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Comparison · 2 models · Updated Oct 4, 2026

Gemini 2.5 Flash vs o3-mini

Gemini 2.5 Flash comes out ahead, 68 to 52 on our weighted score, and it is the cheaper option too.

  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

    o3-mini

    Released Jan 31, 2025Deprecated

    52/100
    • ECI140.3
    • Price$1.10 / $4.40
    • Context200K
    Full specs Remove o3-mini

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Gemini 2.5 Flash is our pick

Gemini 2.5 Flash is the better all-round choice, scoring 68/100 against o3-mini (52). It leads on price, inputs & features and context window. 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 · o3-mini 140.3
  • Lowest priceGemini 2.5 FlashGemini 2.5 Flash $0.85 · o3-mini $1.93 per 1M tokens (3:1 blend)
  • Longest contextGemini 2.5 FlashGemini 2.5 Flash 1,048,576 · o3-mini 200,000 tokens
  • Widest inputsGemini 2.5 FlashGemini 2.5 Flash: Text, Images, PDFs, Audio, Video · o3-mini: Text
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGemini 2.5 Flasho3-mini
CapabilityCapabilities Index (ECI)50%6766
Price25%5336
Inputs & features15%10045
Context window10%6132
Overall100%68/10052/100
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 o3-mini specifications side by side
SpecificationGemini 2.5 FlashGoogleo3-miniOpenAI
Capability
Capabilities Index (ECI)140.8 (best)140.3
ECI rank#97 of 148 (best)#98 of 148
GPQA DiamondGraduate-level science questions—77.0%
FrontierMath Tiers 1–3Research-level mathematics—18.6%
OTIS Mock AIME 2024–2025Competition mathematics—76.9%
SimpleQA VerifiedShort factual questions—15.3%
Price per million tokens
Input$0.30 (best)$1.10
Output$2.50 (best)$4.40
Cached input$0.03 (best)$0.55
Blended (3:1)$0.85 (best)$1.93
Long-context rateSame rateSame rate
Price sourceOfficial Google APIOfficial OpenAI API
Limits
Context window1,048,576 tokens (best)200,000 tokens
Max output65,536 tokens100,000 tokens (best)
Inputs and features
TextYesYes
ImagesYesNo
PDFsYesNo
AudioYesNo
VideoYesNo
ReasoningYesYeslow · medium · high
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgemini-2.5-flasho3-mini
API providers22 (best)15
ReleasedJun 17, 2025Jan 31, 2025
Knowledge cutoffJan 2025May 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.

  • Gemini 2.5 Flash$8.00
  • o3-mini$19.80
04 — Questions

Which should you choose?

Which is better: Gemini 2.5 Flash or o3-mini?

Gemini 2.5 Flash is the better all-round choice, scoring 68/100 against o3-mini (52). It leads on price, inputs & features and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Gemini 2.5 Flash or o3-mini?

Gemini 2.5 Flash is cheaper at $0.30 input / $2.50 output per million tokens (official Google API price). o3-mini costs $1.10 input / $4.40 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $0.85 per million tokens for Gemini 2.5 Flash versus $1.93 for o3-mini (2.3× 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) and o3-mini 140.3 (#98 of 148). The confidence ranges of the top two overlap (138.5–142.3 vs 137.4–141.9), so treat the gap as small.

Which is better for coding?

There are no published SWE-bench Verified results for Gemini 2.5 Flash and o3-mini 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. Both 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 200,000 for o3-mini. Maximum output per response: Gemini 2.5 Flash up to 65,536, o3-mini up to 100,000 tokens.

Which can read images, PDFs, audio or video?

Gemini 2.5 Flash accepts text, images, PDFs, audio and video; o3-mini accepts text. Gemini 2.5 Flash handles the widest range of inputs.

Are any of these open source?

No. Gemini 2.5 Flash and o3-mini are proprietary and only available through APIs and apps.

Which is newer?

Gemini 2.5 Flash is the newest, released Jun 17, 2025. o3-mini came out Jan 31, 2025. Knowledge cutoff: Gemini 2.5 Flash Jan 2025, o3-mini May 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 Oct 4, 2026.

05 — Keep comparing

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