DeepSeek V4.1 Flash vs GPT-6 Luna

As of November 12, 2026, GPT-6 Luna costs 11% more per input token than DeepSeek V4.1 Flash ($0.10 vs $0.09 per 1M) and has a 922K-token context window versus 1M.

Prices from LiteLLM's price fileChecked November 12, 2026

DeepSeek V4.1 Flash vs GPT-6 Luna side by side

Headline prices in US dollars per 1M tokens: each model's own lab where it sells it, otherwise its cheapest provider. Source: LiteLLM model price file, as of November 12, 2026.
	DeepSeek V4.1 Flash	GPT-6 Luna
Input, per 1M tokens	$0.09	$0.10
Output, per 1M tokens	$0.30	$0.50
Cache read, per 1M tokens	$0.006	$0.01
Cache write, per 1M tokens	–	$0.125
Context window	1,048,576 tokens	922,000 tokens
Max output	1,048,576 tokens	128,000 tokens
Image input	Yes	Yes
Tool calling	Yes	Yes
Structured output (JSON)	Yes	Yes
Prompt caching	Yes	Yes
Reasoning	Yes	Yes
Providers on LiteLLM	25	13
Price shown is from	Sail	OpenAI
Added to LiteLLM	September 11, 2026	September 22, 2026

Cheapest provider for each

DeepSeek V4.1 Flash: Sail at $0.09 input and $0.30 output per 1M tokens (sail/deepseek-ai/DeepSeek-V4.1-Flash)
GPT-6 Luna: OpenAI at $0.10 input and $0.50 output per 1M tokens (gpt-6-luna)

Benchmark scores

From the Epoch AI Benchmarking Hub (CC BY 4.0), data as of October 13, 2026. Some results were run by Epoch and others collected by Epoch from each benchmark's own leaderboard, linked in the first column. Each model's best reported reasoning setting is shown in brackets. Higher is better. Only benchmarks with a score for both models are shown.
Benchmark	DeepSeek V4.1 Flash	GPT-6 Luna
Overall
Epoch Capabilities Index	156.7	156.4
Coding and agents
FrontierCode	43.9% (high)	42.4% (max)
APEX-Agents	39.5%	44.3% (max)
Reasoning and knowledge
GPQA Diamond	89.8% (max)	90.5% (max)
ARC-AGI-2	72.9% (max)	59.3% (max)
SimpleQA Verified	42.9% (max)	41.4% (max)
Math
FrontierMath (tiers 1-3)	67.4% (max)	78.9% (max)
FrontierMath (tier 4)	26.8% (max)	56.1% (max)
OTIS Mock AIME 2024-2025	98.3% (max)	98.9% (max)

When to pick which

Pick DeepSeek V4.1 Flash for

Costs 10% less per input token: $0.09 vs $0.10 per 1M.
Larger context window: 1,048,576 vs 922,000 tokens.

From differences in the data above only; where the data is equal, no reason is given.

Call DeepSeek V4.1 Flash or GPT-6 Luna with LiteLLM

Both use the OpenAI format through LiteLLM, so switching is a model name change. Set each provider's API key in the environment first.

Python SDK

from litellm import completion

messages = [{"role": "user", "content": "Hello!"}]

# DeepSeek V4.1 Flash
response = completion(model="sail/deepseek-ai/DeepSeek-V4.1-Flash", messages=messages)

# GPT-6 Luna
response = completion(model="gpt-6-luna", messages=messages)

# DeepSeek V4.1 Flash, falling back to GPT-6 Luna if the call fails
response = completion(model="sail/deepseek-ai/DeepSeek-V4.1-Flash", messages=messages, fallbacks=["gpt-6-luna"])

FAQ

Which is cheaper, DeepSeek V4.1 Flash or GPT-6 Luna?

DeepSeek V4.1 Flash is cheaper at 3 input tokens per output token: $0.1425 per 1M tokens blended ($0.09 input, $0.30 output), versus $0.20 ($0.10 and $0.50) for GPT-6 Luna, as of November 12, 2026.

Which has the larger context window, DeepSeek V4.1 Flash or GPT-6 Luna?

DeepSeek V4.1 Flash has the larger context window: 1,048,576 tokens, versus 922,000 for GPT-6 Luna.

Can I switch from DeepSeek V4.1 Flash to GPT-6 Luna without changing my code?

Yes. Through LiteLLM both use the OpenAI format, so switching means changing the model name from "sail/deepseek-ai/DeepSeek-V4.1-Flash" to "gpt-6-luna", or pointing a LiteLLM gateway model alias at the other model. You can also use one as a fallback for the other.