ZMIME
Comparison · 2 models · Updated Nov 2, 2026

GPT OSS 20B vs Seed-OSS-36B-Instruct

Seed-OSS-36B-Instruct comes out ahead, 60 to 52 on our weighted score.

  1. OpenAI

    GPT OSS 20B

    Released Aug 5, 2025

    52/100
    • ECI137.8
    • Price$0.07 / $0.25
    • Context131K
    Full specs Remove GPT OSS 20B
  2. Our pick

    ByteDance Seed

    Seed-OSS-36B-Instruct

    Released Aug 20, 2025

    60/100
    • ECI—
    • Price—
    • Context524K
    Full specs Remove Seed-OSS-36B-Instruct

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Seed-OSS-36B-Instruct is our pick

Seed-OSS-36B-Instruct is the better all-round choice, scoring 60/100 against GPT OSS 20B (52). It leads on capability and 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.

  • CapabilitySeed-OSS-36B-InstructShared benchmarks: Seed-OSS-36B-Instruct 69.5% · GPT OSS 20B 63.0%
  • Lowest priceGPT OSS 20BGPT OSS 20B $0.115 per 1M tokens (3:1 blend) · Seed-OSS-36B-Instruct unpriced
  • Longest contextSeed-OSS-36B-InstructSeed-OSS-36B-Instruct 524,288 · GPT OSS 20B 131,072 tokens
  • Widest inputsSame inputsGPT OSS 20B: Text · Seed-OSS-36B-Instruct: Text
  • Self-hostingAll open weightsEvery model here can be downloaded and run on your own hardware
How the score is built
MeasureWeightGPT OSS 20BSeed-OSS-36B-Instruct
CapabilityShared benchmarks67%6370
Inputs & features20%3535
Context window13%2549
Overall100%52/10060/100

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 OSS 20B vs Seed-OSS-36B-Instruct specifications side by side
SpecificationGPT OSS 20BOpenAISeed-OSS-36B-InstructByteDance Seed
Capability
Capabilities Index (ECI)137.8—
ECI rank#122 of 165—
GPQA DiamondGraduate-level science questions60.8%71.5% (best)
OTIS Mock AIME 2024–2025Competition mathematics65.3%67.5% (best)
Price per million tokens
Input$0.07—
Output$0.25—
Cached input——
Blended (3:1)$0.115—
Long-context rateSame rate—
Price sourceMedian of 37 providers—
Limits
Context window131,072 tokens524,288 tokens (best)
Max output32,768 tokens524,288 tokens (best)
Inputs and features
TextYesYes
ImagesNoNo
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYesYes
Tool callingYesYes
Structured outputNoNo
Availability
WeightsOpenOpenApache 2.0
API model ID——
API providers41—
ReleasedAug 5, 2025Aug 20, 2025
Knowledge cutoffJun 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 OSS 20B$1.20
  • Seed-OSS-36B-Instruct—
04 — Questions

Which should you choose?

Which is better: GPT OSS 20B or Seed-OSS-36B-Instruct?

Seed-OSS-36B-Instruct is the better all-round choice, scoring 60/100 against GPT OSS 20B (52). It leads on capability and 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 OSS 20B or Seed-OSS-36B-Instruct?

GPT OSS 20B is cheaper at $0.07 input / $0.25 output per million tokens (median across 37 API providers). . At a typical mix of three input tokens to one output token, that is $0.115 per million tokens for GPT OSS 20B 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): Seed-OSS-36B-Instruct 69.5% and GPT OSS 20B 63.0%. On individual benchmarks: GPQA Diamond — Seed-OSS-36B-Instruct 71.5%, GPT OSS 20B 60.8%; OTIS Mock AIME 2024–2025 — Seed-OSS-36B-Instruct 67.5%, GPT OSS 20B 65.3%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT OSS 20B and Seed-OSS-36B-Instruct yet, so there is no like-for-like coding score. On overall capability, Seed-OSS-36B-Instruct 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 131,072 for GPT OSS 20B. Maximum output per response: GPT OSS 20B up to 32,768, Seed-OSS-36B-Instruct up to 524,288 tokens.

Which can read images, PDFs, audio or video?

GPT OSS 20B accepts text; Seed-OSS-36B-Instruct accepts text. They handle the same number of input types.

Are any of these open source?

Yes, both publish their weights (Apache 2.0), so you can self-host them.

Which is newer?

Seed-OSS-36B-Instruct is the newest, released Aug 20, 2025. GPT OSS 20B came out Aug 5, 2025. Knowledge cutoff: GPT OSS 20B Jun 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.

05 — Keep comparing

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