Claude Sonnet 4.5 vs Gemma 4 31B

Updated October 21, 2026. 42 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Claude Sonnet 4.5 Replace Gemma 4 31B

Claude Sonnet 4.5Anthropic

Coding: 59.1
Overall: 20.7
Output $/M: $15.00

Gemma 4 31BGoogle

Coding: 38.3
Overall: 14.7
Output $/M: $0.40

vs boards won of 42 shared

Decision reading

Pick Claude Sonnet 4.5 for coding: it scores 59.1 on the Vibe Coding Index against 38.3 for Gemma 4 31B.

Pick Gemma 4 31B when output tokens cost 37.5x less, or when what matters is WeirdML or LMArena Text: math, where it leads.

Model AClaude Sonnet 4.5Anthropic59.1/1002 independent benchmarks$1.16 per solved task Model BGemma 4 31BGoogle38.3/1002 independent benchmarksNo cost per solved task

425026

Shared results: 42
Claude Sonnet 4.5 only: 50
Gemma 4 31B only: 26
Like-for-like categories: 7 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.

Coding
Vibe Coding Index, four public coding benchmarks
Claude Sonnet 4.5
Claude Sonnet 4.5 scores 59.1 against 38.3.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
Claude Sonnet 4.5
Claude Sonnet 4.5 leads, 20.7 against 14.7.
Same board, both measured
Agentic work
AA Agentic Index
Claude Sonnet 4.5
Claude Sonnet 4.5 leads, 15.8 against 4.2.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only Claude Sonnet 4.5 has a GPQA Diamond result, 81.6%.
Directional only
Math
AIME
No call
Only Claude Sonnet 4.5 has a AIME result, 88.2%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Sonnet 4.5 has a MMLU Pro result, 87.4%.
Directional only
Web design
Design Arena: websites
No call
Only Claude Sonnet 4.5 has a Design Arena: websites result, 1190.
Directional only
Long documents
Listed context window
Claude Sonnet 4.5
Claude Sonnet 4.5 takes 1M tokens against 262K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemma 4 31B
Claude Sonnet 4.5 $0.011, Gemma 4 31B $0.0004 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Claude Sonnet 4.5 has the number, $1.16.
Directional only

At a glance

Coding index: Claude Sonnet 4.5 59.1 from 2 benchmarks, Gemma 4 31B 38.3 from 2 benchmarks.
Widest category: Agentic work, 11.6 points apart on average over 1 shared benchmark.
Widest single gap: SimpleQA Verified: Claude Sonnet 4.5 30.7% against Gemma 4 31B 10.4%, 20.3 points apart on a 0 to 100 scale.
Output price: Claude Sonnet 4.5 $15.00 against Gemma 4 31B $0.40 per million output tokens, 37.5x apart.
Context window: Claude Sonnet 4.5 takes 1M tokens, Gemma 4 31B 262K.

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
Category	Claude Sonnet 4.5	Gemma 4 31B
Coding	6	1
Intelligence	2	0
Agentic work	1	0
Reasoning	4	0
Math	1	2
Knowledge	5	2
General	10	8
All shared boards	29	13

CodingLike-for-likeFour of these boards feed the Vibe Coding Index61

Coding benchmarks for Claude Sonnet 4.5 and Gemma 4 31B
Benchmark	Claude Sonnet 4.5	Gemma 4 31B	Leader
SWE-bench Verified	74.8%	Not measured	Only Claude Sonnet 4.5 measured
SWE-bench Multilingual	67.0%	Not measured	Only Claude Sonnet 4.5 measured
LiveBench coding	Not measured	49.0%	Only Gemma 4 31B measured
LMArena WebDev	1394	1367	Claude Sonnet 4.5
AA Coding Index	52.1	43.4	Claude Sonnet 4.5
LiveCodeBench (Vals AI)	73.0%	Not measured	Only Claude Sonnet 4.5 measured
SWE-bench Verified (Vals AI)	70.0%	Not measured	Only Claude Sonnet 4.5 measured
Vibe Code Bench (Vals AI)	22.6%	Not measured	Only Claude Sonnet 4.5 measured
SciCode	Not measured	45.5%	Only Gemma 4 31B measured
Terminal-Bench Hard (Artificial Analysis run)	Not measured	36.4%	Only Gemma 4 31B measured
Terminal-Bench	46.5%	Not measured	Only Claude Sonnet 4.5 measured
GSO-Bench	14.7%	Not measured	Only Claude Sonnet 4.5 measured
WeirdML	47.7%	52.3%	Gemma 4 31B
Cybench	60.0%	Not measured	Only Claude Sonnet 4.5 measured
ALE-Bench	Not measured	925.5	Only Gemma 4 31B measured
LMArena Text: coding	1488	1459	Claude Sonnet 4.5
LMArena Text: software and IT	1473	1463	Claude Sonnet 4.5
LMArena WebDev: React	1386	1359	Claude Sonnet 4.5
LMArena WebDev: HTML	1399	1380	Claude Sonnet 4.5
Neither model has a result on the other 19 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20

