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Comparison · 3 models · Updated Oct 4, 2026

Gemini 2.5 Flash vs GPT OSS 120B vs DeepSeek-V3.1

Gemini 2.5 Flash comes out ahead, 68 to 61 and 55 on our weighted score, though GPT OSS 120B is 3.2× cheaper per token.

  1. Our pick

    Google

    Gemini 2.5 Flash

    Released Jun 17, 2025

    68/100
    • ECI140.8
    • Price$0.30 / $2.50
    • Context1.05M
    Full specs Remove Gemini 2.5 Flash

  2. OpenAI

    GPT OSS 120B

    Released Aug 5, 2025

    61/100
    • ECI140.0
    • Price$0.15 / $0.60
    • Context131K
    Full specs Remove GPT OSS 120B

  3. DeepSeek

    DeepSeek-V3.1

    Released Aug 21, 2025

    55/100
    • ECI139.9
    • Price$0.385 / $1.25
    • Context131K
    Full specs Remove DeepSeek-V3.1
01 — Verdict

Gemini 2.5 Flash is our pick

Gemini 2.5 Flash is the better all-round choice, scoring 68/100 against GPT OSS 120B (61) and DeepSeek-V3.1 (55). It leads on 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 FlashCapabilities Index (ECI): Gemini 2.5 Flash 140.8 · GPT OSS 120B 140.0 · DeepSeek-V3.1 139.9
  • Lowest priceGPT OSS 120BGPT OSS 120B $0.263 · DeepSeek-V3.1 $0.601 · Gemini 2.5 Flash $0.85 per 1M tokens (3:1 blend)
  • Longest contextGemini 2.5 FlashGemini 2.5 Flash 1,048,576 · GPT OSS 120B 131,072 · DeepSeek-V3.1 131,072 tokens
  • Widest inputsGemini 2.5 FlashGemini 2.5 Flash: Text, Images, PDFs, Audio, Video · GPT OSS 120B: Text · DeepSeek-V3.1: Text
  • Self-hostingGPT OSS 120B and DeepSeek-V3.1Publishes downloadable weights (MIT License)
How the score is built
MeasureWeightGemini 2.5 FlashGPT OSS 120BDeepSeek-V3.1
CapabilityCapabilities Index (ECI)50%676565
Price25%537760
Inputs & features15%1004535
Context window10%612424
Overall100%68/10061/10055/100
02 — Side by side

Every spec in one table

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

Gemini 2.5 Flash vs GPT OSS 120B vs DeepSeek-V3.1 specifications side by side
SpecificationGemini 2.5 FlashGoogleGPT OSS 120BOpenAIDeepSeek-V3.1DeepSeek
Capability
Capabilities Index (ECI)140.8 (best)140.0139.9
ECI rank#97 of 148 (best)#99 of 148#100 of 148
GPQA DiamondGraduate-level science questions—75.8%—
OTIS Mock AIME 2024–2025Competition mathematics—88.9%—
Price per million tokens
Input$0.30$0.15 (best)$0.385
Output$2.50$0.60 (best)$1.25
Cached input$0.03——
Blended (3:1)$0.85$0.263 (best)$0.601
Long-context rateSame rateSame rateSame rate
Price sourceOfficial Google APIMedian of 36 providersMedian of 8 providers
Limits
Context window1,048,576 tokens (best)131,072 tokens131,072 tokens
Max output65,536 tokens (best)32,768 tokens8,192 tokens
Inputs and features
TextYesYesYes
ImagesYesNoNo
PDFsYesNoNo
AudioYesNoNo
VideoYesNoNo
ReasoningYesYesYes
Tool callingYesYesYes
Structured outputYesYesNo
Availability
WeightsProprietaryOpenOpenMIT License
API model IDgemini-2.5-flash——
API providers2239 (best)8
ReleasedJun 17, 2025Aug 5, 2025Aug 21, 2025
Knowledge cutoffJan 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.

  • Gemini 2.5 Flash$8.00
  • GPT OSS 120B$2.70
  • DeepSeek-V3.1$6.35
04 — Questions

Which should you choose?

Which is better: Gemini 2.5 Flash, GPT OSS 120B or DeepSeek-V3.1?

Gemini 2.5 Flash is the better all-round choice, scoring 68/100 against GPT OSS 120B (61) and DeepSeek-V3.1 (55). It leads on 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, Gemini 2.5 Flash, GPT OSS 120B or DeepSeek-V3.1?

GPT OSS 120B is cheaper at $0.15 input / $0.60 output per million tokens (median across 36 API providers). DeepSeek-V3.1 costs $0.385 input / $1.25 output per million tokens (median across 8 API providers); Gemini 2.5 Flash costs $0.30 input / $2.50 output per million tokens (official Google API price). At a typical mix of three input tokens to one output token, that is $0.263 per million tokens for GPT OSS 120B versus $0.601 for DeepSeek-V3.1 (2.3× as much) and $0.85 for Gemini 2.5 Flash (3.2× as much).

Which scores higher on benchmarks?

Gemini 2.5 Flash scores higher on the Capabilities Index (ECI): Gemini 2.5 Flash 140.8 (#97 of 148), GPT OSS 120B 140.0 (#99 of 148) and DeepSeek-V3.1 139.9 (#100 of 148). The confidence ranges of the top two overlap (138.5–142.3 vs 135.3–142.3), so treat the gap as small.

Which is better for coding?

There are no published SWE-bench Verified results for Gemini 2.5 Flash, GPT OSS 120B and DeepSeek-V3.1 yet, so there is no like-for-like coding score. On overall capability, Gemini 2.5 Flash leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.

Which has the bigger context window?

Gemini 2.5 Flash has the largest context window at 1,048,576 tokens, against 131,072 for GPT OSS 120B and 131,072 for DeepSeek-V3.1. Maximum output per response: Gemini 2.5 Flash up to 65,536, GPT OSS 120B up to 32,768, DeepSeek-V3.1 up to 8,192 tokens.

Which can read images, PDFs, audio or video?

Gemini 2.5 Flash accepts text, images, PDFs, audio and video; GPT OSS 120B accepts text; DeepSeek-V3.1 accepts text. Gemini 2.5 Flash handles the widest range of inputs.

Are any of these open source?

GPT OSS 120B and DeepSeek-V3.1 publishes its weights (MIT License) and can be self-hosted; Gemini 2.5 Flash is proprietary.

Which is newer?

DeepSeek-V3.1 is the newest, released Aug 21, 2025. GPT OSS 120B came out Aug 5, 2025; Gemini 2.5 Flash came out Jun 17, 2025. Knowledge cutoff: Gemini 2.5 Flash 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 Oct 4, 2026.

05 — Keep comparing

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