GPT-5.6 Luna vs Qwen3.5 Flash

Two models head to head

GPT-5.6 Luna and Qwen3.5 Flash are two budget models, built for high volumes at a low price, one from OpenAI, the other from Alibaba Cloud (Qwen). GPT-5.6 Luna was released on July 9, 2026, Qwen3.5 Flash on February 23, 2026.

All figures below come from public sources checked on October 22, 2026: models.dev and OpenRouter for prices and capabilities, Epoch AI for scores.

Which one is more capable?

On our capability index, GPT-5.6 Luna scores 79.6 out of 100 and Qwen3.5 Flash 62.6. GPT-5.6 Luna leads by 17 points.

On the 3 benchmarks reported for both, GPT-5.6 Luna wins 3 times and Qwen3.5 Flash 0:

• GPQA Diamond (PhD-level science questions): GPT-5.6 Luna 91.6%, Qwen3.5 Flash 82.3%
• OTIS Mock AIME (competition mathematics problems): GPT-5.6 Luna 98.3%, Qwen3.5 Flash 84.4%
• FrontierMath (very hard research-level mathematics): GPT-5.6 Luna 82.1%, Qwen3.5 Flash 18.2%

Budget

GPT-5.6 Luna costs $0.20 per million input tokens and $1.2 per million output tokens; Qwen3.5 Flash costs $0.10 and $0.40.

For a typical agent task (read 20,000 tokens, write 2,000), expect $0.006 with GPT-5.6 Luna versus $0.003 with Qwen3.5 Flash. Qwen3.5 Flash is 2.3 times cheaper, a gap that adds up quickly over 1,000 tasks: $3.6 difference.

Run the numbers with your own volumes in the agent cost calculator.

Context and capabilities

GPT-5.6 Luna reads more in one go: 1,050,000 tokens of context (roughly 1,575 pages), versus 1,000,000 for Qwen3.5 Flash.

Reasoning mode: GPT-5.6 Luna yes, Qwen3.5 Flash yes. Tool calling: GPT-5.6 Luna yes, Qwen3.5 Flash yes. Image input: GPT-5.6 Luna yes, Qwen3.5 Flash yes.

Neither publishes its weights: both are used through an API.

In short

Our reading of the data:

• Choose GPT-5.6 Luna for a higher capability index and a more recent release.
• Choose Qwen3.5 Flash for a lower cost.

This verdict relies on public figures; it does not replace a trial on your own tasks.