DeepSeek V4.1 Flash vs GPT-5.6 Luna: pricing and benchmarks
GPT-5.6 Luna is 33% cheaper on input tokens ($0.20 vs $0.30 per 1M). Both charge $1.20 per 1M output tokens. On our document Q&A workload (50,000 questions a month), GPT-5.6 Luna costs $116.00 a month versus $156.00 for DeepSeek V4.1 Flash, 26% less. Roughly tied. DeepSeek V4.1 Flash scores 155.6 and GPT-5.6 Luna scores 156.3 on the Epoch Capabilities Index, and their confidence intervals overlap.
Prices verified October 29, 2026.
Which should you choose?
Roughly tied. DeepSeek V4.1 Flash scores 155.6 and GPT-5.6 Luna scores 156.3 on the Epoch Capabilities Index, and their confidence intervals overlap.
GPT-5.6 Luna scores 82.1% on FrontierMath (Tiers 1–3) vs 67.4% for DeepSeek V4.1 Flash.
GPT-5.6 Luna costs $0.45 per 1M tokens (3:1 input-to-output mix) vs $0.525 for DeepSeek V4.1 Flash, 14% less.
GPT-5.6 Luna delivers equal or higher overall capability for 14% less.
Pricing and specs
| DeepSeek V4.1 Flash | GPT-5.6 Luna | |
|---|---|---|
| Provider | DeepSeek | OpenAI |
| API model ID | deepseek-flash | gpt-5.6-luna |
| Input / 1M tokens | $0.30 | $0.20 |
| Cached input / 1M tokens | $0.006 | $0.02 |
| Output / 1M tokens | $1.20 | $1.20 |
| Long-context rates | — | $0.40 in / $1.80 out on long-context requests |
| Context window | 1M tokens | 1.05M tokens |
| Max output | 384K tokens | 128K tokens |
| Batch discount | — | 50% off |
Benchmarks
| DeepSeek V4.1 Flash | GPT-5.6 Luna | |
|---|---|---|
| Epoch Capabilities Index | 155.6 | 156.3 |
| GPQA Diamond· Science reasoning | 89.8% | 91.6% |
| FrontierMath (Tiers 1–3)· Advanced math | 67.4% | 82.1% |
| SimpleQA Verified· Factual accuracy | 42.9% | 41.0% |
| ARC-AGI-2· Abstract reasoning | 72.9% | 59.5% |
| DeepSWE· Coding | — | 67.2% |
| APEX-Agents· Agentic work | 39.5% | 43.0% |
Source: Epoch AI, best recorded result per model (CC BY 4.0). A dash means no published score. See all benchmarks
Monthly cost for real workloads
| Workload | DeepSeek V4.1 Flash | GPT-5.6 Luna | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $93.00 | $78.00 | GPT-5.6 Luna 16% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $156.00 | $116.00 | GPT-5.6 Luna 26% cheaper |
Coding agent 10,000 agent steps a month, ~40,000 input tokens each (70% read from the prompt cache) and ~2,000 output tokens. | $61.68 | $53.60 | GPT-5.6 Luna 13% cheaper |
Estimates use standard list prices and ignore cache-write surcharges. Different tokenizers can count the same text differently, so test with your own prompts.
DeepSeek V4.1 Flash vs GPT-5.6 Luna cost calculator
- $116.00/mo$0.0023 / request
- DeepSeek V4.1 FlashDeepSeek$156.00/mo$0.0031 / request
Standard-tier list prices. Long-context rates apply automatically where the provider publishes a threshold. Excludes cache-write surcharges, taxes, batch and volume discounts.
DeepSeek V4.1 Flash pricing notes
DeepSeek’s low-cost model with thinking and non-thinking modes, tool calls and vision input.
- Prices shown are peak rates. Off-peak rates are half: peak hours are 01:00–04:00 and 06:00–10:00 UTC, Monday to Friday.
- Compatible with both OpenAI-format and Anthropic-format APIs.
- Served by model version DeepSeek-V4.1-Flash-1017; the legacy names deepseek-v4-flash and deepseek-v4-flash-vision-exp route to it at the same price.
- Web Search and Fetch cost $0.75 per 1,000 successful requests each; calls made through Claude Code, Codex or DeepSeek Harness are free until November 1, 2026.
GPT-5.6 Luna pricing notes
The GPT-5.6 model optimized for cost-sensitive, high-volume workloads.
- Cache writes are billed at $0.25 per 1M tokens.
- Fast mode costs 2x the standard rate; Flex costs half.
Frequently asked questions
- Is DeepSeek V4.1 Flash cheaper than GPT-5.6 Luna?
- GPT-5.6 Luna is 33% cheaper on input tokens ($0.20 vs $0.30 per 1M). Both charge $1.20 per 1M output tokens. On our document Q&A workload (50,000 questions a month), GPT-5.6 Luna costs $116.00 a month versus $156.00 for DeepSeek V4.1 Flash, 26% less.
- Which is more capable, DeepSeek V4.1 Flash or GPT-5.6 Luna?
- Roughly tied. DeepSeek V4.1 Flash scores 155.6 and GPT-5.6 Luna scores 156.3 on the Epoch Capabilities Index, and their confidence intervals overlap.
- How much does DeepSeek V4.1 Flash cost per 1M tokens?
- DeepSeek V4.1 Flash costs $0.30 per 1M input tokens and $1.20 per 1M output tokens, and $0.006 per 1M cached input tokens on DeepSeek’s standard tier.
- How much does GPT-5.6 Luna cost per 1M tokens?
- GPT-5.6 Luna costs $0.20 per 1M input tokens and $1.20 per 1M output tokens, and $0.02 per 1M cached input tokens on OpenAI’s standard tier.
- Which has the larger context window, DeepSeek V4.1 Flash or GPT-5.6 Luna?
- GPT-5.6 Luna has the larger context window: 1.05M tokens versus 1M for DeepSeek V4.1 Flash.