Pricing comparison
GPT-5.6 Luna vs DeepSeek V4 Flash
Per-token pricing, full-workload cost ladders, and monthly volume projections. Numbers sourced directly from each provider's rate card.
OpenAI
GPT-5.6 Luna
- Input
- $1.00 / 1M
- Output
- $6.00 / 1M
- Cached input
- $0.100 / 1M
- Context
- 1.5M
- Max output
- 128K
DeepSeek
DeepSeek V4 Flash
- Input
- $0.14 / 1M
- Output
- $0.28 / 1M
- Cached input
- $0.003 / 1M
- Context
- 1M
- Max output
- 384K
Cost per request
Four common workload shapes, input tokens and a 1:2 output ratio (a standard chat/completion pattern). Long-context surcharges apply automatically where the provider charges them.
| Scenario | Tokens (in / out) | GPT-5.6 Luna | DeepSeek V4 Flash | Winner |
|---|---|---|---|---|
| Short prompt | 100 / 200 | $0.0013 | $0.0001 | DeepSeek V4 Flash |
| Typical request | 1,000 / 2,000 | $0.0130 | $0.0007 | DeepSeek V4 Flash |
| Long document | 10,000 / 5,000 | $0.0400 | $0.0028 | DeepSeek V4 Flash |
| Large prompt | 100,000 / 10,000 | $0.1600 | $0.0168 | DeepSeek V4 Flash |
Monthly bill at scale
Projected monthly cost at typical request volume, assuming the "typical request" shape above (1k in, 2k out).
| Traffic | Req / month | GPT-5.6 Luna | DeepSeek V4 Flash | Delta |
|---|---|---|---|---|
| Small SaaS | 1,000 | $13.00 | $0.70 | DeepSeek V4 Flash -$12.30 |
| Growing product | 10,000 | $130.00 | $7.00 | DeepSeek V4 Flash -$123.00 |
| Heavy usage | 100,000 | $1,300 | $70.00 | DeepSeek V4 Flash -$1,230 |
Which should you use?
For the typical chat-shape request (~1k input, 2k output), DeepSeek V4 Flash comes out 1757% cheaper. If you're picking one as the default, that's usually the right choice on cost alone.
DeepSeek V4 Flash wins on both sides of the bill - cheaper input and cheaper output. If the quality gap is in your favour, there's no cost argument for the other side.
Context window differs: GPT-5.6 Luna holds 1.5M of input vs 1M on the other side. If you regularly push past the smaller ceiling, the comparison ends there.
Live cost calculator
Type in any token counts - both prices update instantly. Uses base input/output rates (no cache discount, no long-context tier).
GPT-5.6 Luna
$0.0040
per request
DeepSeek V4 Flash
$0.0003
per request
Try both in the estimator →
Drop your actual prompt in, tokens are counted with the provider's own tokenizer, and the dollar number matches what lands on your invoice.
Frequently asked
- Which is cheaper, GPT-5.6 Luna or DeepSeek V4 Flash?
- On a typical 1,000-input / 2,000-output request, DeepSeek V4 Flash costs ~$0.0007 vs ~$0.0130 on GPT-5.6 Luna. Input or output rates can flip the answer for very lopsided workloads - see the cost ladder above.
- What's the difference in per-token pricing?
- GPT-5.6 Luna charges $1.00 per 1M input tokens and $6.00 per 1M output tokens. DeepSeek V4 Flash charges $0.14 / $0.28 per 1M.
- Which has the bigger context window?
- GPT-5.6 Luna is larger (1.5M) vs 1M on the other.
- Is there a cached-input discount on either?
- GPT-5.6 Luna caches at $0.100 per 1M (90% off). DeepSeek V4 Flash caches at $0.003 per 1M (98% off). Workloads with repeated static prefixes see the biggest savings.
- How fresh is this comparison?
- GPT-5.6 Luna was re-verified on 2026-07-01 and DeepSeek V4 Flash on 2026-07-01 against each provider's published rate card. Calcis re-checks every row on a rolling schedule and re-deploys when a provider changes pricing.
GPT-5.6 Luna verified 2026-07-01 · DeepSeek V4 Flash verified 2026-07-01. Rate cards at OpenAI and DeepSeek.