Which Language Model
Should You Use?
Compare GPT-5, Claude Opus 4.6, Llama 4, Gemini 2.5, and other 2026 LLMs across standard benchmarks. From language understanding (MMLU) to mathematical reasoning (GSM8K, MATH) to code generation (HumanEval, SWE-bench).
What Makes a Good Language Model?
LLMs are evaluated across multiple dimensions. No single benchmark tells the full story. Here's what we track:
General Knowledge
How well does the model understand the world? Tested via MMLU (57 academic subjects), ARC (science), and HellaSwag (common sense).
Reasoning Ability
Can the model think through complex problems? Measured via GSM8K (grade-school math), MATH (competition problems), and GPQA (expert reasoning).
Code Generation
Programming proficiency via HumanEval (function synthesis), MBPP (Python basics), and SWE-bench (real-world debugging).
Multimodal Understanding
Vision capabilities tested via MMMU (college-level reasoning), MathVista (visual math), and ChartQA (data interpretation).
Key Benchmarks
Language Understanding
General knowledge, reading comprehension, and language tasks
MMLU
SOTA: 92.3%57 subjects from STEM to humanities
HellaSwag
SOTA: 96.2%Commonsense reasoning
ARC
SOTA: 97.1%Grade-school science questions
TruthfulQA
SOTA: 91.0%Factual accuracy and truthfulness
Reasoning & Math
Mathematical problem solving and logical reasoning
Code Generation
Programming ability and software engineering
Multimodal
Vision, image understanding, and cross-modal tasks
MMMU
SOTA: 74.2%College-level multimodal understanding
MathVista
SOTA: 72.8%Visual mathematical reasoning
AI2D
SOTA: 95.1%Diagram understanding
ChartQA
SOTA: 87.6%Chart and graph comprehension
Model Families
The major LLM providers and their model series. Each family targets different use cases and price points.
GPT Series
OpenAI
GPT-5.4, GPT-5.3-Codex, GPT-5.2, GPT-5.1, o4-mini
Claude
Anthropic
Claude Opus 4.6, Claude Sonnet 4.6, Claude Haiku 4.5
Gemini
Gemini 3.1 Pro, Gemini 3 Flash, Gemini 2.5 Pro, Gemini 2.5 Flash
DeepSeek
DeepSeek
DeepSeek V3.2, DeepSeek R1
Grok
xAI
Grok 4.1 Fast, Grok 4 Fast
MiniMax
MiniMax
MiniMax M2.5
Kimi
Moonshot AI
Kimi K2.5
GLM
Z.ai
GLM 5, GLM 5 Turbo
Mistral
Mistral AI
Mistral Small 4, Mistral Large 3, Codestral
Llama
Meta
Llama 4 Scout, Llama 4 Maverick, Llama 3.3 70B
Most Used Models
Source: OpenRouterReal usage data from millions of developers routing through OpenRouter. Based on weekly token volume.
Provider Market Share
Quality Rankings
OpenRouter's composite quality score based on Arena Elo and multi-benchmark evaluation.
Gemini 3.1 Pro Preview
GPT-5.4
OpenAI
GPT-5.3-Codex
OpenAI
Claude Opus 4.6
Anthropic
Claude Sonnet 4.6
Anthropic
GPT-5.2
OpenAI
GLM 5
Z.ai
Claude Opus 4.5
Anthropic
Gemini 3 Pro Preview
GPT-5.1
OpenAI
Data from OpenRouter rankings, scraped March 17 2026. Scores are OpenRouter's composite quality metric.
Understanding the Metrics
MMLU (Massive Multitask Language Understanding)
Multiple-choice questions across 57 subjects from elementary math to professional law. The most comprehensive test of general knowledge.
GSM8K (Grade School Math 8K)
8,500 grade-school level math word problems requiring multi-step reasoning. Tests basic mathematical reasoning ability.
HumanEval
164 Python programming problems. Model must generate a function that passes unit tests. The standard for measuring code generation ability.
GPQA (Graduate-Level Google-Proof Q&A)
Expert-written questions in biology, physics, and chemistry designed to be difficult even for domain experts. Tests deep reasoning.
Explore Related Benchmarks
Why Our LLM Benchmarks Are Different
Verified Results Only
No marketing claims. We cite published papers, official leaderboards, and third-party evaluations. Every number is traceable.
Consistent Methodology
Same evaluation protocol for all models. We note when vendors use different prompting strategies or few-shot examples.
Regular Updates
New models release weekly. We track the latest results as papers publish and maintain historical trends.
Frequently Asked Questions
What's the difference between GPT-4 and GPT-4o?
GPT-4o is the "omni" version with native multimodal capabilities (vision, audio). It's faster and cheaper than GPT-4 while maintaining similar benchmark scores on text tasks. GPT-4o is now the default model at OpenAI.
Are open-source LLMs competitive with GPT-4?
In 2026, open-source models have largely closed the gap. Llama 4 Maverick, Qwen 3, and DeepSeek R1 achieve competitive performance across MMLU, HumanEval, and reasoning tasks. The trade-off is now primarily about hosting complexity vs API convenience.
Why do benchmark scores vary across sources?
Different evaluation setups: 0-shot vs few-shot prompting, exact wording of system prompts, temperature settings, and whether chain-of-thought is used. We document these differences in our benchmark methodology notes.
Which benchmark best predicts real-world performance?
Depends on your use case. For coding assistants, check SWE-bench. For tutoring/QA, MMLU matters. For math/analysis, GSM8K and MATH. No single metric captures everything. That's why we track multiple benchmarks.
Explore LLM Benchmark Data Tracked Across 50+ Models
Compare MMLU, GSM8K, HumanEval, SWE-bench, and more across every major model family updated for 2026.