GPT-5.4 nano vs Qwen3.5 Flash

Two models head to head

GPT-5.4 nano 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-5.4 nano was released on March 17, 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.

What the benchmarks say

On our capability index, GPT-5.4 nano scores 71.7 out of 100 and Qwen3.5 Flash 62.6. GPT-5.4 nano leads by 9.1 points.

On the 3 benchmarks reported for both, GPT-5.4 nano wins 2 times and Qwen3.5 Flash 1:

• GPQA Diamond (PhD-level science questions): GPT-5.4 nano 78.5%, Qwen3.5 Flash 82.3%
• OTIS Mock AIME (competition mathematics problems): GPT-5.4 nano 87.8%, Qwen3.5 Flash 84.4%
• FrontierMath (very hard research-level mathematics): GPT-5.4 nano 44.9%, Qwen3.5 Flash 18.2%

Budget

GPT-5.4 nano costs $0.20 per million input tokens and $1.25 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 $0.007 with GPT-5.4 nano 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: $3.7 difference.

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

Context and capabilities

Qwen3.5 Flash reads more in one go: 1,000,000 tokens of context (roughly 1,500 pages), versus 400,000 for GPT-5.4 nano.

Reasoning mode: GPT-5.4 nano yes, Qwen3.5 Flash yes. Tool calling: GPT-5.4 nano yes, Qwen3.5 Flash yes. Image input: GPT-5.4 nano yes, Qwen3.5 Flash yes.

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

In short

Our reading of the data:

• Choose GPT-5.4 nano for a higher capability index.
• Choose Qwen3.5 Flash for a lower cost and a larger context window.

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