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Gemini 2.5 Flash vs GPT-5

Updated October 21, 2026. 68 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 GPT-5
Gemini 2.5 FlashGoogle
Coding
28.7
Overall
15.5
Output $/M
$2.50
31
GPT-5OpenAI
Coding
72.2
Overall
23.0
Output $/M
$10.00
37
vs boards won of 68 shared

Decision reading

Pick GPT-5 for coding: it scores 72.2 on the Vibe Coding Index against 28.7 for Gemini 2.5 Flash.

Pick Gemini 2.5 Flash when output tokens cost 4.0x less, or when the context window is larger, 1.05M against 400K tokens.

Model AGemini 2.5 FlashGoogle28.7/1001 independent benchmark$0.466 per solved taskModel BGPT-5OpenAI72.2/1003 independent benchmarks$0.39 per solved task
Shared results
68
Gemini 2.5 Flash only
1
GPT-5 only
41
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, GPT-5 72.2 from 3 benchmarks.
Widest category
Agentic work, 27.8 points apart on average over 2 shared benchmarks.
Widest single gap
τ²-Bench Telecom: Gemini 2.5 Flash 31.6% against GPT-5 86.5%, 55.0 points apart on a 0 to 100 scale.
Output price
Gemini 2.5 Flash $2.50 against GPT-5 $10.00 per million output tokens, 4.0x apart.
Context window
Gemini 2.5 Flash takes 1.05M tokens, GPT-5 400K.

