Noometry

Model comparison

GPT-5.5 Pro vs Mistral Medium 3.5

GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 40.2 on the Noometry Index. Mistral Medium 3.5 costs 23× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.

Last verified . 1 shared benchmarks.

GPT-5.5 Pro OpenAI

64.3

Rank #8 Confirmed

Mistral Medium 3.5 Mistral AI

40.2

Rank #152 Confirmed

Summary

  • They share 1 benchmark with published results for both. GPT-5.5 Pro scores higher in 3 categories and Mistral Medium 3.5 in 0 categories; 3 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-5.5 Pro leads 73.3 to 17.3.
  • Mistral Medium 3.5 is cheaper at $1.50 / $7.50 per million input/output tokens, against $30 / $180 for GPT-5.5 Pro.
  • GPT-5.5 Pro accepts more context: 1.05M tokens versus 262K.
  • Mistral Medium 3.5 has downloadable open weights; the other is API-only.

Side by side

GPT-5.5 ProMistral Medium 3.5
ProviderOpenAIMistral AI
Noometry Index64.340.2
Released2026-04-23—
WeightsProprietaryOpen
Context window1.05M262K
Max output128K210K
Input $ / M tokens$30$1.50
Output $ / M tokens$180$7.50
Results tracked1422

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

Category by category

Coding Not comparable

GPT-5.5 Pro: —, Mistral Medium 3.5: 36.0 (#213)

BenchmarkGPT-5.5 ProMistral Medium 3.5
LMArena WebDev—1264
LMArena Coding—1461

Reasoning GPT-5.5 Pro leads

GPT-5.5 Pro: 73.3 (#10), Mistral Medium 3.5: 17.3 (#295)

BenchmarkGPT-5.5 ProMistral Medium 3.5
Epoch Capabilities Index162.07141.35
ARC-AGI-284.6%—
SimpleBench76.9%—
Kagi LLM Benchmark—41.4%
NYT Connections (extended)—12.9%
ARC-AGI-196.5%—
CritPt30.6%—
Chess Puzzles64%—
LMArena Hard Prompts—1436
DTBench96%—
LMCA53.9%—

Math GPT-5.5 Pro leads

GPT-5.5 Pro: 84.0 (#10), Mistral Medium 3.5: 39.1 (#113)

BenchmarkGPT-5.5 ProMistral Medium 3.5
FrontierMath (Tiers 1-3)87.7%—
FrontierMath Tier 478%—
OTIS Mock AIME 2024-2025100%—
LMArena Math—1431
FrontierMath (Feb 2025 set)52.4%—
FrontierMath Tier 4 (v1)39.6%—

Knowledge GPT-5.5 Pro leads

GPT-5.5 Pro: 64.1 (#19), Mistral Medium 3.5: 40.0 (#126)

BenchmarkGPT-5.5 ProMistral Medium 3.5
GPQA Diamond93.9%—
LMArena Expert—1432

Multimodal Not comparable

GPT-5.5 Pro: —, Mistral Medium 3.5: 38.3 (#65)

BenchmarkGPT-5.5 ProMistral Medium 3.5
LMArena Vision—1223

Multilingual Not comparable

GPT-5.5 Pro: —, Mistral Medium 3.5: 51.9 (#100)

BenchmarkGPT-5.5 ProMistral Medium 3.5
LMArena Non-English—1404
LMArena Chinese—1442
LMArena French—1448
LMArena German—1451
LMArena Korean—1385
LMArena Russian—1395
LMArena Spanish—1409

Instruction Following Not comparable

GPT-5.5 Pro: —, Mistral Medium 3.5: 74.6 (#90)

BenchmarkGPT-5.5 ProMistral Medium 3.5
LMArena Instruction Following—1415

Long Context Not comparable

GPT-5.5 Pro: —, Mistral Medium 3.5: 43.2 (#103)

BenchmarkGPT-5.5 ProMistral Medium 3.5
LMArena Longer Query—1415

Writing & Preference Not comparable

GPT-5.5 Pro: —, Mistral Medium 3.5: 58.5 (#117)

BenchmarkGPT-5.5 ProMistral Medium 3.5
LMArena Text—1421
LMArena Creative Writing—1374
EQ-Bench 4—993
LMArena Multi-Turn—1423

Frequently asked questions

Is GPT-5.5 Pro better than Mistral Medium 3.5?

GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 40.2 on the Noometry Index. Mistral Medium 3.5 costs 23× 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, GPT-5.5 Pro or Mistral Medium 3.5?

Mistral Medium 3.5 is cheaper. It lists at $1.50 per million input tokens and $7.50 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 262K.

How many benchmarks do GPT-5.5 Pro and Mistral Medium 3.5 share?

1 benchmark has published results for both models. GPT-5.5 Pro has 14 scored results on Noometry and Mistral Medium 3.5 has 22.

Related comparisons

Go deeper