GPT-5 vs Seed 1.8
GPT-5 and Seed 1.8 are closely matched at 33.9 and 34.2 on the LLM Stats Score. Seed 1.8 is 5.0x cheaper per token.
OpenAI · ByteDance · Updated for 2026
Which is better?
GPT-5 and Seed 1.8 are closely matched on the overall LLM Stats Score at 33.9 and 34.2.
In the 11 individual benchmarks reported for both models, GPT-5 wins 9; this is a narrower head-to-head signal than the composite indexes.
On price, Seed 1.8 is roughly 5.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5 also accepts a larger context window (400,000 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose GPT-5
- you value its reported benchmark strengths — it wins 9 of 11 exact shared results
- you process long inputs — it offers a 400,000 token context window
Choose Seed 1.8
- cost matters — it's about 5.0x cheaper per token
- you want the most recent training data — it shipped Feb 2026
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
34 reported for GPT-5 · 57 for Seed 1.8
GPT-5 outperforms in 9 benchmarks (AIME 2025, CharXiv-R, ERQA, MMLU, MMMU, MMMU-Pro, Multi-Challenge, SWE-Bench Verified, VideoMMMU), while Seed 1.8 is better at 2 benchmarks (BrowseComp, VideoMME w sub.).
GPT-5 significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5 ($1.25/1M tokens) is 5.0x more expensive than Seed 1.8 ($0.25/1M tokens).
For output processing, GPT-5 ($10.00/1M tokens) is 5.0x more expensive than Seed 1.8 ($2.00/1M tokens).
In conclusion, GPT-5 is more expensive than Seed 1.8.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5 accepts 400,000 input tokens compared to Seed 1.8's 256,000 tokens. Seed 1.8 can generate longer responses up to 256,000 tokens, while GPT-5 is limited to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
Both GPT-5 and Seed 1.8 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5
Seed 1.8
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
GPT-5 was released on 2025-08-07, while Seed 1.8 was released on 2026-02-17.
Seed 1.8 is 6 months newer than GPT-5.
Aug 7, 2025
1.1 years ago
Feb 17, 2026
6 months ago
6mo newerKnowledge Cutoff
When training data ends
GPT-5 has a documented knowledge cutoff of 2024-09-30, while Seed 1.8's cutoff date is not specified.
We can confirm GPT-5's training data extends to 2024-09-30, but cannot make a direct comparison without Seed 1.8's cutoff date.
Sep 2024
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Provider Availability
GPT-5 is available from OpenAI. Seed 1.8 is available from DeepInfra.
GPT-5
Seed 1.8
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-5 and Seed 1.8 side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-5 vs Seed 1.8.