ZMIME
Comparison · 2 models · Updated Nov 2, 2026

Seed-OSS-36B-Instruct vs GPT-5 Nano

GPT-5 Nano comes out ahead, 70 to 60 on our weighted score, and it is the cheaper option too.

  1. ByteDance Seed

    Seed-OSS-36B-Instruct

    Released Aug 20, 2025

    60/100
    • ECI—
    • Price—
    • Context524K
  2. Our pick

    OpenAI

    GPT-5 Nano

    Released Aug 7, 2025

    70/100
    • ECI139.3
    • Price$0.05 / $0.40
    • Context400K
  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GPT-5 Nano is our pick

GPT-5 Nano is the better all-round choice, scoring 70/100 against Seed-OSS-36B-Instruct (60). It leads on capability and inputs & features. Seed-OSS-36B-Instruct wins on context window. The score weighs capability 67%, inputs & features 20%, context window 13%. Capability uses the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025), because Seed-OSS-36B-Instruct has no Capabilities Index score yet.

  • CapabilityGPT-5 NanoShared benchmarks: GPT-5 Nano 75.3% · Seed-OSS-36B-Instruct 69.5%
  • Lowest priceGPT-5 NanoGPT-5 Nano $0.138 per 1M tokens (3:1 blend) · Seed-OSS-36B-Instruct unpriced
  • Longest contextSeed-OSS-36B-InstructSeed-OSS-36B-Instruct 524,288 · GPT-5 Nano 400,000 tokens
  • Widest inputsGPT-5 NanoSeed-OSS-36B-Instruct: Text · GPT-5 Nano: Text, Images
  • Self-hostingSeed-OSS-36B-InstructPublishes downloadable weights (Apache 2.0)
How the score is built
MeasureWeightSeed-OSS-36B-InstructGPT-5 Nano
CapabilityShared benchmarks67%7075
Inputs & features20%3570
Context window13%4944
Overall100%60/10070/100

Left out because at least one model lacks the data: price. The remaining weights were rescaled.

02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

Seed-OSS-36B-Instruct vs GPT-5 Nano specifications side by side
SpecificationSeed-OSS-36B-InstructByteDance SeedGPT-5 NanoOpenAI
Capability
Capabilities Index (ECI)—139.3
ECI rank—#116 of 165
GPQA DiamondGraduate-level science questions71.5% (best)69.4%
FrontierMath Tiers 1–3Research-level mathematics—20.0%
OTIS Mock AIME 2024–2025Competition mathematics67.5%81.1% (best)
SimpleQA VerifiedShort factual questions—11.7%
Price per million tokens
Input—$0.05
Output—$0.40
Cached input—$0.005
Blended (3:1)—$0.138
Long-context rate—Same rate
Price source—Official OpenAI API
Limits
Context window524,288 tokens (best)400,000 tokens
Max output524,288 tokens (best)128,000 tokens
Inputs and features
TextYesYes
ImagesNoYes
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYesYesminimal · low · medium · high
Tool callingYesYes
Structured outputNoYes
Availability
WeightsOpenApache 2.0Proprietary
API model ID—gpt-5-nano
API providers—30
ReleasedAug 20, 2025Aug 7, 2025
Knowledge cutoffJul 2024May 30, 2024
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • Seed-OSS-36B-Instruct—
  • GPT-5 Nano$1.30
04 — Questions

Which should you choose?

Which is better: Seed-OSS-36B-Instruct or GPT-5 Nano?

GPT-5 Nano is the better all-round choice, scoring 70/100 against Seed-OSS-36B-Instruct (60). It leads on capability and inputs & features. Seed-OSS-36B-Instruct wins on context window. The score weighs capability 67%, inputs & features 20%, context window 13%. Capability uses the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025), because Seed-OSS-36B-Instruct has no Capabilities Index score yet.

Which is cheaper, Seed-OSS-36B-Instruct or GPT-5 Nano?

GPT-5 Nano is cheaper at $0.05 input / $0.40 output per million tokens (official OpenAI API price). . At a typical mix of three input tokens to one output token, that is $0.138 per million tokens for GPT-5 Nano versus . Seed-OSS-36B-Instruct has no published per-token price.

Which scores higher on benchmarks?

Not every model here has a Capabilities Index score, so we compare the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025): GPT-5 Nano 75.3% and Seed-OSS-36B-Instruct 69.5%. On individual benchmarks: GPQA Diamond — Seed-OSS-36B-Instruct 71.5%, GPT-5 Nano 69.4%; OTIS Mock AIME 2024–2025 — GPT-5 Nano 81.1%, Seed-OSS-36B-Instruct 67.5%.

Which is better for coding?

There are no published SWE-bench Verified results for Seed-OSS-36B-Instruct and GPT-5 Nano yet, so there is no like-for-like coding score. On overall capability, GPT-5 Nano leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.

Which has the bigger context window?

Seed-OSS-36B-Instruct has the largest context window at 524,288 tokens, against 400,000 for GPT-5 Nano. Maximum output per response: Seed-OSS-36B-Instruct up to 524,288, GPT-5 Nano up to 128,000 tokens.

Which can read images, PDFs, audio or video?

Seed-OSS-36B-Instruct accepts text; GPT-5 Nano accepts text and images. GPT-5 Nano handles the widest range of inputs.

Are any of these open source?

Seed-OSS-36B-Instruct publishes its weights (Apache 2.0) and can be self-hosted; GPT-5 Nano is proprietary.

Which is newer?

Seed-OSS-36B-Instruct is the newest, released Aug 20, 2025. GPT-5 Nano came out Aug 7, 2025. Knowledge cutoff: Seed-OSS-36B-Instruct Jul 2024, GPT-5 Nano May 30, 2024.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.