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Mercury 2 vs o3 Mini

Updated October 21, 2026. 28 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Mercury 2 Replace o3 Mini
Mercury 2Inception
Coding
0.0
Overall
10.8
Output $/M
$0.75
18
o3 MiniOpenAI
Coding
52.1
Overall
12.5
Output $/M
$4.40
10
vs boards won of 28 shared

Decision reading

Pick o3 Mini for coding: it scores 52.1 on the Vibe Coding Index against 0.0 for Mercury 2.

Pick Mercury 2 when output tokens cost 5.9x less, or when what matters is Terminal-Bench Hard (Artificial Analysis run) or LMArena Text: coding, where it leads.

Model AMercury 2Inception0.0/1001 independent benchmarkNo cost per solved taskModel Bo3 MiniOpenAI52.1/1002 independent benchmarksNo cost per solved task
Shared results
28
Mercury 2 only
14
o3 Mini only
42
Like-for-like categories
6 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
Mercury 2 0.0 from 1 benchmark, o3 Mini 52.1 from 2 benchmarks.
Widest category
Agentic work, 39.5 points apart on average over 1 shared benchmark.
Widest single gap
τ²-Bench Telecom: Mercury 2 70.8% against o3 Mini 31.3%, 39.5 points apart on a 0 to 100 scale.
Output price
Mercury 2 $0.75 against o3 Mini $4.40 per million output tokens, 5.9x apart.
Context window
Mercury 2 takes 128K tokens, o3 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
CategoryMercury 2Barso3 MiniTies
Coding32
Intelligence01
Agentic work10
Reasoning14
Knowledge30
General103
All shared boards1810
CodingLike-for-likeFour of these boards feed the Vibe Coding Index32
Coding benchmarks for Mercury 2 and o3 Mini
BenchmarkMercury 2o3 MiniLeader
Aider polyglotNot measured60.4%Only o3 Mini measured
SWE-bench VerifiedNot measured42.4%Only o3 Mini measured
SWE-bench LiteNot measured32.3%Only o3 Mini measured
LMArena WebDev1171Not measuredOnly Mercury 2 measured
AA Coding Index31.1Not measuredOnly Mercury 2 measured
LiveCodeBench (Vals AI)Not measured71.5%Only o3 Mini measured
LiveCodeBench (Artificial Analysis run)Not measured73.4%Only o3 Mini measured
SciCode37.7%42.8%o3 Mini
Terminal-Bench Hard (Artificial Analysis run)26.5%6.8%Mercury 2
GSO-BenchNot measured1.3%Only o3 Mini measured
WeirdML43.2%43.7%o3 Mini
CybenchNot measured22.5%Only o3 Mini measured
ALE-Bench785.6Not measuredOnly Mercury 2 measured
LMArena Text: coding13901378Mercury 2
LMArena Text: software and IT13851364Mercury 2
LMArena WebDev: React1160Not measuredOnly Mercury 2 measured
LMArena WebDev: HTML1199Not measuredOnly Mercury 2 measured
Neither model has a result on the other 21 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
Intelligence benchmarks for Mercury 2 and o3 Mini
BenchmarkMercury 2o3 MiniLeader
AA Intelligence Index10.812.5o3 Mini
Epoch Capabilities IndexNot measured140.2Only o3 Mini measured
Agentic workLike-for-likePublic boards, shown as published, kept out of the index10
Agentic work benchmarks for Mercury 2 and o3 Mini
BenchmarkMercury 2o3 MiniLeader
AA Agentic Index1.6Not measuredOnly Mercury 2 measured
τ²-Bench Telecom70.8%31.3%Mercury 2
Neither model has a result on the other 37 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index14
Reasoning benchmarks for Mercury 2 and o3 Mini
BenchmarkMercury 2o3 MiniLeader
GPQA DiamondNot measured75.5%Only o3 Mini measured
GPQA Diamond (Artificial Analysis run)77.0%77.3%o3 Mini
Humanity's Last Exam (Artificial Analysis run)17.1%12.0%Mercury 2
GPQA Diamond (Epoch AI run)Not measured77.0%Only o3 Mini measured
ARC-AGINot measured34.5%Only o3 Mini measured
ARC-AGI-2Not measured3.0%Only o3 Mini measured
SimpleBenchNot measured22.8%Only o3 Mini measured
Chess puzzlesNot measured15.0%Only o3 Mini measured
Mystery game puzzlesNot measured7.0%Only o3 Mini measured
LMArena Text: hard prompts13621365o3 Mini
LMArena Text: expert13581364o3 Mini
LMArena Text: hard prompts in English13741375o3 Mini
Neither model has a result on the other 9 boards here
MathDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared
Math benchmarks for Mercury 2 and o3 Mini
BenchmarkMercury 2o3 MiniLeader
AIMENot measured86.5%Only o3 Mini measured
MATH 500 (Vals AI)Not measured91.8%Only o3 Mini measured
MGSM (Vals AI)Not measured91.3%Only o3 Mini measured
OTIS Mock AIMENot measured76.9%Only o3 Mini measured
FrontierMath, tiers 1 to 3Not measured18.6%Only o3 Mini measured
FrontierMath, tier 4Not measured0.0%Only o3 Mini measured
MATH level 5Not measured96.5%Only o3 Mini measured
LMArena Text: mathNot measured1396Only o3 Mini measured
LMArena Text: mathematical workNot measured1399Only o3 Mini measured
Neither model has a result on the other 4 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index30
Knowledge benchmarks for Mercury 2 and o3 Mini
BenchmarkMercury 2o3 MiniLeader
MMLU ProNot measured78.7%Only o3 Mini measured
LegalBench (Vals AI)Not measured71.5%Only o3 Mini measured
CorpFin (Vals AI)Not measured45.3%Only o3 Mini measured
TaxEval (Vals AI)Not measured69.4%Only o3 Mini measured
MedQA (Vals AI)Not measured94.8%Only o3 Mini measured
MMLU Pro (Artificial Analysis run)Not measured80.2%Only o3 Mini measured
SimpleQA VerifiedNot measured15.3%Only o3 Mini measured
LMArena Text: science13431339Mercury 2
LMArena Text: medicine and healthcare13631330Mercury 2
LMArena Text: legal and governmentNot measured1328Only o3 Mini measured
LMArena Text: business and finance13491313Mercury 2
Neither model has a result on the other 6 boards here
Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
Web design benchmarks for Mercury 2 and o3 Mini
BenchmarkMercury 2o3 MiniLeader
Design Arena: websites1036Not measuredOnly Mercury 2 measured
Design Arena: UI components998Not measuredOnly Mercury 2 measured
Design Arena: game dev985Not measuredOnly Mercury 2 measured
Design Arena: data viz1009Not measuredOnly Mercury 2 measured
Design Arena: 3D982Not measuredOnly Mercury 2 measured
Design Arena: all code categories1022Not measuredOnly Mercury 2 measured
Design Arena: SVG998Not measuredOnly Mercury 2 measured
Design Arena: ASCII art990Not measuredOnly Mercury 2 measured
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index103
General benchmarks for Mercury 2 and o3 Mini
BenchmarkMercury 2o3 MiniLeader
IFBench69.8%67.1%Mercury 2
Long context reasoning (AA-LCR)43.7%43.0%Mercury 2
DTBenchNot measured68.8%Only o3 Mini measured
LMCANot measured19.0%Only o3 Mini measured
Fiction.LiveBenchNot measured50.0%Only o3 Mini measured
Creative writing (Lech Mazur)Not measured61.7%Only o3 Mini measured
LMArena Text13541337Mercury 2
LMArena Text: instruction following13281337o3 Mini
LMArena Text: creative writing12861286Mercury 2
LMArena Text: English13781351Mercury 2
LMArena Text: non-English13301319Mercury 2
LMArena Text: Chinese14141379Mercury 2
LMArena Text: GermanNot measured1303Only o3 Mini measured
LMArena Text: JapaneseNot measured1286Only o3 Mini measured
LMArena Text: KoreanNot measured1313Only o3 Mini measured
LMArena Text: FrenchNot measured1334Only o3 Mini measured
LMArena Text: SpanishNot measured1321Only o3 Mini measured
LMArena Text: Russian13041304Mercury 2
LMArena Text: PolishNot measured1294Only o3 Mini measured
LMArena Text: multi-turn13571320Mercury 2
LMArena Text: longer queries13291343o3 Mini
LMArena Text: writing and language13001313o3 Mini
LMArena Text: entertainment and media13141283Mercury 2
Neither model has a result on the other 23 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Mercury 2 and o3 Mini
BenchmarkMercury 2o3 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

