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Gemini 2.5 Flash vs o4 Mini

Updated October 21, 2026. 65 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Gemini 2.5 Flash Replace o4 Mini
Gemini 2.5 FlashGoogle
Coding
28.7
Overall
15.5
Output $/M
$2.50
51
o4 MiniOpenAI
Coding
68.6
Overall
16.7
Output $/M
$4.40
13
vs boards won of 65 shared, 1 tied

Decision reading

Pick o4 Mini for coding: it scores 68.6 on the Vibe Coding Index against 28.7 for Gemini 2.5 Flash.

Pick Gemini 2.5 Flash when output tokens cost 1.8x less, or when the context window is larger, 1.05M against 200K tokens.

Model AGemini 2.5 FlashGoogle28.7/1001 independent benchmark$0.466 per solved taskModel Bo4 MiniOpenAI68.6/1002 independent benchmarksNo cost per solved task
Shared results
65
Gemini 2.5 Flash only
4
o4 Mini only
29
Like-for-like categories
8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

At a glance

Coding index
Gemini 2.5 Flash 28.7 from 1 benchmark, o4 Mini 68.6 from 2 benchmarks.
Widest category
Agentic work, 24.0 points apart on average over 1 shared benchmark.
Widest single gap
SWE-bench Verified: Gemini 2.5 Flash 28.7% against o4 Mini 64.6%, 35.9 points apart on a 0 to 100 scale.
Output price
Gemini 2.5 Flash $2.50 against o4 Mini $4.40 per million output tokens, 1.8x apart.
Context window
Gemini 2.5 Flash takes 1.05M tokens, o4 Mini 200K.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
CategoryGemini 2.5 FlashBarso4 MiniTies
Coding23
Intelligence02
Agentic work01
Reasoning73
Math22
Knowledge501 tie
Web design60
General292
All shared boards51131 tie
CodingLike-for-likeFour of these boards feed the Vibe Coding Index23
Coding benchmarks for Gemini 2.5 Flash and o4 Mini
BenchmarkGemini 2.5 Flasho4 MiniLeader
Aider polyglotNot measured72.0%Only o4 Mini measured
SWE-bench Verified28.7%64.6%o4 Mini
SWE-bench MultimodalNot measured33.9%Only o4 Mini measured
LiveCodeBench (Vals AI)Not measured82.2%Only o4 Mini measured
LiveCodeBench (Artificial Analysis run)69.5%85.9%o4 Mini
Terminal-Bench Hard (Artificial Analysis run)13.6%15.2%o4 Mini
Terminal-Bench17.1%Not measuredOnly Gemini 2.5 Flash measured
GSO-BenchNot measured3.6%Only o4 Mini measured
WeirdMLNot measured52.6%Only o4 Mini measured
LMArena Text: coding14231368Gemini 2.5 Flash
LMArena Text: software and IT14251367Gemini 2.5 Flash
Neither model has a result on the other 27 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Gemini 2.5 Flash and o4 Mini
BenchmarkGemini 2.5 Flasho4 MiniLeader
AA Intelligence Index15.516.7o4 Mini
Epoch Capabilities Index142.9145.5o4 Mini
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
Agentic work benchmarks for Gemini 2.5 Flash and o4 Mini
BenchmarkGemini 2.5 Flasho4 MiniLeader
τ²-Bench Telecom31.6%55.6%o4 Mini
METR time horizonsNot measured63.9%Only o4 Mini measured
BALROG33.5%Not measuredOnly Gemini 2.5 Flash measured
Vending-Bench 2$549Not measuredOnly Gemini 2.5 Flash measured
Neither model has a result on the other 35 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index73
Reasoning benchmarks for Gemini 2.5 Flash and o4 Mini
BenchmarkGemini 2.5 Flasho4 MiniLeader
GPQA DiamondNot measured74.5%Only o4 Mini measured
MMMU Pro (Vals AI)Not measured79.7%Only o4 Mini measured
GPQA Diamond (Artificial Analysis run)79.0%78.4%Gemini 2.5 Flash
Humanity's Last Exam (Artificial Analysis run)12.1%16.5%o4 Mini
GPQA Diamond (Epoch AI run)Not measured79.6%Only o4 Mini measured
ARC-AGI33.3%58.7%o4 Mini
ARC-AGI-22.5%6.1%o4 Mini
SimpleBench41.2%38.7%Gemini 2.5 Flash
Chess puzzlesNot measured22.0%Only o4 Mini measured
Mystery game puzzlesNot measured5.0%Only o4 Mini measured
VPCTNot measured57.5%Only o4 Mini measured
LMArena Text: hard prompts14221351Gemini 2.5 Flash
LMArena Text: expert14261343Gemini 2.5 Flash
LMArena Text: hard prompts in English14201366Gemini 2.5 Flash
LMArena Vision: diagrams12451197Gemini 2.5 Flash
LMArena Vision: homework12441234Gemini 2.5 Flash
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index22
Math benchmarks for Gemini 2.5 Flash and o4 Mini
BenchmarkGemini 2.5 Flasho4 MiniLeader
