Cost and performance comparison
GPT-5.6 Luna vs DeepSeek V3
Model AOpenAI
GPT-5.6 Luna
- Cost / 1M Tokens
- $0.50
- 70% in · 30% out mix
- Value Index (score÷cost)
- 170.0
- Higher = better value
- Speed
- 98/100
- Context
- 1.1M
- Tier
- Fast Tier
List price from the OpenAI pricing page, verified October 12, 2026.
Check the sourceModel BDeepSeek
DeepSeek V3
- Cost / 1M Tokens
- $0.52
- 70% in · 30% out mix
- Value Index (score÷cost)
- 158.7
- Higher = better value
- Speed
- 85/100
- Context
- 128K
- Tier
- Fast Tier
Last list price before the model was retired.
Across the 25 languages we measured, it needs about 21% more tokens than OpenAI's for the same text. Costs by language
In-depth analysis
GPT-5.6 Luna vs DeepSeek V3: Detailed Comparison
GPT-5.6 Luna is OpenAI's lightweight-tier language model with a 1.1M-token context window, excelling at data extraction. DeepSeek V3 from DeepSeek is a lightweight-tier model supporting 128K tokens in context, with standout performance in data extraction.
Price is not the deciding factor here. For the same text, GPT-5.6 Luna and DeepSeek V3 land within 6% of each other, which is inside the margin your own input/output ratio will move anyway. Pick on capability, context, or latency instead — the monthly bill will look much the same either way. GPT-5.6 Luna is priced at $0.20/M input tokens and $1.20/M output tokens. DeepSeek V3 costs $0.27/M input and $1.10/M output.
On iOPTERA's editorial scores, GPT-5.6 Luna leads with 84/100 for coding and 85/100 for reasoning, against DeepSeek V3's 84/100 and 84/100.
Capability breakdown
Across the five core benchmark categories, here is how GPT-5.6 Luna and DeepSeek V3 stack up head to head:
Best model by task
- reasoning: GPT-5.6 Luna wins with 85/100
- data extraction: GPT-5.6 Luna wins with 92/100
- creative tasks: GPT-5.6 Luna wins with 84/100
- vision/multimodal: GPT-5.6 Luna wins with 85/100
Estimated monthly cost at scale
For 10M + 2M tokens of text a month (counted the way OpenAI's tokenizer counts), GPT-5.6 Luna runs about $4.40 while DeepSeek V3 runs about $5.00 — GPT-5.6 Luna saves roughly $0.60 (12%) every month.
What actually decides it
GPT-5.6 Luna and DeepSeek V3 come from different labs, which means different tokenizers, different API shapes, and a second vendor relationship. The same English text does not produce the same token count on both, so a price-per-million comparison understates the difference — measure your own prompts on each before treating the headline rates as the full story.
GPT-5.6 Luna and DeepSeek V3 are 19 months apart, which is more than one generation in this market. Benchmark comparisons across that gap flatter the older model: it was measured against the evaluations that existed at the time. Treat DeepSeek V3's scores as a floor for what it does well and be sceptical of a close-looking result.
The context gap is the largest single difference on this pair: GPT-5.6 Luna takes 1.1M tokens against 128K for DeepSeek V3, roughly 8.2x. That is the difference between feeding in a whole repository or a full contract set and having to chunk it. If your work involves documents you cannot split cleanly, this decides it on its own.
Throughput is close enough to ignore — 98/100 versus 85/100. Neither model will feel noticeably quicker in an interactive product, so latency is not a reason to choose between them.
One practical asymmetry: GPT-5.6 Luna offers a batch API at 50% off standard rates, and DeepSeek V3 does not. For anything that does not need an answer immediately — nightly enrichment, backfills, evaluation runs — that discount can be worth more than the difference in list price, and it is easy to overlook when comparing headline rates.
With prices this close (6% apart), pick on fit rather than cost. GPT-5.6 Luna holds the benchmark edge; weigh that against where each one is weakest — coding and creative tasks respectively — and use the calculator above with your own token mix.
What you actually pay
The list price is only the start. Prompt caching, batch processing and long prompts change the bill, and each provider sets them differently. Prices per 1M tokens.
| Pricing term | GPT-5.6 Luna | DeepSeek V3 |
|---|---|---|
| List price (input / output) | $0.20 / $1.20 | $0.27 / $1.10 |
| Cached input | $0.0210% of the input price | — |
| Batch API | 50% off input and output | — |
| Long prompts | Over 272K tokens: $0.40 / $1.80 | — |
| Input with 80% cache hits | $0.056 | — |
Capability scores
iOPTERA editorial scores across 5 categories — informed by public benchmarks, not measured by us
Coding
Reasoning
Extraction
Creative
Vision
Speed Score
Context Window
What Is a Token?
Models don't read words — they process tokens.
A token is roughly 4 characters of English text (~¾ of a word). Your API bill is priced per million tokens — understanding this directly reduces your costs.
Short phrase
"Hello, world!"
- GPT-5.6 Luna
- $0.08
- DeepSeek V3
- $0.11
Business email
One typical email (~200 words)
- GPT-5.6 Luna
- $5.40
- DeepSeek V3
- $7.44
Code file
50-line Python script
- GPT-5.6 Luna
- $8.00
- DeepSeek V3
- $11.02
Prices shown are for 100,000 runs of each workload — one run costs a fraction of a cent on both GPT-5.6 Luna and DeepSeek V3, so the number only becomes meaningful at production volume. Input tokens only; add your output volume in the calculator below.
How to check your token usage
response.usage.total_tokensEvery API response includes a usage object. Sum total_tokens across all calls to get your monthly figure, then use the calculator below.
Your Cost Calculator
Enter your actual monthly token usage to see real savings
Quick Presets
GPT-5.6 Luna
$15.00/mo
$180.00/yr
DeepSeek V3
$15.88/mo
$190.58/yr
Annual Savings
$10.58 saved per year
GPT-5.6 Luna cheaper · $0.8814/mo
Related Comparisons
Explore similar model pairs to find your best fit
GPT-5.6 LunavsGPT-5.6 Terra
$0.20 · $2.00/M input
GPT-5.6 LunavsClaude Haiku
$0.20 · $1.00/M input
GPT-5.6 LunavsGPT-4o Mini
$0.20 · $0.15/M input
GPT-5.6 LunavsGPT-6 Luna
$0.20 · $0.10/M input
GPT-5.6 LunavsGPT-5 Nano
$0.20 · $0.05/M input
GPT-5.6 LunavsGemini 1.5
$0.20 · $0.075/M input
DeepSeek V3vsDeepSeek V4.1
$0.27 · $0.30/M input
DeepSeek V3vsGPT-4o
$0.27 · $2.50/M input