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Comparison · 2 models · Updated Nov 2, 2026

GPT OSS 20B vs DeepSeek-V3.1

GPT OSS 20B comes out ahead, 61 to 56 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. DeepSeek

    DeepSeek-V3.1

    Released Aug 21, 2025

    56/100
    • ECI139.8
    • Price$0.27 / $1.00
    • Context131K
    Full specs Remove DeepSeek-V3.1

  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 DeepSeek-V3.1 (56). It leads on price. DeepSeek-V3.1 wins on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityDeepSeek-V3.1Capabilities Index (ECI): DeepSeek-V3.1 139.8 · GPT OSS 20B 137.8
  • Lowest priceGPT OSS 20BGPT OSS 20B $0.115 · DeepSeek-V3.1 $0.453 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameGPT OSS 20B 131,072 · DeepSeek-V3.1 131,072 tokens
  • Widest inputsSame inputsGPT OSS 20B: Text · DeepSeek-V3.1: Text
  • Self-hostingAll open weightsEvery model here can be downloaded and run on your own hardware
How the score is built
MeasureWeightGPT OSS 20BDeepSeek-V3.1
CapabilityCapabilities Index (ECI)50%6164
Price25%9063
Inputs & features15%3535
Context window10%2525
Overall100%61/10056/100
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 DeepSeek-V3.1 specifications side by side
SpecificationGPT OSS 20BOpenAIDeepSeek-V3.1DeepSeek
Capability
Capabilities Index (ECI)137.8139.8 (best)
ECI rank#122 of 165#113 of 165 (best)
GPQA DiamondGraduate-level science questions60.8%—
OTIS Mock AIME 2024–2025Competition mathematics65.3%—
Price per million tokens
Input$0.07 (best)$0.27
Output$0.25 (best)$1.00
Cached input——
Blended (3:1)$0.115 (best)$0.453
Long-context rateSame rateSame rate
Price sourceMedian of 37 providersMedian of 19 providers
Limits
Context window131,072 tokens131,072 tokens
Max output32,768 tokens (best)8,192 tokens
Inputs and features
TextYesYes
ImagesNoNo
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYesYes
Tool callingYesYes
Structured outputNoNo
Availability
WeightsOpenOpenMIT License
API model ID——
API providers41 (best)19
ReleasedAug 5, 2025Aug 21, 2025
Knowledge cutoffJun 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
  • DeepSeek-V3.1$4.70
04 — Questions

Which should you choose?

Which is better: GPT OSS 20B or DeepSeek-V3.1?

GPT OSS 20B is the better all-round choice, scoring 61/100 against DeepSeek-V3.1 (56). It leads on price. DeepSeek-V3.1 wins on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT OSS 20B or DeepSeek-V3.1?

GPT OSS 20B is cheaper at $0.07 input / $0.25 output per million tokens (median across 37 API providers). DeepSeek-V3.1 costs $0.27 input / $1.00 output per million tokens (median across 19 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 $0.453 for DeepSeek-V3.1 (3.9× as much).

Which scores higher on benchmarks?

DeepSeek-V3.1 scores higher on the Capabilities Index (ECI): DeepSeek-V3.1 139.8 (#113 of 165) and GPT OSS 20B 137.8 (#122 of 165). The confidence ranges of the top two overlap (135.6–143.2 vs 133.1–139.7), so treat the gap as small.

Which is better for coding?

There are no published SWE-bench Verified results for GPT OSS 20B and DeepSeek-V3.1 yet, so there is no like-for-like coding score. On overall capability, DeepSeek-V3.1 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 DeepSeek-V3.1 share the same 131,072-token context window. Maximum output per response: GPT OSS 20B up to 32,768, DeepSeek-V3.1 up to 8,192 tokens.

Which can read images, PDFs, audio or video?

GPT OSS 20B accepts text; DeepSeek-V3.1 accepts text. They handle the same number of input types.

Are any of these open source?

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

Which is newer?

DeepSeek-V3.1 is the newest, released Aug 21, 2025. GPT OSS 20B came out Aug 5, 2025. Knowledge cutoff: GPT OSS 20B Jun 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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