Intelligence benchmarks for Claude Sonnet 4.5 and Gemma 4 31B
Benchmark	Claude Sonnet 4.5	Gemma 4 31B	Leader
AA Intelligence Index	20.7	14.7	Claude Sonnet 4.5
Epoch Capabilities Index	146.7	143.0	Claude Sonnet 4.5

Agentic workLike-for-likePublic boards, shown as published, kept out of the index10

Agentic work benchmarks for Claude Sonnet 4.5 and Gemma 4 31B
Benchmark	Claude Sonnet 4.5	Gemma 4 31B	Leader
AA Agentic Index	15.8	4.2	Claude Sonnet 4.5
Design Arena: agents building web apps	1060	Not measured	Only Claude Sonnet 4.5 measured
Design Arena: agents building full-stack apps	1050	Not measured	Only Claude Sonnet 4.5 measured
Design Arena: agents building mobile apps	1137	Not measured	Only Claude Sonnet 4.5 measured
LiveBench research	Not measured	44.4%	Only Gemma 4 31B measured
LiveBench browser	Not measured	4.0%	Only Gemma 4 31B measured
LiveBench long agentic	Not measured	13.3%	Only Gemma 4 31B measured
τ²-Bench Telecom	Not measured	65.5%	Only Gemma 4 31B measured
METR time horizons	67.4%	Not measured	Only Claude Sonnet 4.5 measured
Remote Labor Index	2.1%	Not measured	Only Claude Sonnet 4.5 measured
GDPval	42.5%	Not measured	Only Claude Sonnet 4.5 measured
DeepResearch Bench	52.6%	Not measured	Only Claude Sonnet 4.5 measured
OSWorld	62.9%	Not measured	Only Claude Sonnet 4.5 measured
Vending-Bench 2	$3,839	Not measured	Only Claude Sonnet 4.5 measured
Neither model has a result on the other 25 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index40

Reasoning benchmarks for Claude Sonnet 4.5 and Gemma 4 31B
Benchmark	Claude Sonnet 4.5	Gemma 4 31B	Leader
GPQA Diamond	81.6%	Not measured	Only Claude Sonnet 4.5 measured
LiveBench reasoning	Not measured	68.3%	Only Gemma 4 31B measured
MMMU Pro (Vals AI)	79.3%	Not measured	Only Claude Sonnet 4.5 measured
GPQA Diamond (Artificial Analysis run)	Not measured	85.7%	Only Gemma 4 31B measured
Humanity's Last Exam (Artificial Analysis run)	Not measured	23.6%	Only Gemma 4 31B measured
GPQA Diamond (Epoch AI run)	82.3%	75.8%	Claude Sonnet 4.5
ARC-AGI	63.7%	Not measured	Only Claude Sonnet 4.5 measured
ARC-AGI-2	13.6%	Not measured	Only Claude Sonnet 4.5 measured
SimpleBench	54.3%	Not measured	Only Claude Sonnet 4.5 measured
Chess puzzles	10.0%	Not measured	Only Claude Sonnet 4.5 measured
Mystery game puzzles	17.0%	Not measured	Only Claude Sonnet 4.5 measured
EBR-bench	2.4%	Not measured	Only Claude Sonnet 4.5 measured
VPCT	39.8%	Not measured	Only Claude Sonnet 4.5 measured
LMArena Text: hard prompts	1462	1448	Claude Sonnet 4.5
LMArena Text: expert	1483	1464	Claude Sonnet 4.5
LMArena Text: hard prompts in English	1471	1456	Claude Sonnet 4.5
LMArena Vision: diagrams	Not measured	1283	Only Gemma 4 31B measured
LMArena Vision: homework	Not measured	1310	Only Gemma 4 31B measured
Neither model has a result on the other 3 boards here

