Model comparison

DeepSeek-V3.1 vs GPT-5.5

GPT-5.5 is the stronger model overall, scoring 63.4 to 42.8 on the Noometry Index. DeepSeek-V3.1 costs 26× less per token, which makes it the better buy when GPT-5.5's lead doesn't matter for your workload.

Last verified . 26 shared benchmarks.

DeepSeek-V3.1 DeepSeek

42.8

Rank #108 Confirmed

GPT-5.5 OpenAI

63.4

Rank #9 Confirmed

Summary

  • They share 26 benchmarks with published results for both. DeepSeek-V3.1 scores higher in 0 categories and GPT-5.5 in 8 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-5.5 leads 72.8 to 27.9.
  • The biggest single-benchmark swing is WeirdML: 38.4% for DeepSeek-V3.1 and 84.9% for GPT-5.5.
  • DeepSeek-V3.1 is cheaper at $0.25 / $0.95 per million input/output tokens, against $5 / $30 for GPT-5.5.
  • GPT-5.5 accepts more context: 1.05M tokens versus 164K.
  • DeepSeek-V3.1 has downloadable open weights; the other is API-only.

Side by side

DeepSeek-V3.1 and GPT-5.5 specifications
DeepSeek-V3.1GPT-5.5
ProviderDeepSeekOpenAI
Noometry Index42.863.4
Released2025-08-212026-04-23
WeightsOpenProprietary
Context window164K1.05M
Max output8K128K
Input $ / M tokens$0.25$5
Output $ / M tokens$0.95$30
Results tracked2771

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Category by category

Coding GPT-5.5 leads

DeepSeek-V3.1: 40.3 (#144), GPT-5.5: 58.2 (#17)

Coding benchmarks
BenchmarkDeepSeek-V3.1GPT-5.5
WeirdML38.4%84.9%
LMArena Coding14171494
SWE-bench Verified—80.6%
DeepSWE—67%
FrontierCode—43%
LMArena WebDev—1513
SciCode—56.1%
GSO—40.2%
MirrorCode—10%
ALE-Bench—1,943

Agentic & Tool Use Not comparable

DeepSeek-V3.1: —, GPT-5.5: 50.7 (#6)

Agentic & Tool Use benchmarks
BenchmarkDeepSeek-V3.1GPT-5.5
Terminal-Bench—84.7%
APEX-Agents—55.1%
OSWorld 2.0—13%
Remote Labor Index—6.3%
τ²-bench Banking—44.6%
DeepResearch Bench—54%
PostTrainBench—27.2%
ExploitBench—47.4%
GBAEval—53.2%
GDP.pdf—26%
LMArena Search—1242
Vending-Bench 2—7,524

Reasoning GPT-5.5 leads

DeepSeek-V3.1: 27.9 (#110), GPT-5.5: 72.8 (#11)

Reasoning benchmarks
BenchmarkDeepSeek-V3.1GPT-5.5
SimpleBench40%69%
Kagi LLM Benchmark53.2%88.8%
LMArena Hard Prompts14171489
DTBench82.7%96%
LMCA24.3%54.3%
Epoch Capabilities Index139.92159.1
ForecastBench5860.6
ARC-AGI-2—85%
NYT Connections (extended)—96.2%
ARC-AGI-1—95%
CritPt—27.1%
Chess Puzzles—54%
EBR-Bench—34.3%
Mystery Game Puzzles—56%
Surface Evolver Bench—88.1%
Bench to the Future 3—0.14

Math GPT-5.5 leads

DeepSeek-V3.1: 38.9 (#122), GPT-5.5: 81.7 (#11)

Knowledge GPT-5.5 leads

DeepSeek-V3.1: 43.7 (#90), GPT-5.5: 64.4 (#17)

Knowledge benchmarks
BenchmarkDeepSeek-V3.1GPT-5.5
Vectara Hallucination Rate5.5%9.3%
LMArena Expert14051508
GPQA Diamond—94%
SimpleQA Verified—63%

Multimodal Not comparable

DeepSeek-V3.1: —, GPT-5.5: 46.9 (#12)

Multimodal benchmarks
BenchmarkDeepSeek-V3.1GPT-5.5
LMArena Vision—1297
Blueprint-Bench 2—36.2%
Furniture Assembly—44.2%
LMArena Document—1486

Multilingual GPT-5.5 leads

DeepSeek-V3.1: 51.6 (#106), GPT-5.5: 56.4 (#20)

Multilingual benchmarks
BenchmarkDeepSeek-V3.1GPT-5.5
LMArena Non-English14001467
LMArena Chinese14691533
LMArena French14471486
LMArena German14111480
LMArena Japanese13781498
LMArena Korean13371460
LMArena Russian14051473
LMArena Spanish14311468

Instruction Following GPT-5.5 leads

DeepSeek-V3.1: 73.9 (#110), GPT-5.5: 77.5 (#18)

Instruction Following benchmarks
BenchmarkDeepSeek-V3.1GPT-5.5
LMArena Instruction Following14001479

Long Context GPT-5.5 leads

DeepSeek-V3.1: 36.3 (#232), GPT-5.5: 48.3 (#12)

Long Context benchmarks
BenchmarkDeepSeek-V3.1GPT-5.5
LMArena Longer Query14221484
Fiction.LiveBench52.8%—
CL-bench Life—22.2%

Writing & Preference GPT-5.5 leads

DeepSeek-V3.1: 60.3 (#98), GPT-5.5: 72.7 (#13)

Writing & Preference benchmarks
BenchmarkDeepSeek-V3.1GPT-5.5
LMArena Text14201472
LMArena Creative Writing14011455
EQ-Bench Creative Writing14361844
LMArena Multi-Turn14081476
EQ-Bench 4—1315

Frequently asked questions

Is DeepSeek-V3.1 better than GPT-5.5?

GPT-5.5 is the stronger model overall, scoring 63.4 to 42.8 on the Noometry Index. DeepSeek-V3.1 costs 26× less per token, which makes it the better buy when GPT-5.5's lead doesn't matter for your workload.

Which is cheaper, DeepSeek-V3.1 or GPT-5.5?

DeepSeek-V3.1 is cheaper. It lists at $0.25 per million input tokens and $0.95 per million output tokens; GPT-5.5 lists at $5 and $30.

Is DeepSeek-V3.1 or GPT-5.5 better for coding?

GPT-5.5 scores higher on coding benchmarks: 58.2 versus 40.3 in the Noometry coding category.

Which has the bigger context window?

GPT-5.5 does, with 1.05M tokens against 164K.

How many benchmarks do DeepSeek-V3.1 and GPT-5.5 share?

26 benchmarks have published results for both models. DeepSeek-V3.1 has 27 scored results on Noometry and GPT-5.5 has 71.

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