ZMIME
Comparison · 2 models · Updated Nov 2, 2026

GPT OSS 20B vs Gemma 3 27B IT

GPT OSS 20B comes out ahead, 61 to 57 on our weighted score, and it is the cheaper option too.

  1. Our pick

    OpenAI

    GPT OSS 20B

    Released Aug 5, 2025

    61/100
    • ECI137.8
    • Price$0.07 / $0.25
    • Context131K
    Full specs Remove GPT OSS 20B

  2. Google

    Gemma 3 27B IT

    Released Mar 12, 2025

    57/100
    • ECI129.9
    • Price$0.11 / $0.30
    • Context131K
    Full specs Remove Gemma 3 27B IT

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GPT OSS 20B is our pick

GPT OSS 20B is the better all-round choice, scoring 61/100 against Gemma 3 27B IT (57). It leads on capability and price. Gemma 3 27B IT wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT OSS 20BCapabilities Index (ECI): GPT OSS 20B 137.8 · Gemma 3 27B IT 129.9
  • Lowest priceGPT OSS 20BGPT OSS 20B $0.115 · Gemma 3 27B IT $0.157 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameGPT OSS 20B 131,072 · Gemma 3 27B IT 131,072 tokens
  • Widest inputsGemma 3 27B ITGPT OSS 20B: Text · Gemma 3 27B IT: Text, Images
  • Self-hostingAll open weightsEvery model here can be downloaded and run on your own hardware
How the score is built
MeasureWeightGPT OSS 20BGemma 3 27B IT
CapabilityCapabilities Index (ECI)50%6152
Price25%9084
Inputs & features15%3550
Context window10%2525
Overall100%61/10057/100
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 Gemma 3 27B IT specifications side by side
SpecificationGPT OSS 20BOpenAIGemma 3 27B ITGoogle
Capability
Capabilities Index (ECI)137.8 (best)129.9
ECI rank#122 of 165 (best)#137 of 165
GPQA DiamondGraduate-level science questions60.8% (best)47.7%
OTIS Mock AIME 2024–2025Competition mathematics65.3% (best)22.5%
Price per million tokens
Input$0.07 (best)$0.11
Output$0.25 (best)$0.30
Cached input——
Blended (3:1)$0.115 (best)$0.157
Long-context rateSame rateSame rate
Price sourceMedian of 37 providersMedian of 16 providers
Limits
Context window131,072 tokens131,072 tokens
Max output32,768 tokens131,072 tokens (best)
Inputs and features
TextYesYes
ImagesNoYes
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYesNo
Tool callingYesYes
Structured outputNoNo
Availability
WeightsOpenOpen
API model ID——
API providers41 (best)17
ReleasedAug 5, 2025Mar 12, 2025
Knowledge cutoffJun 2024Aug 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
  • Gemma 3 27B IT$1.69
04 — Questions

Which should you choose?

Which is better: GPT OSS 20B or Gemma 3 27B IT?

GPT OSS 20B is the better all-round choice, scoring 61/100 against Gemma 3 27B IT (57). It leads on capability and price. Gemma 3 27B IT wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT OSS 20B or Gemma 3 27B IT?

GPT OSS 20B is cheaper at $0.07 input / $0.25 output per million tokens (median across 37 API providers). Gemma 3 27B IT costs $0.11 input / $0.30 output per million tokens (median across 16 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 $0.157 for Gemma 3 27B IT (1.4× as much).

Which scores higher on benchmarks?

GPT OSS 20B scores higher on the Capabilities Index (ECI): GPT OSS 20B 137.8 (#122 of 165) and Gemma 3 27B IT 129.9 (#137 of 165). Their confidence ranges do not overlap (133.1–139.7 vs 124.2–132.1), so the gap is a real one. On individual benchmarks: GPQA Diamond — GPT OSS 20B 60.8%, Gemma 3 27B IT 47.7%; OTIS Mock AIME 2024–2025 — GPT OSS 20B 65.3%, Gemma 3 27B IT 22.5%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT OSS 20B and Gemma 3 27B IT yet, so there is no like-for-like coding score. On overall capability, GPT OSS 20B 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?

GPT OSS 20B and Gemma 3 27B IT share the same 131,072-token context window. Maximum output per response: GPT OSS 20B up to 32,768, Gemma 3 27B IT up to 131,072 tokens.

Which can read images, PDFs, audio or video?

GPT OSS 20B accepts text; Gemma 3 27B IT accepts text and images. Gemma 3 27B IT handles the widest range of inputs.

Are any of these open source?

Yes, both publish their weights, so you can self-host them.

Which is newer?

GPT OSS 20B is the newest, released Aug 5, 2025. Gemma 3 27B IT came out Mar 12, 2025. Knowledge cutoff: GPT OSS 20B Jun 2024, Gemma 3 27B IT Aug 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

Related comparisons