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Gemini 2.5 Flash vs o3-mini

A complete head-to-head: pricing, context window, benchmarks, modality coverage, and openness, with a programmatic verdict synthesized from the underlying data.

Updated

Gemini 2.5 Flash specs · o3-mini specs
Verdict by category
  • PriceGemini 2.5 Flash

    Gemini 2.5 Flash is roughly 14.7× cheaper on output tokens ($0.30 vs $4.40 per 1M).

  • Context windowGemini 2.5 Flash

    Gemini 2.5 Flash accepts 1.0M tokens vs 200K, 5.2× the room for long documents and codebases.

  • BenchmarksTie

    No directly comparable public benchmarks are available for both models, check the spec sheets for individual scores.

  • ModalitiesGemini 2.5 Flash

    Gemini 2.5 Flash supports 3 modalities (text, vision, audio) vs 1 for o3-mini.

  • OpennessTie

    Both are closed-weight, API-only.

On balance Gemini 2.5 Flash edges ahead, winning 3 of 5 categories against o3-mini's 0. Gemini 2.5 Flash is roughly 14.7× cheaper on output tokens ($0.30 vs $4.40 per 1M). Gemini 2.5 Flash accepts 1.0M tokens vs 200K, 5.2× the room for long documents and codebases.

No directly comparable public benchmarks are available for both models, check the spec sheets for individual scores. They differ in modality coverage, Gemini 2.5 Flash handles text, vision, audio while o3-mini handles text, which can be the deciding factor before you even look at benchmarks. Both are closed-weight, API-only.

Gemini 2.5 Flash is the newer of the two, released 2 months after o3-mini, which usually means a more recent knowledge cutoff and updated safety post-training. Gemini 2.5 Flash is usually picked for rag and long context workloads, while o3-mini sees more deployments in reasoning and math. If pricing matters more than every last benchmark point, run the numbers in the calculator below before committing.

Side-by-side specs

SpecGemini 2.5 Flasho3-mini
ProviderGoogleOpenAI
ReleasedApr 2025Jan 2025
Modalitiestext, vision, audiotext
Context window1.0M tokens200K tokens
Max output,,
Input · 1M$0.075 / 1M tokens$1.10 / 1M tokens
Output · 1M$0.30 / 1M tokens$4.40 / 1M tokens
Knowledge cutoff2025-012023-10
Open weightsNoNo
API availableYesYes

Pricing at scale

What you'd actually pay at typical workloads. Numbers come from each model's published per-million-token rates.

  • Light usage, 100k in / 50k out per day$0.675 vs $9.90
  • Heavy usage, 1M in / 500k out per day$6.75 vs $99.00
  • RAG workload, 5M in / 200k out per day$13.05 vs $191

Light usage, 100k in / 50k out per day: $0.675 vs $9.90 per month, model A comes out ahead. Heavy usage, 1M in / 500k out per day: $6.75 vs $99.00 per month, model A comes out ahead. RAG workload, 5M in / 200k out per day: $13.05 vs $191 per month, model A comes out ahead.

Price calculator

Estimated spend for the listed models at your usage. Numbers are derived from each model's published per-million-token rates.

  • Gemini 2.5 Flash$0.022
  • o3-mini$0.330

Benchmarks compared

Only sourced numbers. Where a benchmark is missing for one model we show the available value rather than fabricating the other.

Gemini 2.5 Flasho3-mini
  • GPQA,79.7
Pick Gemini 2.5 Flash if

Gemini 2.5 Flash fits when…

  • Cheap and fast
  • Long context
  • Solid vision
  • Cost-sensitive workloads, 14.7× cheaper than o3-mini on output tokens.
  • Long-context tasks, handles 1.0M tokens vs 200K for o3-mini.
Pick o3-mini if

o3-mini fits when…

  • Reasoning at mid-tier cost
  • Fast for a thinking model
Don't want either?

Consider Gemini 3 Pro

Google's late-2025 flagship, set new benchmarks on long-context, vision, and reasoning at competitive pricing.

See Gemini 3 Pro specsGemini 2.5 Flash vs Gemini 3 Proo3-mini vs Gemini 3 Pro

Frequently asked

  • Is Gemini 2.5 Flash or o3-mini cheaper?
    Gemini 2.5 Flash is cheaper at $0.30 / 1M tokens per million output tokens, vs $4.40 / 1M tokens for o3-mini.
  • Which has the larger context window?
    Gemini 2.5 Flash accepts 1.0M tokens vs 200K for o3-mini.
  • Is Gemini 2.5 Flash or o3-mini better for coding?
    Both Gemini 2.5 Flash and o3-mini are competitive on coding benchmarks. See each model's individual spec page for HumanEval and SWE-bench scores where published. For an opinionated pick, consult our Best LLM for Coding ranking.
  • Are either of these models open source?
    Neither model ships open weights, both are accessible only via their respective providers' APIs.
  • When were Gemini 2.5 Flash and o3-mini released?
    Gemini 2.5 Flash was released by Google on 2025-04-09. o3-mini was released by OpenAI on 2025-01-31.
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