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Comparison · 2 models · Updated Nov 2, 2026

Gemini 2.5 Flash vs Gemini 2.5 Flash Preview 05-20

Too close to call on our weighted score (Gemini 2.5 Flash Preview 05-20 67, Gemini 2.5 Flash 66). The right pick depends on what you value most.

  1. Google

    Gemini 2.5 Flash

    Released Jun 17, 2025

    66/100
    • ECI140.6
    • Price$0.30 / $2.50
    • Context1.05M
    Full specs Remove Gemini 2.5 Flash

  2. 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

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01 — Verdict

Too close to call

It is close. Our weighted score puts them within a point (Gemini 2.5 Flash Preview 05-20 67/100, Gemini 2.5 Flash 66/100), so choose by what matters most for your work: Gemini 2.5 Flash Preview 05-20 for raw capability. 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 · Gemini 2.5 Flash 140.6
  • Lowest priceGemini 2.5 Flash Preview 05-20Gemini 2.5 Flash Preview 05-20 $0.60 · Gemini 2.5 Flash $0.85 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameGemini 2.5 Flash 1,048,576 · Gemini 2.5 Flash Preview 05-20 1,048,576 tokens
  • Widest inputsSame inputsGemini 2.5 Flash: Text, Images, PDFs, Audio, Video · Gemini 2.5 Flash Preview 05-20: Text, Images, PDFs, Audio, Video
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGemini 2.5 FlashGemini 2.5 Flash Preview 05-20
CapabilityCapabilities Index (ECI)50%6566
Price25%5158
Inputs & features15%10090
Context window10%6161
Overall100%66/10067/100
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 Gemini 2.5 Flash Preview 05-20 specifications side by side
SpecificationGemini 2.5 FlashGoogleGemini 2.5 Flash Preview 05-20Google
Capability
Capabilities Index (ECI)140.6141.5 (best)
ECI rank#110 of 165#106 of 165 (best)
OTIS Mock AIME 2024–2025Competition mathematics—70.8%
Price per million tokens
Input$0.30$0.146 (best)
Output$2.50$1.96 (best)
Cached input$0.03—
Blended (3:1)$0.85$0.60 (best)
Long-context rateSame rateSame rate
Price sourceOfficial Google APIMedian of 2 providers
Limits
Context window1,048,576 tokens1,048,576 tokens
Max output65,536 tokens65,536 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesYes
AudioYesYes
VideoYesYes
ReasoningYesYes
Tool callingYesYes
Structured outputYesNo
Availability
WeightsProprietaryProprietary
API model IDgemini-2.5-flash—
API providers32 (best)2
ReleasedJun 17, 2025May 20, 2025
Knowledge cutoffJan 2025Jan 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
  • Gemini 2.5 Flash Preview 05-20$5.39
04 — Questions

Which should you choose?

Which is better: Gemini 2.5 Flash or Gemini 2.5 Flash Preview 05-20?

It is close. Our weighted score puts them within a point (Gemini 2.5 Flash Preview 05-20 67/100, Gemini 2.5 Flash 66/100), so choose by what matters most for your work: Gemini 2.5 Flash Preview 05-20 for raw capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Gemini 2.5 Flash or Gemini 2.5 Flash Preview 05-20?

Gemini 2.5 Flash Preview 05-20 is cheaper at $0.146 input / $1.96 output per million tokens (median across 2 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 $0.60 per million tokens for Gemini 2.5 Flash Preview 05-20 versus $0.85 for Gemini 2.5 Flash (1.4× 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 Gemini 2.5 Flash 140.6 (#110 of 165). The confidence ranges of the top two overlap (139.3–142.9 vs 138.4–142.1), 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 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 and Gemini 2.5 Flash Preview 05-20 share the same 1,048,576-token context window. Maximum output per response: Gemini 2.5 Flash up to 65,536, Gemini 2.5 Flash Preview 05-20 up to 65,536 tokens.

Which can read images, PDFs, audio or video?

Gemini 2.5 Flash accepts text, images, PDFs, audio and video; Gemini 2.5 Flash Preview 05-20 accepts text, images, PDFs, audio and video. They handle the same number of input types.

Are any of these open source?

No. Gemini 2.5 Flash and Gemini 2.5 Flash Preview 05-20 are proprietary and only available through APIs and apps.

Which is newer?

Gemini 2.5 Flash is the newest, released Jun 17, 2025. Gemini 2.5 Flash Preview 05-20 came out May 20, 2025. Knowledge cutoff: Gemini 2.5 Flash Jan 2025, 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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