Model comparison

GPT-4o vs Mercury 2.5

Mercury 2.5 is the stronger model overall, scoring 33.5 to 28.6 on the Noometry Index.

Last verified . 1 shared benchmarks.

GPT-4o OpenAI

28.6

Rank #324 Confirmed

Mercury 2.5 Inception

33.5

Rank #242 Reported

Summary

  • They share 1 benchmark with published results for both. GPT-4o scores higher in 0 categories and Mercury 2.5 in 3 categories; 3 gaps are clear of the uncertainty.
  • The widest gap is in coding, where Mercury 2.5 leads 39.5 to 24.8.
  • Mercury 2.5 is cheaper at $0.04 / $0.15 per million input/output tokens, against $2.50 / $10 for GPT-4o.
  • Mercury 2.5 accepts more context: 260K tokens versus 128K.

Side by side

GPT-4o and Mercury 2.5 specifications
GPT-4oMercury 2.5
ProviderOpenAIInception
Noometry Index28.633.5
Released2024-05-132026-09-08
WeightsProprietaryProprietary
Context window128K260K
Max output16K66K
Input $ / M tokens$2.50$0.04
Output $ / M tokens$10$0.15
Results tracked724

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Category by category

Coding Mercury 2.5 leads

GPT-4o: 24.8 (#328), Mercury 2.5: 39.5 (#156)

Coding benchmarks
BenchmarkGPT-4oMercury 2.5
SWE-bench Verified31%—
SWE-bench Verified (bash only)21.6%—
Aider Polyglot45.3%—
SciCode—38.5%
GSO0%—
WeirdML25.1%—
BigCodeBench Instruct51.1%—
LiveBench Coding51.4%—
LMArena Coding1297—
BigCodeBench Complete61.1%—
CadEval26%—
ALE-Bench—301.65
HumanEval+87.2%—
MBPP+72.2%—

Agentic & Tool Use Not comparable

GPT-4o: 21.0 (#141), Mercury 2.5: —

Agentic & Tool Use benchmarks
BenchmarkGPT-4oMercury 2.5
GDPval9.9%—
TheAgentCompany8.6%—
Cybench12.5%—
BALROG32.3%—
LMArena Search1006—
METR Time Horizons40.8%—

Reasoning Mercury 2.5 leads

GPT-4o: 9.4 (#343), Mercury 2.5: 22.4 (#193)

Reasoning benchmarks
BenchmarkGPT-4oMercury 2.5
CritPt0%0%
ARC-AGI-20%—
SimpleBench17.8%—
ARC-AGI-14.5%—
Chess Puzzles13%—
EnigmaEval0.8%—
LiveBench Reasoning55.8%—
LMArena Hard Prompts1281—
DTBench64.5%—
LiveBench Data Analysis60.9%—
LMCA16.6%—
Epoch Capabilities Index128.97—
ForecastBench57.7—
LiveBench55.3%—

Math Mercury 2.5 leads

GPT-4o: 10.6 (#312), Mercury 2.5: 23.3 (#272)

Math benchmarks
BenchmarkGPT-4oMercury 2.5
FrontierMath (Tiers 1-3)0.4%—
OTIS Mock AIME 2024-20256.4%—
ProofBench—3%
Omni-MATH29.3%—
LiveBench Math49.5%—
LMArena Math1285—
MATH Level 553.3%—
FrontierMath (Feb 2025 set)0.3%—

Knowledge Not comparable

GPT-4o: 28.8 (#242), Mercury 2.5: —

Knowledge benchmarks
BenchmarkGPT-4oMercury 2.5
GPQA Diamond49.2%—
Humanity's Last Exam2.7%—
SimpleQA Verified26%—
MMLU-Pro71.3%—
Confabulations15.3%—
Vectara Hallucination Rate9.6%—
GPQA (HELM)52%—
LMArena Expert1250—
MMLU88.1%—

Multimodal Not comparable

GPT-4o: 34.5 (#91), Mercury 2.5: —

Multimodal benchmarks
BenchmarkGPT-4oMercury 2.5
LMArena Vision1137—
Video-MME71.9%—
GeoBench71%—
VPCT40%—
ScienceQA88.5%—

Multilingual Not comparable

GPT-4o: 43.2 (#186), Mercury 2.5: —

Multilingual benchmarks
BenchmarkGPT-4oMercury 2.5
LMArena Non-English1283—
LMArena Chinese1277—
LMArena French1304—
LMArena German1282—
LMArena Japanese1257—
LMArena Korean1234—
LMArena Russian1286—
LMArena Spanish1292—

Instruction Following Not comparable

GPT-4o: 66.6 (#207), Mercury 2.5: —

Instruction Following benchmarks
BenchmarkGPT-4oMercury 2.5
LiveBench Instruction Following68.6%—
IFEval81.7%—
LMArena Instruction Following1278—

Long Context Not comparable

GPT-4o: 39.4 (#179), Mercury 2.5: —

Long Context benchmarks
BenchmarkGPT-4oMercury 2.5
Fiction.LiveBench66.7%—
LMArena Longer Query1289—

Writing & Preference Not comparable

GPT-4o: 52.6 (#166), Mercury 2.5: —

Writing & Preference benchmarks
BenchmarkGPT-4oMercury 2.5
LMArena Text1300—
LMArena Creative Writing1292—
Short-Story Creative Writing81.8%—
WildBench82.8%—
LMArena Multi-Turn1302—
LiveBench Language47.6%—

Frequently asked questions

Is GPT-4o better than Mercury 2.5?

Mercury 2.5 is the stronger model overall, scoring 33.5 to 28.6 on the Noometry Index.

Which is cheaper, GPT-4o or Mercury 2.5?

Mercury 2.5 is cheaper. It lists at $0.04 per million input tokens and $0.15 per million output tokens; GPT-4o lists at $2.50 and $10.

Is GPT-4o or Mercury 2.5 better for coding?

Mercury 2.5 scores higher on coding benchmarks: 39.5 versus 24.8 in the Noometry coding category.

Which has the bigger context window?

Mercury 2.5 does, with 260K tokens against 128K.

How many benchmarks do GPT-4o and Mercury 2.5 share?

1 benchmark has published results for both models. GPT-4o has 72 scored results on Noometry and Mercury 2.5 has 4.

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