Model comparison

GPT-4o vs Mercury 2.5

GPT-4o has enough public results to be ranked (#316); Mercury 2.5 does not yet, so treat this comparison as directional.

Last verified . 0 shared benchmarks.

GPT-4o OpenAI

28.5

Rank #316 Confirmed

Mercury 2.5 Inception

30.2

Unranked Sparse

Summary

  • The widest gap is in math, where Mercury 2.5 leads 22.4 to 10.2.
  • 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 Index28.530.2
Released2024-05-132026-09-08
WeightsProprietaryProprietary
Context window128K260K
Max output16K66K
Input $ / M tokens$2.50$0.04
Output $ / M tokens$10$0.15
Results tracked722

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Category by category

Coding Not comparable

GPT-4o: 25.1 (#323), Mercury 2.5: —

Coding benchmarks
BenchmarkGPT-4oMercury 2.5
SWE-bench Verified31%—
SWE-bench Verified (bash only)21.6%—
Aider Polyglot45.3%—
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: 20.8 (#133), 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 Not comparable

GPT-4o: 9.4 (#338), Mercury 2.5: —

Reasoning benchmarks
BenchmarkGPT-4oMercury 2.5
ARC-AGI-20%—
SimpleBench17.8%—
ARC-AGI-14.5%—
CritPt0%—
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: 10.2 (#303), Mercury 2.5: 22.4

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 (#235), 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: 33.9 (#85), Mercury 2.5: —

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

Multilingual Not comparable

GPT-4o: 43.4 (#181), Mercury 2.5: —

Multilingual benchmarks
BenchmarkGPT-4oMercury 2.5
LMArena Non-English1283—
LMArena Chinese1277—
LMArena French1303—
LMArena German1282—
LMArena Japanese1257—
LMArena Korean1234—
LMArena Russian1286—
LMArena Spanish1292—

Instruction Following Not comparable

GPT-4o: 66.8 (#202), 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 (#174), Mercury 2.5: —

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

Writing & Preference Not comparable

GPT-4o: 52.8 (#160), Mercury 2.5: —

Writing & Preference benchmarks
BenchmarkGPT-4oMercury 2.5
LMArena Text1300—
LMArena Creative Writing1291—
Short-Story Creative Writing81.8%—
WildBench82.8%—
LMArena Multi-Turn1302—
LiveBench Language47.6%—

Frequently asked questions

Is GPT-4o better than Mercury 2.5?

GPT-4o has enough public results to be ranked (#316); Mercury 2.5 does not yet, so treat this comparison as directional.

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.

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?

0 benchmarks have published results for both models. GPT-4o has 72 scored results on Noometry and Mercury 2.5 has 2.

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