MathLike-for-likePublic boards, shown as published, kept out of the index12

Math benchmarks for Claude Sonnet 4.5 and Gemma 4 31B
Benchmark	Claude Sonnet 4.5	Gemma 4 31B	Leader
AIME	88.2%	Not measured	Only Claude Sonnet 4.5 measured
MGSM (Vals AI)	94.3%	Not measured	Only Claude Sonnet 4.5 measured
OTIS Mock AIME	77.8%	73.3%	Claude Sonnet 4.5
FrontierMath, tiers 1 to 3	23.9%	Not measured	Only Claude Sonnet 4.5 measured
FrontierMath, tier 4	2.4%	Not measured	Only Claude Sonnet 4.5 measured
ProofBench	19.0%	Not measured	Only Claude Sonnet 4.5 measured
MATH level 5	97.7%	Not measured	Only Claude Sonnet 4.5 measured
LMArena Text: math	1449	1463	Gemma 4 31B
LMArena Text: mathematical work	1462	1465	Gemma 4 31B
Neither model has a result on the other 4 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index52

Knowledge benchmarks for Claude Sonnet 4.5 and Gemma 4 31B
Benchmark	Claude Sonnet 4.5	Gemma 4 31B	Leader
MMLU Pro	87.4%	Not measured	Only Claude Sonnet 4.5 measured
LegalBench (Vals AI)	84.1%	Not measured	Only Claude Sonnet 4.5 measured
CaseLaw (Vals AI)	62.2%	52.6%	Claude Sonnet 4.5
CorpFin (Vals AI)	62.0%	Not measured	Only Claude Sonnet 4.5 measured
TaxEval (Vals AI)	73.3%	Not measured	Only Claude Sonnet 4.5 measured
MortgageTax (Vals AI)	64.0%	61.4%	Claude Sonnet 4.5
MedQA (Vals AI)	94.7%	Not measured	Only Claude Sonnet 4.5 measured
MedCode (Vals AI)	44.1%	Not measured	Only Claude Sonnet 4.5 measured
SimpleQA Verified	30.7%	10.4%	Claude Sonnet 4.5
LMArena Text: science	1448	1457	Gemma 4 31B
LMArena Text: medicine and healthcare	1444	1451	Gemma 4 31B
LMArena Text: legal and government	1451	1438	Claude Sonnet 4.5
LMArena Text: business and finance	1440	1430	Claude Sonnet 4.5
Neither model has a result on the other 4 boards here

Web designDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared

Web design benchmarks for Claude Sonnet 4.5 and Gemma 4 31B
Benchmark	Claude Sonnet 4.5	Gemma 4 31B	Leader
Design Arena: websites	1190	Not measured	Only Claude Sonnet 4.5 measured
Design Arena: UI components	1173	Not measured	Only Claude Sonnet 4.5 measured
Design Arena: game dev	1166	Not measured	Only Claude Sonnet 4.5 measured
Design Arena: data viz	1167	Not measured	Only Claude Sonnet 4.5 measured
Design Arena: 3D	1158	Not measured	Only Claude Sonnet 4.5 measured
Design Arena: all code categories	1183	Not measured	Only Claude Sonnet 4.5 measured
Design Arena: SVG	1114	Not measured	Only Claude Sonnet 4.5 measured
Design Arena: ASCII art	1204	Not measured	Only Claude Sonnet 4.5 measured
LiveBench design	Not measured	58.4%	Only Gemma 4 31B measured

