Noometry

Model comparison

DeepSeek V4.1 Flash vs GPT-5.5 Pro

GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 50.3 on the Noometry Index. DeepSeek V4.1 Flash costs 257× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.

Last verified . 4 shared benchmarks.

DeepSeek V4.1 Flash DeepSeek

50.3

Rank #40 Confirmed

GPT-5.5 Pro OpenAI

64.3

Rank #7 Confirmed

Summary

  • They share 4 benchmarks with published results for both. DeepSeek V4.1 Flash scores higher in 0 categories and GPT-5.5 Pro in 3 categories; 3 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.5 Pro leads 83.8 to 48.4.
  • The biggest single-benchmark swing is CritPt: 14.3% for DeepSeek V4.1 Flash and 30.6% for GPT-5.5 Pro.
  • DeepSeek V4.1 Flash is cheaper at $0.15 / $0.60 per million input/output tokens, against $30 / $180 for GPT-5.5 Pro.
  • GPT-5.5 Pro accepts more context: 1.05M tokens versus 1M.
  • DeepSeek V4.1 Flash has downloadable open weights; the other is API-only.

Side by side

DeepSeek V4.1 FlashGPT-5.5 Pro
ProviderDeepSeekOpenAI
Noometry Index50.364.3
Released2026-09-092026-04-23
WeightsOpenProprietary
Context window1M1.05M
Max output393K128K
Input $ / M tokens$0.15$30
Output $ / M tokens$0.60$180
Results tracked2514

Sponsored placements are available on pages like this one. Advertise on Noometry

Category by category

Coding Not comparable

DeepSeek V4.1 Flash: 52.8 (#29), GPT-5.5 Pro: —

BenchmarkDeepSeek V4.1 FlashGPT-5.5 Pro
LMArena WebDev1620—
SciCode51.9%—
LMArena Coding1511—
ALE-Bench1,092—

Reasoning GPT-5.5 Pro leads

DeepSeek V4.1 Flash: 46.2 (#39), GPT-5.5 Pro: 73.6 (#7)

BenchmarkDeepSeek V4.1 FlashGPT-5.5 Pro
CritPt14.3%30.6%
DTBench89.9%96%
LMCA47%53.9%
Epoch Capabilities Index155.01162.45
ARC-AGI-2—84.6%
SimpleBench—76.9%
NYT Connections (extended)89.6%—
ARC-AGI-1—96.5%
Chess Puzzles—64%
LMArena Hard Prompts1485—
Surface Evolver Bench46.3%—

Math GPT-5.5 Pro leads

DeepSeek V4.1 Flash: 48.4 (#52), GPT-5.5 Pro: 83.8 (#8)

BenchmarkDeepSeek V4.1 FlashGPT-5.5 Pro
FrontierMath (Tiers 1-3)—87.7%
FrontierMath Tier 4—78%
OTIS Mock AIME 2024-2025—100%
ProofBench54%—
LMArena Math1493—
FrontierMath (Feb 2025 set)—52.4%
FrontierMath Tier 4 (v1)—39.6%

Knowledge GPT-5.5 Pro leads

DeepSeek V4.1 Flash: 41.6 (#97), GPT-5.5 Pro: 64.2 (#17)

BenchmarkDeepSeek V4.1 FlashGPT-5.5 Pro
GPQA Diamond—93.9%
LMArena Expert1505—

Multilingual Not comparable

DeepSeek V4.1 Flash: 55.5 (#29), GPT-5.5 Pro: —

BenchmarkDeepSeek V4.1 FlashGPT-5.5 Pro
LMArena Non-English1452—
LMArena Chinese1506—
LMArena French1448—
LMArena Russian1473—
LMArena Spanish1499—

Instruction Following Not comparable

DeepSeek V4.1 Flash: 77.6 (#24), GPT-5.5 Pro: —

BenchmarkDeepSeek V4.1 FlashGPT-5.5 Pro
LMArena Instruction Following1475—

Long Context Not comparable

DeepSeek V4.1 Flash: 45.2 (#46), GPT-5.5 Pro: —

BenchmarkDeepSeek V4.1 FlashGPT-5.5 Pro
LMArena Longer Query1476—

Writing & Preference Not comparable

DeepSeek V4.1 Flash: 65.8 (#43), GPT-5.5 Pro: —

BenchmarkDeepSeek V4.1 FlashGPT-5.5 Pro
LMArena Text1465—
LMArena Creative Writing1436—
EQ-Bench Creative Writing1540—
LMArena Multi-Turn1460—

Frequently asked questions

Is DeepSeek V4.1 Flash better than GPT-5.5 Pro?

GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 50.3 on the Noometry Index. DeepSeek V4.1 Flash costs 257× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.

Which is cheaper, DeepSeek V4.1 Flash or GPT-5.5 Pro?

DeepSeek V4.1 Flash is cheaper. It lists at $0.15 per million input tokens and $0.60 per million output tokens; GPT-5.5 Pro lists at $30 and $180.

Which has the bigger context window?

GPT-5.5 Pro does, with 1.05M tokens against 1M.

How many benchmarks do DeepSeek V4.1 Flash and GPT-5.5 Pro share?

4 benchmarks have published results for both models. DeepSeek V4.1 Flash has 25 scored results on Noometry and GPT-5.5 Pro has 14.

Related comparisons

Go deeper