ZMIME
Comparison · 2 models · Updated Nov 2, 2026

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

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

  1. Our pick

    OpenAI

    GPT-5 Nano

    Released Aug 7, 2025

    70/100
    • ECI139.3
    • Price$0.05 / $0.40
    • Context400K
  2. ByteDance Seed

    Seed-OSS-36B-Instruct

    Released Aug 20, 2025

    60/100
    • ECI—
    • Price—
    • Context524K
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    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 NanoGPT-5 Nano: Text, Images · Seed-OSS-36B-Instruct: Text
  • Self-hostingSeed-OSS-36B-InstructPublishes downloadable weights (Apache 2.0)
How the score is built
MeasureWeightGPT-5 NanoSeed-OSS-36B-Instruct
CapabilityShared benchmarks67%7570
Inputs & features20%7035
Context window13%4449
Overall100%70/10060/100

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.

GPT-5 Nano vs Seed-OSS-36B-Instruct specifications side by side
SpecificationGPT-5 NanoOpenAISeed-OSS-36B-InstructByteDance Seed
Capability
Capabilities Index (ECI)139.3—
ECI rank#116 of 165—
GPQA DiamondGraduate-level science questions69.4%71.5% (best)
FrontierMath Tiers 1–3Research-level mathematics20.0%—
OTIS Mock AIME 2024–2025Competition mathematics81.1% (best)67.5%
SimpleQA VerifiedShort factual questions11.7%—
Price per million tokens
Input$0.05—
Output$0.40—
Cached input$0.005—
Blended (3:1)$0.138—
Long-context rateSame rate—
Price sourceOfficial OpenAI API—
Limits
Context window400,000 tokens524,288 tokens (best)
Max output128,000 tokens524,288 tokens (best)
Inputs and features
TextYesYes
ImagesYesNo
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYesminimal · low · medium · highYes
Tool callingYesYes
Structured outputYesNo
Availability
WeightsProprietaryOpenApache 2.0
API model IDgpt-5-nano—
API providers30—
ReleasedAug 7, 2025Aug 20, 2025
Knowledge cutoffMay 30, 2024Jul 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.

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

Which should you choose?

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

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

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 GPT-5 Nano and Seed-OSS-36B-Instruct 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: GPT-5 Nano up to 128,000, Seed-OSS-36B-Instruct up to 524,288 tokens.

Which can read images, PDFs, audio or video?

GPT-5 Nano accepts text and images; Seed-OSS-36B-Instruct accepts text. 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: GPT-5 Nano May 30, 2024, Seed-OSS-36B-Instruct Jul 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.