AIMENot measured83.7%Only o4 Mini measured
MATH 500 (Vals AI)Not measured94.2%Only o4 Mini measured
MGSM (Vals AI)Not measured93.4%Only o4 Mini measured
AA Math Index73.390.7o4 Mini
AIME 2025 (Artificial Analysis run)73.3%90.7%o4 Mini
OTIS Mock AIMENot measured81.7%Only o4 Mini measured
FrontierMath, tiers 1 to 3Not measured36.1%Only o4 Mini measured
FrontierMath, tier 4Not measured4.9%Only o4 Mini measured
MATH level 5Not measured97.8%Only o4 Mini measured
LMArena Text: math14111389Gemini 2.5 Flash
LMArena Text: mathematical work14221379Gemini 2.5 Flash
Neither model has a result on the other 2 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index50
Knowledge benchmarks for Gemini 2.5 Flash and o4 Mini
BenchmarkGemini 2.5 Flasho4 MiniLeader
MMLU ProNot measured80.6%Only o4 Mini measured
LegalBench (Vals AI)Not measured79.2%Only o4 Mini measured
CorpFin (Vals AI)Not measured59.0%Only o4 Mini measured
TaxEval (Vals AI)Not measured74.8%Only o4 Mini measured
MortgageTax (Vals AI)Not measured64.8%Only o4 Mini measured
MedQA (Vals AI)Not measured96.0%Only o4 Mini measured
MedCode (Vals AI)40.4%33.8%Gemini 2.5 Flash
MMLU Pro (Artificial Analysis run)83.2%83.2%Tie
SimpleQA VerifiedNot measured19.6%Only o4 Mini measured
GeoBenchNot measured64.0%Only o4 Mini measured
LMArena Text: science14331354Gemini 2.5 Flash
LMArena Text: medicine and healthcare14281361Gemini 2.5 Flash
LMArena Text: legal and government14301350Gemini 2.5 Flash
LMArena Text: business and finance14041325Gemini 2.5 Flash
Neither model has a result on the other 3 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index60
Web design benchmarks for Gemini 2.5 Flash and o4 Mini
BenchmarkGemini 2.5 Flasho4 MiniLeader
Design Arena: websites1074985Gemini 2.5 Flash
Design Arena: UI components1005983Gemini 2.5 Flash
Design Arena: game dev10051004Gemini 2.5 Flash
Design Arena: data viz1060990Gemini 2.5 Flash
Design Arena: 3D1021854Gemini 2.5 Flash
Design Arena: all code categories1059977Gemini 2.5 Flash
Design Arena: SVG1018Not measuredOnly Gemini 2.5 Flash measured
Neither model has a result on the other 2 boards here
GeneralLike-for-likePublic boards, shown as published, kept out of the index292
General benchmarks for Gemini 2.5 Flash and o4 Mini
BenchmarkGemini 2.5 Flasho4 MiniLeader
SAGE (Vals AI)44.8%41.1%Gemini 2.5 Flash
MedScribe (Vals AI)83.0%69.1%Gemini 2.5 Flash
IFBench50.3%68.7%o4 Mini
Long context reasoning (AA-LCR)65.3%61.0%Gemini 2.5 Flash
DTBench76.5%77.6%o4 Mini
LMCA27.5%26.5%Gemini 2.5 Flash
Fiction.LiveBenchNot measured77.8%Only o4 Mini measured
Creative writing (Lech Mazur)Not measured75.0%Only o4 Mini measured
LMArena Text14171353Gemini 2.5 Flash
LMArena Text: instruction following14051320Gemini 2.5 Flash
LMArena Text: creative writing14001294Gemini 2.5 Flash
LMArena Vision12351194Gemini 2.5 Flash
LMArena Text: English14181367Gemini 2.5 Flash
LMArena Text: non-English14091337Gemini 2.5 Flash
LMArena Text: Chinese14491354Gemini 2.5 Flash
LMArena Text: German14171336Gemini 2.5 Flash
LMArena Text: Japanese13961308Gemini 2.5 Flash
LMArena Text: Korean13851312Gemini 2.5 Flash
LMArena Text: French14321364Gemini 2.5 Flash
LMArena Text: Spanish14221346Gemini 2.5 Flash
LMArena Text: Russian14151334Gemini 2.5 Flash
LMArena Text: Polish14131358Gemini 2.5 Flash
LMArena Text: multi-turn14081350Gemini 2.5 Flash
LMArena Text: longer queries14191315Gemini 2.5 Flash
LMArena Text: writing and language14051316Gemini 2.5 Flash
LMArena Text: entertainment and media13931308Gemini 2.5 Flash
LMArena Vision: English12391200Gemini 2.5 Flash
LMArena Vision: Chinese12841218Gemini 2.5 Flash
LMArena Vision: reading text12371197Gemini 2.5 Flash
LMArena Vision: humor12251199Gemini 2.5 Flash
LMArena Vision: captioning12771204Gemini 2.5 Flash
LMArena Vision: recognizing things12521218Gemini 2.5 Flash
LMArena Vision: creative writing12411166Gemini 2.5 Flash
Neither model has a result on the other 13 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Gemini 2.5 Flash and o4 Mini
BenchmarkGemini 2.5 Flasho4 MiniLeader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

