro: the public catalogue lists an outdated rate, so this rate comes from the official pricing page.
DeepSeek V4 Pro: Provider-Calibrated UTF-8 Projection
GPT-6 Sol: exact local BPE tokenization
PDF, DOCX, code, text, and data files are extracted locally and applied to both models.
DeepSeek V4 Pro: unavailable
GPT-6 Sol: documented formula
Prompt text, document contents, and image pixels stay in the browser.
Text, code, PDF, DOCX, images, audio, or video · 12 MB per file
Your input, measured across providers.
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Workload & Scaling Planner +
What five real workloads actually cost
Headline per-token prices rarely decide a bill. Request shape does. These figures are calculated from the verified rates for DeepSeek V4 Pro and GPT-6 Sol, including any long-context tier that applies once a request crosses its threshold.
| Workload | Input | Output | DeepSeek V4 Pro | GPT-6 Sol | Difference |
|---|---|---|---|---|---|
| Short chat turn A typical assistant exchange. | 1,000 | 500 | $0.0016 | $0.0070 | 4.24x cheaper on DeepSeek V4 Pro |
| RAG answer Five retrieved chunks plus a question. | 12,000 | 800 | $0.0095 | $0.032 | 3.37x cheaper on DeepSeek V4 Pro |
| Code review A medium pull request with surrounding files. | 60,000 | 2,000 | $0.044 | $0.140 | 3.21x cheaper on DeepSeek V4 Pro |
| Whole-document analysis A long report or contract read in one call. | 300,000 | 4,000 | $0.206 | $1.26 (tier) | 6.12x cheaper on DeepSeek V4 Pro |
| Full-context load Filling most of a one-million-token window. | 900,000 | 4,000 | $0.602 | $3.66 (tier) | 6.08x cheaper on DeepSeek V4 Pro |
"(tier)" marks a request that crossed a long-context threshold, so it is billed above the headline rate. Output length is the assumption most worth changing for your own case: paste a real prompt into the calculator above to replace these with your numbers.
The cached-input rate is the number most comparisons miss
Agents, chat threads and RAG pipelines resend the same system prompt and context on every call. Those repeated tokens bill at the cached rate, not the headline rate, so a model can be cheaper on paper and more expensive in production. Here the gap is 9.1x: DeepSeek V4 Pro reads cached tokens at $0.022 per million.
| Model | Fresh input / 1M | Cached input / 1M | Discount | Break-even |
|---|---|---|---|---|
| DeepSeek V4 Pro | $0.660 | $0.022 | 97% | 1 read |
| GPT-6 Sol | $2.00 | $0.200 | 90% | 1 read |
Break-even assumes a cache write costs about 1.25x the base input rate, which is what OpenAI and Anthropic currently document for a short time-to-live. It answers one question: how many times a cached prefix must be re-read before caching is cheaper than paying full price each call. Above that count, every further read saves the discount shown.
The gap narrowed from ten times to five
Off-peak, DeepSeek V4 Pro lists $0.66 per million input tokens and $1.98 output. GPT-6 Sol lists $2 and $10. That is about three times on input and five times on output.
Against the model GPT-6 Sol replaced, GPT-5.6 Sol at $4 and $20, the gap was six times and ten times. A single OpenAI release halved it. During DeepSeek's peak hours, when V4 Pro costs $1.32 and $3.96, the gap narrows further to about one and a half times on input and two and a half on output.
This is the pattern worth watching: frontier prices are falling fast enough that a cost advantage measured six months ago may no longer hold.
Open-weight models have closed much of the quality gap
The open-weight tier is no longer only a budget option. Published comparisons in 2026 put Kimi K3, Qwen3.8-Max and GLM-5.2 above 91 percent on GPQA Diamond, a graduate-level science reasoning benchmark that closed frontier models led not long ago.
Benchmarks still do not settle your task. They narrow the shortlist; a held-out evaluation on your own data decides it.
DeepSeek also publishes V4.1 Flash, which beats V4 Pro on its own coding benchmarks at a quarter of the price. If the workload is code, <a href="/deepseek-v4-1-flash-vs-deepseek-v4-pro-cost/">compare those two first</a>.
Counting confidence differs
GPT-6 Sol is tokenized exactly in your browser. DeepSeek V4 Pro is measured with a deterministic byte-length projection and labelled as an estimate.
When the price gap is several-fold, projection error is not what decides the comparison. But if you are reconciling an invoice rather than planning a budget, use the provider's own usage figures.
Model the workload, not the marketing price.
The gap is smaller than it was but still large enough that quality on your task decides, not price. Measure output quality first, then use the calculator to size the saving.
Review calculation methodology →Measure against the model you use
Other comparisons worth running
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Frequently asked questions
How much cheaper is DeepSeek V4 Pro than GPT-6 Sol?+
About three times cheaper on input ($0.66 against $2 per million tokens) and five times cheaper on output ($1.98 against $10) at off-peak rates. During DeepSeek peak hours the gap halves.
What happened to the GPT-5.6 Sol comparison?+
GPT-6 Sol replaced it on 22 September 2026 at half the price, $2 and $10 per million instead of $4 and $20. This page replaces the earlier comparison and its address redirects here.
Is an open-weight model good enough to replace a frontier model?+
It depends entirely on the task. Published 2026 comparisons put several open-weight models above 91 percent on GPQA Diamond, close to frontier performance on reasoning benchmarks. Run a held-out evaluation on your own data before switching.
Does DeepSeek pricing change by time of day?+
Yes. DeepSeek charges double from 01:00 to 04:00 and 06:00 to 10:00 UTC, Monday to Friday, except Chinese public holidays. This page shows the off-peak rate.