GeneralLike-for-likePublic boards, shown as published, kept out of the index108

General benchmarks for Claude Sonnet 4.5 and Gemma 4 31B
Benchmark	Claude Sonnet 4.5	Gemma 4 31B	Leader
LiveBench data analysis	Not measured	53.3%	Only Gemma 4 31B measured
SAGE (Vals AI)	36.1%	55.0%	Gemma 4 31B
MedScribe (Vals AI)	84.5%	Not measured	Only Claude Sonnet 4.5 measured
IFBench	Not measured	75.6%	Only Gemma 4 31B measured
Long context reasoning (AA-LCR)	Not measured	69.7%	Only Gemma 4 31B measured
DTBench	83.2%	82.7%	Claude Sonnet 4.5
LMCA	38.8%	39.3%	Gemma 4 31B
Surface Evolver Bench	Not measured	30.6%	Only Gemma 4 31B measured
LMArena Text	1438	1443	Gemma 4 31B
LMArena Text: instruction following	1459	1433	Claude Sonnet 4.5
LMArena Text: creative writing	1442	1417	Claude Sonnet 4.5
LMArena Vision	Not measured	1276	Only Gemma 4 31B measured
LMArena Text: English	1450	1451	Gemma 4 31B
LMArena Text: non-English	1425	1430	Gemma 4 31B
LMArena Text: Chinese	1460	1475	Gemma 4 31B
LMArena Text: German	1427	Not measured	Only Claude Sonnet 4.5 measured
LMArena Text: Japanese	1390	Not measured	Only Claude Sonnet 4.5 measured
LMArena Text: Korean	1402	Not measured	Only Claude Sonnet 4.5 measured
LMArena Text: French	1459	1436	Claude Sonnet 4.5
LMArena Text: Spanish	1458	1442	Claude Sonnet 4.5
LMArena Text: Russian	1437	1460	Gemma 4 31B
LMArena Text: Polish	1423	1433	Gemma 4 31B
LMArena Text: multi-turn	1465	1452	Claude Sonnet 4.5
LMArena Text: longer queries	1475	1446	Claude Sonnet 4.5
LMArena Text: writing and language	1442	1432	Claude Sonnet 4.5
LMArena Text: entertainment and media	1428	1405	Claude Sonnet 4.5
LMArena Vision: English	Not measured	1271	Only Gemma 4 31B measured
LMArena Vision: Chinese	Not measured	1326	Only Gemma 4 31B measured
LMArena Vision: reading text	Not measured	1282	Only Gemma 4 31B measured
LMArena Vision: humor	Not measured	1280	Only Gemma 4 31B measured
LMArena Vision: captioning	Not measured	1218	Only Gemma 4 31B measured
LMArena Vision: recognizing things	Not measured	1226	Only Gemma 4 31B measured
LMArena Vision: creative writing	Not measured	1285	Only Gemma 4 31B measured
LMArena Document	1450	1425	Claude Sonnet 4.5
Neither model has a result on the other 12 boards here

Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared

Image generation benchmarks for Claude Sonnet 4.5 and Gemma 4 31B
Benchmark	Claude Sonnet 4.5	Gemma 4 31B	Leader
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

Claude Sonnet 4.5$0.011Fits in one request

Gemma 4 31B$0.0004Fits in one request

Gemma 4 31B costs less

Repository review

50K input + 3K output tokens

Claude Sonnet 4.5$0.195Fits in one request

Gemma 4 31B$0.011Fits in one request

Gemma 4 31B costs less

Agent loop

200K input + 10K output tokens

Claude Sonnet 4.5$0.750Fits in one request

Gemma 4 31B$0.044Fits in one request

Gemma 4 31B 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 Claude Sonnet 4.5 and Gemma 4 31B
Specification	Anthropic Claude Sonnet 4.5	Google Gemma 4 31B
Maker	Anthropic	Google
Weights	No public weights listed	Open weights
Released	September 29, 2025	April 2, 2026
Context window	1M	262K
Input $/Mtok	$3.00	$0.20
Output $/Mtok	$15.00	$0.40
Coding index	59.1	38.3
Independent measurements behind it	2	2
Cost per solved task	$1.16	Not computable
Source	OpenRouter listing	OpenRouter listing

Questions

Is Claude Sonnet 4.5 better than Gemma 4 31B for coding?

Pick Claude Sonnet 4.5 for coding: it scores 59.1 on the Vibe Coding Index against 38.3 for Gemma 4 31B. Pick Gemma 4 31B when output tokens cost 37.5x less, or when what matters is WeirdML or LMArena Text: math, where it leads.

Which is cheaper, Claude Sonnet 4.5 or Gemma 4 31B?

Claude Sonnet 4.5 costs $3.00 per million input tokens and $15.00 per million output tokens; Gemma 4 31B costs $0.20 and $0.40. Cost per solved task is known for Claude Sonnet 4.5 only.

Which has the bigger context window, Claude Sonnet 4.5 or Gemma 4 31B?

Claude Sonnet 4.5, with 1M tokens against 262K.

How many benchmarks is the Claude Sonnet 4.5 vs Gemma 4 31B comparison based on?

42 benchmarks have a result for both models as of October 21, 2026. Claude Sonnet 4.5's coding index rests on 2 independent benchmarks and Gemma 4 31B's on 2. Where only one model has a result, the page says so instead of naming a winner.

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Decision reading

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

Math

Knowledge

Web design

Long documents

Everyday cost

Cost per solved task

At a glance

Benchmark by benchmark

What each workload costs

Chat turn

Repository review

Agent loop

Specification differences

Questions

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