Gemini 2.5 Flash$0.0015Fits in one request
o4 Mini$0.0033Fits in one request

Gemini 2.5 Flash costs less

Repository review

50K input + 3K output tokens

Gemini 2.5 Flash$0.022Fits in one request
o4 Mini$0.068Fits in one request

Gemini 2.5 Flash costs less

Agent loop

200K input + 10K output tokens

Gemini 2.5 Flash$0.085Fits in one request
o4 Mini$0.264Exceeds the context window

Gemini 2.5 Flash costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of Gemini 2.5 Flash and o4 Mini
SpecificationGoogle Gemini 2.5 FlashOpenAI o4 Mini
MakerGoogleOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedJune 17, 2025April 16, 2025
Context window1.05M200K
Input $/Mtok$0.30$1.10
Output $/Mtok$2.50$4.40
Coding index28.768.6
Independent measurements behind it12
Cost per solved task$0.466Not computable
SourceOpenRouter listingOpenRouter listing

Questions

Is Gemini 2.5 Flash better than o4 Mini for coding?

Pick o4 Mini for coding: it scores 68.6 on the Vibe Coding Index against 28.7 for Gemini 2.5 Flash. Pick Gemini 2.5 Flash when output tokens cost 1.8x less, or when the context window is larger, 1.05M against 200K tokens.

Which is cheaper, Gemini 2.5 Flash or o4 Mini?

Gemini 2.5 Flash costs $0.30 per million input tokens and $2.50 per million output tokens; o4 Mini costs $1.10 and $4.40. Cost per solved task is known for Gemini 2.5 Flash only.

Which has the bigger context window, Gemini 2.5 Flash or o4 Mini?

Gemini 2.5 Flash, with 1.05M tokens against 200K.

How many benchmarks is the Gemini 2.5 Flash vs o4 Mini comparison based on?

65 benchmarks have a result for both models as of October 21, 2026. Gemini 2.5 Flash's coding index rests on 1 independent benchmark and o4 Mini's on 2. Where only one model has a result, the page says so instead of naming a winner.

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