Mercury 2$0.0006Fits in one request
o3 Mini$0.0033Fits in one request

Mercury 2 costs less

Repository review

50K input + 3K output tokens

Mercury 2$0.015Fits in one request
o3 Mini$0.068Fits in one request

Mercury 2 costs less

Agent loop

200K input + 10K output tokens

Mercury 2$0.058Exceeds the context window
o3 Mini$0.264Exceeds the context window

Mercury 2 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 Mercury 2 and o3 Mini
SpecificationInception Mercury 2OpenAI o3 Mini
MakerInceptionOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedMarch 4, 2026January 31, 2025
Context window128K200K
Input $/Mtok$0.25$1.10
Output $/Mtok$0.75$4.40
Coding index0.052.1
Independent measurements behind it12
Cost per solved taskNot computableNot computable
SourceOpenRouter listingOpenRouter listing

Questions

Is Mercury 2 better than o3 Mini for coding?

Pick o3 Mini for coding: it scores 52.1 on the Vibe Coding Index against 0.0 for Mercury 2. Pick Mercury 2 when output tokens cost 5.9x less, or when what matters is Terminal-Bench Hard (Artificial Analysis run) or LMArena Text: coding, where it leads.

Which is cheaper, Mercury 2 or o3 Mini?

Mercury 2 costs $0.25 per million input tokens and $0.75 per million output tokens; o3 Mini costs $1.10 and $4.40. Cost per solved task is known for neither of them.

Which has the bigger context window, Mercury 2 or o3 Mini?

o3 Mini, with 200K tokens against 128K.

How many benchmarks is the Mercury 2 vs o3 Mini comparison based on?

28 benchmarks have a result for both models as of October 21, 2026. Mercury 2's coding index rests on 1 independent benchmark and o3 Mini's on 2. Where only one model has a result, the page says so instead of naming a winner.

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