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 FlashBarsGPT-5Ties
Coding15
Intelligence02
Agentic work11
Reasoning37
Math22
Knowledge33
Web design07
General2110
All shared boards3137
CodingLike-for-likeFour of these boards feed the Vibe Coding Index15
Coding benchmarks for Gemini 2.5 Flash and GPT-5
BenchmarkGemini 2.5 FlashGPT-5Leader
Aider polyglotNot measured88.0%Only GPT-5 measured
SWE-bench Verified28.7%74.4%GPT-5
LMArena WebDevNot measured1418Only GPT-5 measured
AA Coding IndexNot measured37.8Only GPT-5 measured
LiveCodeBench (Vals AI)Not measured85.9%Only GPT-5 measured
SWE-bench Verified (Vals AI)Not measured69.0%Only GPT-5 measured
Vibe Code Bench (Vals AI)Not measured20.1%Only GPT-5 measured
LiveCodeBench (Artificial Analysis run)69.5%84.6%GPT-5
Terminal-Bench Hard (Artificial Analysis run)13.6%37.9%GPT-5
Terminal-Bench17.1%49.6%GPT-5
GSO-BenchNot measured6.9%Only GPT-5 measured
WeirdMLNot measured60.7%Only GPT-5 measured
ALE-BenchNot measured807.6Only GPT-5 measured
LMArena Text: coding14231436GPT-5
LMArena Text: software and IT14251420Gemini 2.5 Flash
LMArena WebDev: HTMLNot measured1427Only GPT-5 measured
Neither model has a result on the other 22 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Gemini 2.5 Flash and GPT-5
BenchmarkGemini 2.5 FlashGPT-5Leader
AA Intelligence Index15.523.0GPT-5
Epoch Capabilities Index142.9150.0GPT-5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index11
Agentic work benchmarks for Gemini 2.5 Flash and GPT-5
BenchmarkGemini 2.5 FlashGPT-5Leader
τ²-Bench Telecom31.6%86.5%GPT-5
METR time horizonsNot measured69.6%Only GPT-5 measured
Remote Labor IndexNot measured1.7%Only GPT-5 measured
GDPvalNot measured34.8%Only GPT-5 measured
BALROG33.5%32.8%Gemini 2.5 Flash
DeepResearch BenchNot measured49.6%Only GPT-5 measured
Vending-Bench 2$549Not measuredOnly Gemini 2.5 Flash measured
Neither model has a result on the other 32 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index37
Reasoning benchmarks for Gemini 2.5 Flash and GPT-5
BenchmarkGemini 2.5 FlashGPT-5Leader
GPQA DiamondNot measured85.6%Only GPT-5 measured
MMMU Pro (Vals AI)Not measured81.5%Only GPT-5 measured
GPQA Diamond (Artificial Analysis run)79.0%85.4%GPT-5
Humanity's Last Exam (Artificial Analysis run)12.1%28.5%GPT-5
GPQA Diamond (Epoch AI run)Not measured86.2%Only GPT-5 measured
ARC-AGI33.3%65.7%GPT-5
ARC-AGI-22.5%9.9%GPT-5
SimpleBench41.2%56.7%GPT-5
Chess puzzlesNot measured36.0%Only GPT-5 measured
Mystery game puzzlesNot measured23.0%Only GPT-5 measured
EBR-benchNot measured12.7%Only GPT-5 measured
VPCTNot measured66.0%Only GPT-5 measured
LMArena Text: hard prompts14221415Gemini 2.5 Flash
LMArena Text: expert14261419Gemini 2.5 Flash
LMArena Text: hard prompts in English14201419Gemini 2.5 Flash
LMArena Vision: diagrams12451252GPT-5
LMArena Vision: homework12441278GPT-5
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index22
Math benchmarks for Gemini 2.5 Flash and GPT-5
BenchmarkGemini 2.5 FlashGPT-5Leader
AIMENot measured93.4%Only GPT-5 measured
MATH 500 (Vals AI)Not measured96.0%Only GPT-5 measured
MGSM (Vals AI)Not measured92.8%Only GPT-5 measured
AA Math Index73.394.3GPT-5
AIME 2025 (Artificial Analysis run)73.3%94.3%GPT-5
OTIS Mock AIMENot measured91.4%Only GPT-5 measured
FrontierMath, tiers 1 to 3Not measured55.4%Only GPT-5 measured
FrontierMath, tier 4Not measured22.0%Only GPT-5 measured
ProofBenchNot measured18.0%Only GPT-5 measured
MATH level 5Not measured98.1%Only GPT-5 measured
LMArena Text: math14111407Gemini 2.5 Flash
LMArena Text: mathematical work14221405Gemini 2.5 Flash
Neither model has a result on the other 1 board here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index33
Knowledge benchmarks for Gemini 2.5 Flash and GPT-5
BenchmarkGemini 2.5 FlashGPT-5Leader
MMLU ProNot measured86.5%Only GPT-5 measured
LegalBench (Vals AI)Not measured86.0%Only GPT-5 measured
CaseLaw (Vals AI)Not measured66.5%Only GPT-5 measured
CorpFin (Vals AI)Not measured61.1%Only GPT-5 measured
TaxEval (Vals AI)Not measured73.4%Only GPT-5 measured
MortgageTax (Vals AI)Not measured65.5%Only GPT-5 measured
MedQA (Vals AI)Not measured96.3%Only GPT-5 measured
MedCode (Vals AI)40.4%49.6%GPT-5
MMLU Pro (Artificial Analysis run)83.2%87.1%GPT-5
SimpleQA VerifiedNot measured50.1%Only GPT-5 measured
GeoBenchNot measured81.0%Only GPT-5 measured
LMArena Text: science14331416Gemini 2.5 Flash
LMArena Text: medicine and healthcare14281413Gemini 2.5 Flash
LMArena Text: legal and government14301431GPT-5
LMArena Text: business and finance14041400Gemini 2.5 Flash
Neither model has a result on the other 2 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index07
Web design benchmarks for Gemini 2.5 Flash and GPT-5
BenchmarkGemini 2.5 FlashGPT-5Leader
Design Arena: websites10741185GPT-5
Design Arena: UI components10051179GPT-5
Design Arena: game dev10051185GPT-5
Design Arena: data viz10601221GPT-5
Design Arena: 3D10211056GPT-5
Design Arena: all code categories10591168GPT-5
Design Arena: SVG10181188GPT-5
Design Arena: ASCII artNot measured1140Only GPT-5 measured
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index2110
General benchmarks for Gemini 2.5 Flash and GPT-5
BenchmarkGemini 2.5 FlashGPT-5Leader
SAGE (Vals AI)44.8%43.7%Gemini 2.5 Flash
MedScribe (Vals AI)83.0%83.7%GPT-5
IFBench50.3%73.1%GPT-5
Long context reasoning (AA-LCR)65.3%78.2%GPT-5
DTBench76.5%90.7%GPT-5
LMCA27.5%40.0%GPT-5
Fiction.LiveBenchNot measured97.2%Only GPT-5 measured
Creative writing (Lech Mazur)Not measured86.0%Only GPT-5 measured
LMArena Text14171406Gemini 2.5 Flash
LMArena Text: instruction following14051388Gemini 2.5 Flash
LMArena Text: creative writing14001365Gemini 2.5 Flash
LMArena Vision12351232Gemini 2.5 Flash
LMArena Text: English14181409Gemini 2.5 Flash
LMArena Text: non-English14091397Gemini 2.5 Flash
LMArena Text: Chinese14491422Gemini 2.5 Flash
LMArena Text: German14171416Gemini 2.5 Flash
LMArena Text: Japanese13961409GPT-5
LMArena Text: Korean13851360Gemini 2.5 Flash
LMArena Text: French14321409Gemini 2.5 Flash
LMArena Text: Spanish14221399Gemini 2.5 Flash
LMArena Text: Russian14151407Gemini 2.5 Flash
LMArena Text: Polish14131431GPT-5
LMArena Text: multi-turn14081426GPT-5
LMArena Text: longer queries14191399Gemini 2.5 Flash
LMArena Text: writing and language14051384Gemini 2.5 Flash
LMArena Text: entertainment and media13931379Gemini 2.5 Flash
LMArena Vision: English12391231Gemini 2.5 Flash
LMArena Vision: Chinese12841267Gemini 2.5 Flash
LMArena Vision: reading text12371246GPT-5
LMArena Vision: humor12251219Gemini 2.5 Flash
LMArena Vision: captioning12771212Gemini 2.5 Flash
LMArena Vision: recognizing things12521263GPT-5
LMArena Vision: creative writing12411210Gemini 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 GPT-5
BenchmarkGemini 2.5 FlashGPT-5Leader
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
GPT-5$0.0063Fits 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
GPT-5$0.092Fits 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
GPT-5$0.350Fits in one request

