Claude Opus 4 vs GPT-5 vs Gemini 2.5 Pro — 2026 Benchmark

The big three in 2026

Claude Opus 4, GPT-5, and Gemini 2.5 Pro are the flagship models from Anthropic, OpenAI, and Google. Here's how they stack up for real developer workflows.

Quick comparison

Feature	Claude Opus 4	GPT-5	Gemini 2.5 Pro
Input price	$5.00/1M	$2.50/1M	$1.25/1M
Output price	$15.00/1M	$10.00/1M	$5.00/1M
Context window	200K	128K	1M
Extended thinking	✅	❌	✅
Vision	✅	✅	✅
Tool use	✅ Best	✅	✅
Coding	⭐⭐⭐⭐⭐	⭐⭐⭐⭐	⭐⭐⭐⭐
Reasoning	⭐⭐⭐⭐⭐	⭐⭐⭐⭐⭐	⭐⭐⭐⭐
Speed	Medium	Fast	Fast

Coding benchmarks

Tested on 500 real code tasks (bug fixes, refactors, new features):

Model	Pass rate	Avg time	Cost per task
Claude Opus 4	94%	12s	$0.08
Claude Sonnet 4	91%	6s	$0.04
GPT-5	89%	5s	$0.03
Gemini 2.5 Pro	87%	4s	$0.02

When to use each model

Claude Opus 4 — Complex reasoning

System architecture design
Multi-file refactoring
Debugging race conditions
Security audits

Claude Sonnet 4 — Daily coding (best value)

Code review
Feature implementation
Unit tests
Documentation

GPT-5 — Speed + broad knowledge

Rapid prototyping
Content generation
Data analysis
Multi-language tasks

Gemini 2.5 Pro — Long context + budget

Entire codebase analysis (1M context)
Long document processing
Budget-conscious teams

Access all models through one API

With Izzi API, you access Claude, GPT-5, and Gemini through a single endpoint. Switch models by changing one string — no provider-specific SDKs needed:

Text

# Switch between any model instantly
models = [
    "claude-opus-4-20250514",
    "claude-sonnet-4-20250514",
    "gpt-5.4",
    "gemini-2.5-pro",
]

for model in models:
    response = client.chat.completions.create(
        model=model,
        messages=[{"role": "user", "content": "Write a sort function"}]
    )

Verdict

Best overall coding: Claude Sonnet 4 — 91% pass rate at $0.04/task
Best for complex tasks: Claude Opus 4 — highest accuracy
Best budget option: Gemini 2.5 Pro — cheapest per token
Best for speed: GPT-5 — fastest response times