Claude vs GPT-5: A Detailed Comparison

The question comes up constantly in developer forums, Slack channels, and team meetings: should we use Claude or ChatGPT? It's become the defining rivalry of the AI era, with both Anthropic and OpenAI pushing their models to new heights. As we head into 2026, GPT-5 and Claude Opus 4.5 have arrived—here's where things stand.

The Latest Releases

Claude Opus 4.5 launched November 24, 2025 as Anthropic's new flagship. It's described as "intelligent, efficient, and the best model in the world for coding, agents, and computer use." The model achieves state-of-the-art performance on SWE-bench Verified and leads across 7 of 8 programming languages on SWE-bench Multilingual—with dramatically improved efficiency using up to 65% fewer tokens than competing models.

GPT-5 arrived August 7, 2025, followed by GPT-5.1 in November. GPT-5 isn't a single model but a system of models working together through a real-time "router" that automatically selects the best approach for each task. It achieves 94.6% on AIME 2025 math (100% with thinking mode) and has dramatically reduced hallucinations—~80% less likely to contain factual errors than previous models.

The Market Has Shifted

The enterprise AI landscape has seen dramatic changes. OpenAI's enterprise market share dropped from 50% to 34% through 2024-2025, while Anthropic doubled from 12% to 24%. With both releasing powerful new models, the competition is tighter than ever. 46% of enterprises cite security and safety as primary switching factors—an area where Claude maintains an edge with its constitutional AI approach and improved robustness against prompt injection attacks.

The Coding Question

Both models are now genuinely excellent for software development, but excel in different scenarios.

Claude Opus 4.5 achieves state-of-the-art performance on SWE-bench Verified and leads across 7 of 8 programming languages on SWE-bench Multilingual. It shows a 10.6% improvement over Sonnet 4.5 on Aider Polyglot and 29% improvement on Vending-Bench. Critically, it does this with remarkable efficiency—matching previous performance while using 76% fewer output tokens at medium effort.

GPT-5 dominates on Aider Polyglot multi-language benchmarks at 88% and excels in mathematical problem-solving. It's been fine-tuned for agentic coding products like Cursor, Windsurf, GitHub Copilot, and Codex CLI.

What sets Claude Opus 4.5 apart is that it "gets it"—handling ambiguity, reasoning about tradeoffs, and solving complex multi-system bugs with creative problem-solving that demonstrates genuine understanding rather than rote responses.

Writing and Content Creation

For written content, Claude maintains its edge. Claude sounds more human right out of the box—its outputs vary more in sentence structure, use transitions more naturally, and avoid the repetitive patterns that make AI text feel robotic. Developer sentiment consistently describes Claude as having the "most human-like writing style."

The Model Families Today

Cost Comparison

The pricing landscape has shifted significantly. Claude Opus 4.5 at $5/$25 per million tokens makes Opus-level capabilities much more accessible than previous versions. GPT-5 at $1.25/$10 remains the most cost-effective flagship option for high-volume work.

For most developers, the sweet spot depends on use case: Claude Opus 4.5's efficiency means it often costs less in practice despite higher per-token pricing (using up to 65% fewer tokens), while GPT-5's raw pricing wins for simpler, high-volume tasks.

Making Your Choice

The emerging consensus: both models are exceptional, and many organizations use them in tandem—Claude for sustained coding tasks and writing, GPT-5 for multimodal work and math-heavy applications. The wise approach is building systems flexible enough to leverage the strengths of each.