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Comparison · 2 models · Updated Nov 2, 2026

GPT OSS 120B vs Gemini 2.5 Flash Preview 05-20

Gemini 2.5 Flash Preview 05-20 comes out ahead, 67 to 58 on our weighted score, though GPT OSS 120B is 2.3× cheaper per token.

  1. OpenAI

    GPT OSS 120B

    Released Aug 5, 2025

    58/100
    • ECI139.8
    • Price$0.15 / $0.60
    • Context131K
    Full specs Remove GPT OSS 120B
  2. Our pick

    Google

    Gemini 2.5 Flash Preview 05-20

    Released May 20, 2025

    67/100
    • ECI141.5
    • Price$0.146 / $1.96
    • Context1.05M
    Full specs Remove Gemini 2.5 Flash Preview 05-20

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Gemini 2.5 Flash Preview 05-20 is our pick

Gemini 2.5 Flash Preview 05-20 is the better all-round choice, scoring 67/100 against GPT OSS 120B (58). It leads on capability, inputs & features and context window. GPT OSS 120B wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGemini 2.5 Flash Preview 05-20Capabilities Index (ECI): Gemini 2.5 Flash Preview 05-20 141.5 · GPT OSS 120B 139.8
  • Lowest priceGPT OSS 120BGPT OSS 120B $0.263 · Gemini 2.5 Flash Preview 05-20 $0.60 per 1M tokens (3:1 blend)
  • Longest contextGemini 2.5 Flash Preview 05-20Gemini 2.5 Flash Preview 05-20 1,048,576 · GPT OSS 120B 131,072 tokens
  • Widest inputsGemini 2.5 Flash Preview 05-20GPT OSS 120B: Text · Gemini 2.5 Flash Preview 05-20: Text, Images, PDFs, Audio, Video
  • Self-hostingGPT OSS 120BPublishes downloadable weights
How the score is built
MeasureWeightGPT OSS 120BGemini 2.5 Flash Preview 05-20
CapabilityCapabilities Index (ECI)50%6466
Price25%7458
Inputs & features15%3590
Context window10%2561
Overall100%58/10067/100
02 — Side by side

Every spec in one table

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

GPT OSS 120B vs Gemini 2.5 Flash Preview 05-20 specifications side by side
SpecificationGPT OSS 120BOpenAIGemini 2.5 Flash Preview 05-20Google
Capability
Capabilities Index (ECI)139.8141.5 (best)
ECI rank#114 of 165#106 of 165 (best)
GPQA DiamondGraduate-level science questions75.8%—
OTIS Mock AIME 2024–2025Competition mathematics88.9% (best)70.8%
Price per million tokens
Input$0.15$0.146 (best)
Output$0.60 (best)$1.96
Cached input——
Blended (3:1)$0.263 (best)$0.60
Long-context rateSame rateSame rate
Price sourceMedian of 65 providersMedian of 2 providers
Limits
Context window131,072 tokens1,048,576 tokens (best)
Max output32,768 tokens65,536 tokens (best)
Inputs and features
TextYesYes
ImagesNoYes
PDFsNoYes
AudioNoYes
VideoNoYes
ReasoningYesYes
Tool callingYesYes
Structured outputNoNo
Availability
WeightsOpenProprietary
API model ID——
API providers67 (best)2
ReleasedAug 5, 2025May 20, 2025
Knowledge cutoffJun 2024Jan 2025
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 120B$2.70
  • Gemini 2.5 Flash Preview 05-20$5.39
04 — Questions

Which should you choose?

Which is better: GPT OSS 120B or Gemini 2.5 Flash Preview 05-20?

Gemini 2.5 Flash Preview 05-20 is the better all-round choice, scoring 67/100 against GPT OSS 120B (58). It leads on capability, inputs & features and context window. GPT OSS 120B wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT OSS 120B or Gemini 2.5 Flash Preview 05-20?

GPT OSS 120B is cheaper at $0.15 input / $0.60 output per million tokens (median across 65 API providers). Gemini 2.5 Flash Preview 05-20 costs $0.146 input / $1.96 output per million tokens (median across 2 API providers). At a typical mix of three input tokens to one output token, that is $0.263 per million tokens for GPT OSS 120B versus $0.60 for Gemini 2.5 Flash Preview 05-20 (2.3× as much).

Which scores higher on benchmarks?

Gemini 2.5 Flash Preview 05-20 scores higher on the Capabilities Index (ECI): Gemini 2.5 Flash Preview 05-20 141.5 (#106 of 165) and GPT OSS 120B 139.8 (#114 of 165). The confidence ranges of the top two overlap (139.3–142.9 vs 135.6–142.2), so treat the gap as small. On individual benchmarks: OTIS Mock AIME 2024–2025 — GPT OSS 120B 88.9%, Gemini 2.5 Flash Preview 05-20 70.8%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT OSS 120B and Gemini 2.5 Flash Preview 05-20 yet, so there is no like-for-like coding score. On overall capability, Gemini 2.5 Flash Preview 05-20 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?

Gemini 2.5 Flash Preview 05-20 has the largest context window at 1,048,576 tokens, against 131,072 for GPT OSS 120B. Maximum output per response: GPT OSS 120B up to 32,768, Gemini 2.5 Flash Preview 05-20 up to 65,536 tokens.

Which can read images, PDFs, audio or video?

GPT OSS 120B accepts text; Gemini 2.5 Flash Preview 05-20 accepts text, images, PDFs, audio and video. Gemini 2.5 Flash Preview 05-20 handles the widest range of inputs.

Are any of these open source?

GPT OSS 120B publishes its weights and can be self-hosted; Gemini 2.5 Flash Preview 05-20 is proprietary.

Which is newer?

GPT OSS 120B is the newest, released Aug 5, 2025. Gemini 2.5 Flash Preview 05-20 came out May 20, 2025. Knowledge cutoff: GPT OSS 120B Jun 2024, Gemini 2.5 Flash Preview 05-20 Jan 2025.

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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