Model comparison

Claude Sonnet 5 vs DeepSeek-V3.1

Claude Sonnet 5 is the stronger model overall, scoring 54.6 to 42.8 on the Noometry Index. DeepSeek-V3.1 costs 9.4× less per token, which makes it the better buy when Claude Sonnet 5's lead doesn't matter for your workload.

Last verified October 10, 2026. 24 shared benchmarks.

Claude Sonnet 5 Anthropic

54.6

Rank #29 Confirmed

DeepSeek-V3.1

DeepSeek

42.8

Rank #108 Confirmed

Summary

They share 24 benchmarks with published results for both. Claude Sonnet 5 scores higher in 8 categories and DeepSeek-V3.1 in 0 categories; 8 gaps are clear of the uncertainty.
The widest gap is in math, where Claude Sonnet 5 leads 66.2 to 38.9.
The biggest single-benchmark swing is WeirdML: 68.8% for Claude Sonnet 5 and 38.4% for DeepSeek-V3.1.
DeepSeek-V3.1 is cheaper at $0.25 / $0.95 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.
Claude Sonnet 5 accepts more context: 1M tokens versus 164K.
DeepSeek-V3.1 has downloadable open weights; the other is API-only.

Side by side

Claude Sonnet 5 and DeepSeek-V3.1 specifications
	Claude Sonnet 5	DeepSeek-V3.1
Provider	Anthropic	DeepSeek
Noometry Index	54.6	42.8
Released	2026-06-29	2025-08-21
Weights	Proprietary	Open
Context window	1M	164K
Max output	128K	8K
Input $ / M tokens	$2	$0.25
Output $ / M tokens	$10	$0.95
Results tracked	51	27

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Category by category

Coding Claude Sonnet 5 leads

Claude Sonnet 5: 55.5 (#26), DeepSeek-V3.1: 40.3 (#144)

Coding benchmarks
Benchmark	Claude Sonnet 5	DeepSeek-V3.1
WeirdML	68.8%	38.4%
LMArena Coding	1483	1417
DeepSWE	53.8%	—
FrontierCode	42.7%	—
CursorBench	34.1%	—
LMArena WebDev	1541	—
SciCode	54.3%	—
GSO	37.3%	—
ALE-Bench	1,463	—

Agentic & Tool Use Not comparable

Claude Sonnet 5: 42.8 (#18), DeepSeek-V3.1: —

Agentic & Tool Use benchmarks
Benchmark	Claude Sonnet 5	DeepSeek-V3.1
APEX-Agents	54.5%	—
GBAEval	65.3%	—
LMArena Search	1194	—
Vending-Bench 2	6,378	—

Reasoning Claude Sonnet 5 leads

Claude Sonnet 5: 49.1 (#39), DeepSeek-V3.1: 27.9 (#110)

Reasoning benchmarks
Benchmark	Claude Sonnet 5	DeepSeek-V3.1
SimpleBench	60.6%	40%
LMArena Hard Prompts	1461	1417
DTBench	92.5%	82.7%
LMCA	50%	24.3%
Epoch Capabilities Index	156.21	139.92
ForecastBench	61.1	58
Kagi LLM Benchmark	—	53.2%
NYT Connections (extended)	75.1%	—
CritPt	16.9%	—
Chess Puzzles	35%	—
Mystery Game Puzzles	35%	—
Surface Evolver Bench	60%	—
Bench to the Future 3	0.14	—

Math Claude Sonnet 5 leads

Claude Sonnet 5: 66.2 (#27), DeepSeek-V3.1: 38.9 (#122)

Math benchmarks
Benchmark	Claude Sonnet 5	DeepSeek-V3.1
LMArena Math	1467	1420
FrontierMath (Tiers 1-3)	65.6%	—
FrontierMath Tier 4	29.3%	—
OTIS Mock AIME 2024-2025	94.7%	—
ProofBench	77%	—

Knowledge Claude Sonnet 5 leads

Claude Sonnet 5: 55.6 (#47), DeepSeek-V3.1: 43.7 (#90)

Knowledge benchmarks
Benchmark	Claude Sonnet 5	DeepSeek-V3.1
LMArena Expert	1490	1405
GPQA Diamond	90.5%	—
SimpleQA Verified	33.7%	—
Vectara Hallucination Rate	—	5.5%

Multimodal Not comparable

Claude Sonnet 5: 42.4 (#31), DeepSeek-V3.1: —

Multimodal benchmarks
Benchmark	Claude Sonnet 5	DeepSeek-V3.1
LMArena Vision	1274	—
Blueprint-Bench 2	24.9%	—
LMArena Document	1466	—

Multilingual Claude Sonnet 5 leads

Claude Sonnet 5: 53.8 (#55), DeepSeek-V3.1: 51.6 (#106)

Multilingual benchmarks
Benchmark	Claude Sonnet 5	DeepSeek-V3.1
LMArena Non-English	1431	1400
LMArena Chinese	1477	1469
LMArena French	1460	1447
LMArena German	1440	1411
LMArena Japanese	1422	1378
LMArena Korean	1411	1337
LMArena Russian	1451	1405
LMArena Spanish	1437	1431

Instruction Following Claude Sonnet 5 leads

Claude Sonnet 5: 76.3 (#41), DeepSeek-V3.1: 73.9 (#110)

Instruction Following benchmarks
Benchmark	Claude Sonnet 5	DeepSeek-V3.1
LMArena Instruction Following	1452	1400

Long Context Claude Sonnet 5 leads

Claude Sonnet 5: 44.8 (#55), DeepSeek-V3.1: 36.3 (#232)

Long Context benchmarks
Benchmark	Claude Sonnet 5	DeepSeek-V3.1
LMArena Longer Query	1463	1422
Fiction.LiveBench	—	52.8%

Writing & Preference Claude Sonnet 5 leads

Claude Sonnet 5: 69.2 (#25), DeepSeek-V3.1: 60.3 (#98)

Writing & Preference benchmarks
Benchmark	Claude Sonnet 5	DeepSeek-V3.1
LMArena Text	1442	1420
LMArena Creative Writing	1416	1401
EQ-Bench Creative Writing	1794	1436
LMArena Multi-Turn	1454	1408
EQ-Bench 4	1236	—

Frequently asked questions

Is Claude Sonnet 5 better than DeepSeek-V3.1?

Which is cheaper, Claude Sonnet 5 or DeepSeek-V3.1?

DeepSeek-V3.1 is cheaper. It lists at $0.25 per million input tokens and $0.95 per million output tokens; Claude Sonnet 5 lists at $2 and $10.

Is Claude Sonnet 5 or DeepSeek-V3.1 better for coding?

Claude Sonnet 5 scores higher on coding benchmarks: 55.5 versus 40.3 in the Noometry coding category.

Which has the bigger context window?

Claude Sonnet 5 does, with 1M tokens against 164K.

How many benchmarks do Claude Sonnet 5 and DeepSeek-V3.1 share?

24 benchmarks have published results for both models. Claude Sonnet 5 has 51 scored results on Noometry and DeepSeek-V3.1 has 27.