ChatGPT vs Claude 3.5 Sonnet: Which AI Is Actually Smarter in 2024?

Two AI giants. One question: which one should power your workflow? ChatGPT (powered by GPT-4o) and Claude 3.5 Sonnet from Anthropic are currently the most capable AI assistants available — and the gap between them is narrower than ever. But "smarter" depends heavily on what you're asking them to do.

This comparison breaks down both models across the areas that matter most to creators, marketers, developers, and business owners — with real benchmark data, honest pros and cons, and a clear recommendation at the end.

The Benchmark Data: How Both AIs Have Evolved

To understand how far these models have come, here's a composite benchmark performance trend combining scores across MMLU (general knowledge), HumanEval (coding), and GSM8K (math reasoning). The index is normalised to GPT-3.5's launch performance in November 2022 as a baseline of 100.

Date	Composite Benchmark Score (Index)
Nov 2022	100
Jan 2023	105
Jun 2023	115
Jan 2024	128
Mar 2024	142
Jun 2024	155
Oct 2024	168

Source: AI benchmark aggregation across MMLU, HumanEval, and GSM8K datasets. Scores represent top-performing model at each date across both platforms.

A 68% improvement in under two years is staggering. What this table doesn't show is that Claude 3.5 Sonnet has been responsible for pushing many of those recent jumps — especially in coding and reasoning categories.

Head-to-Head Comparison: Key Capabilities

Capability	ChatGPT (GPT-4o)	Claude 3.5 Sonnet	Winner
Coding & Debugging	Excellent	Best-in-class	Claude 3.5
Long-form Writing	Strong, occasionally verbose	Natural, concise tone	Claude 3.5
Multimodal (Images/Vision)	Full image analysis & generation	Image analysis only	ChatGPT
Context Window	128K tokens	200K tokens	Claude 3.5
Plugin/API Ecosystem	Extensive integrations	Growing but limited	ChatGPT
Math & Reasoning	Very strong (o1 model available)	Strong	ChatGPT (with o1)
Instruction Following	Good, can drift on long tasks	Precise, stays on task	Claude 3.5
Free Tier	GPT-4o with limits	Claude 3.5 with limits	Tie
Pricing (Pro)	$20/month	$20/month	Tie

Writing Quality: Does Claude Actually Sound More Human?

For content creators and marketers, this is often the deciding factor. Claude 3.5 Sonnet consistently produces prose that feels less mechanical. It avoids ChatGPT's occasional tendency to over-explain, pad paragraphs, or default to bullet lists when flowing prose would serve better.

That said, ChatGPT is no slouch. With the right prompting strategy — something we cover extensively in our Best ChatGPT Prompts for Marketing Professionals guide — you can coax exceptional copy from GPT-4o. The difference is that Claude often gets there faster with less prompt engineering.

Coding: Where Claude 3.5 Sonnet Pulls Ahead

On HumanEval benchmarks, Claude 3.5 Sonnet scores around 92% — higher than GPT-4o's approximately 90.2%. In practice, this translates to fewer hallucinated function calls, better understanding of complex codebases, and more accurate debugging suggestions.

For developers who rely on AI daily, Claude's 200K token context window is also a game-changer — you can paste an entire codebase and get coherent, context-aware answers. If you're building automation workflows, check out our guide to connecting ChatGPT to Google Sheets via API — many of the same principles apply when using Claude through its API.

Accuracy and Hallucinations: Which AI Makes Fewer Mistakes?

Both models hallucinate. Anyone telling you otherwise is selling something. However, Claude 3.5 Sonnet tends to be more likely to say "I don't know" rather than confidently fabricate an answer — a behaviour Anthropic has deliberately trained into it through its Constitutional AI approach.

ChatGPT has improved significantly in this area too, but hallucination remains a real concern in high-stakes use cases. We've written a detailed breakdown of why ChatGPT still hallucinates and how to fix it — those strategies largely apply to both models.

Integrations and Ecosystem: ChatGPT Wins Here

If your workflow depends on third-party tools — Zapier, Make, Google Workspace, CRM platforms, or custom APIs — ChatGPT's ecosystem is simply more mature. OpenAI's API is more widely supported, GPTs (custom versions) are shareable, and the plugin infrastructure (while evolving) offers more surface area for automation.

Claude's API is excellent and increasingly supported, but if you're building production-grade AI automations today, ChatGPT remains the safer choice for integration depth. See our comparison of ChatGPT Plugins vs GPT-4 Code Interpreter for a deeper look at what's possible.

Which One Should You Actually Use?

Choose Claude 3.5 Sonnet if you:

• Write long-form content and want a more natural, editorial voice
• Work with large documents, codebases, or research papers
• Want fewer hallucinations and more honest "I don't know" responses
• Are a developer who needs precise instruction-following on complex tasks

Choose ChatGPT (GPT-4o) if you:

• Need image generation alongside text (DALL-E integration)
• Rely on third-party integrations and automation pipelines
• Want access to advanced reasoning through the o1 model
• Build custom GPTs or need a wider plugin ecosystem

The honest answer? Power users should have both. At $20/month each, using them in tandem — Claude for writing and research, ChatGPT for automation and multimodal tasks — delivers more value than picking one and ignoring the other. You can also explore how free vs paid AI writing tools compare if budget is a concern.