ByteDance Seed: Seed 2.1 Turbo vs OpenAI: GPT-5.6 Luna (batch)

For a sample job of 1 million input tokens and 250,000 output tokens, GPT-5.6 Luna (batch) costs $0.25 and Seed 2.1 Turbo costs $1.12, so GPT-5.6 Luna (batch) is about 4.5 times cheaper for the same work.

GPT-5.6 Luna (batch) reads up to 1,050,000 tokens at once, roughly 1,575 pages of text, against about 393 pages for Seed 2.1 Turbo.

Only Seed 2.1 Turbo offers video input.

Across the 20 tasks where they differ, GPT-5.6 Luna (batch) on 20 (SQL Generation, Code Review, Code Completion and others).

Seed 2.1 Turbo was released in August 2026 and GPT-5.6 Luna (batch) in July 2026.

Pick Seed 2.1 Turbo if you need video input; pick GPT-5.6 Luna (batch) if you need lower cost, long documents or the stronger all-round task scores.

Costs use current list prices per million tokens; page counts assume about 0.75 words per token and 500 words per page.