DeepSeek V4.1 Flash vs GPT-6 Luna: pricing and benchmarks
GPT-6 Luna is 67% cheaper on input tokens ($0.10 vs $0.30 per 1M). GPT-6 Luna is 58% cheaper on output tokens ($0.50 vs $1.20 per 1M). On our document Q&A workload (50,000 questions a month), GPT-6 Luna costs $55.00 a month versus $156.00 for DeepSeek V4.1 Flash, 65% less. Roughly tied. DeepSeek V4.1 Flash scores 155.6 and GPT-6 Luna scores 156.3 on the Epoch Capabilities Index, and their confidence intervals overlap.
Which should you choose?
Roughly tied. DeepSeek V4.1 Flash scores 155.6 and GPT-6 Luna scores 156.3 on the Epoch Capabilities Index, and their confidence intervals overlap.
GPT-6 Luna scores 78.9% on FrontierMath (Tiers 1–3) vs 67.4% for DeepSeek V4.1 Flash.
GPT-6 Luna costs $0.20 per 1M tokens (3:1 input-to-output mix) vs $0.525 for DeepSeek V4.1 Flash, 62% less.
GPT-6 Luna delivers equal or higher overall capability for 62% less.
Pricing and specs
| DeepSeek V4.1 Flash | GPT-6 Luna | |
|---|---|---|
| Provider | DeepSeek | OpenAI |
| API model ID | deepseek-flash | gpt-6-luna |
| Input / 1M tokens | $0.30 | $0.10 |
| Cached input / 1M tokens | $0.006 | $0.01 |
| Output / 1M tokens | $1.20 | $0.50 |
| Long-context rates | — | $0.20 in / $0.75 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-6 Luna | |
|---|---|---|
| Epoch Capabilities Index | 155.6 | 156.3 |
| GPQA Diamond· Science reasoning | 89.8% | 90.5% |
| FrontierMath (Tiers 1–3)· Advanced math | 67.4% | 78.9% |
| SimpleQA Verified· Factual accuracy | 42.9% | 41.4% |
| ARC-AGI-2· Abstract reasoning | 72.9% | 59.3% |
| DeepSWE· Coding | — | — |
| APEX-Agents· Agentic work | 39.5% | 44.3% |
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-6 Luna | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $93.00 | $35.00 | GPT-6 Luna 62% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $156.00 | $55.00 | GPT-6 Luna 65% 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 | $24.80 | GPT-6 Luna 60% cheaper |
Cached chatbot The same 100,000-reply support chatbot, but 60% of each prompt (system prompt + conversation history) is served from the prompt cache. | $66.54 | $26.90 | GPT-6 Luna 60% cheaper |
Meeting notes 10,000 meetings a month summarized from ~12,000-token transcripts, ~1,000 output tokens each. | $48.00 | $17.00 | GPT-6 Luna 65% cheaper |
Bulk translation 200,000 short translations a month, ~800 input and ~800 output tokens each. | $240.00 | $96.00 | GPT-6 Luna 60% cheaper |
Content moderation 1,000,000 classifications a month, ~400 input tokens and ~80 output tokens each. | $216.00 | $80.00 | GPT-6 Luna 63% cheaper |
Article drafting 300 long-form articles a month written from a ~4,000-token brief and outline, ~5,000 output tokens each. | $2.16 | $0.87 | GPT-6 Luna 60% cheaper |
Code review bot 30,000 pull-request reviews a month, ~5,000 input tokens each (30% cached repository context) and ~700 output tokens. | $56.97 | $21.45 | GPT-6 Luna 62% cheaper |
Invoice extraction 100,000 documents a month parsed into structured JSON, ~1,200 input and ~250 output tokens each. | $66.00 | $24.50 | GPT-6 Luna 63% 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-6 Luna cost calculator
- $55.00/mo$0.0011 / req
- DeepSeek V4.1 FlashDeepSeek$156.00/mo$0.0031 / req
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-6 Luna pricing notes
OpenAI’s most efficient GPT-6 model, for focused, high-volume tasks.
- Cache writes are billed at $0.125 per 1M tokens.
- Fast mode costs 2x the standard rate; Flex costs half.
- Regional (data residency) endpoints add a 10% uplift, and EU data residency is available only with standard processing.
Frequently asked questions
- Is DeepSeek V4.1 Flash cheaper than GPT-6 Luna?
- GPT-6 Luna is 67% cheaper on input tokens ($0.10 vs $0.30 per 1M). GPT-6 Luna is 58% cheaper on output tokens ($0.50 vs $1.20 per 1M). On our document Q&A workload (50,000 questions a month), GPT-6 Luna costs $55.00 a month versus $156.00 for DeepSeek V4.1 Flash, 65% less.
- Which is more capable, DeepSeek V4.1 Flash or GPT-6 Luna?
- Roughly tied. DeepSeek V4.1 Flash scores 155.6 and GPT-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-6 Luna cost per 1M tokens?
- GPT-6 Luna costs $0.10 per 1M input tokens and $0.50 per 1M output tokens, and $0.01 per 1M cached input tokens on OpenAI’s standard tier.
- Which has the larger context window, DeepSeek V4.1 Flash or GPT-6 Luna?
- GPT-6 Luna has the larger context window: 1.05M tokens versus 1M for DeepSeek V4.1 Flash.