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 GPT-5
SpecificationGoogle Gemini 2.5 FlashOpenAI GPT-5
MakerGoogleOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedJune 17, 2025August 7, 2025
Context window1.05M400K
Input $/Mtok$0.30$1.25
Output $/Mtok$2.50$10.00
Coding index28.772.2
Independent measurements behind it13
Cost per solved task$0.466$0.39
SourceOpenRouter listingOpenRouter listing

Questions

Is Gemini 2.5 Flash better than GPT-5 for coding?

Pick GPT-5 for coding: it scores 72.2 on the Vibe Coding Index against 28.7 for Gemini 2.5 Flash. Pick Gemini 2.5 Flash when output tokens cost 4.0x less, or when the context window is larger, 1.05M against 400K tokens.

Which is cheaper, Gemini 2.5 Flash or GPT-5?

Gemini 2.5 Flash costs $0.30 per million input tokens and $2.50 per million output tokens; GPT-5 costs $1.25 and $10.00. Per solved SWE-bench Verified task, Gemini 2.5 Flash costs $0.466 and GPT-5 $0.39.

Which has the bigger context window, Gemini 2.5 Flash or GPT-5?

Gemini 2.5 Flash, with 1.05M tokens against 400K.

How many benchmarks is the Gemini 2.5 Flash vs GPT-5 comparison based on?

68 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 GPT-5's on 3. Where only one model has a result, the page says so instead of naming a winner.

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