Summary
Quick Decision (March 2026)
- Choose Claude Opus if: You do complex coding, long-form writing, or detailed analysis. Opus leads SWE-bench Verified (80.8%), MATH 500 (96.4%), and produces the best instruction-following prose. 200K token context (1M beta).
- Choose ChatGPT if: You need web browsing, image generation, plugins, or fast responses. GPT-5.3 leads Terminal-Bench (77.3%), has the broadest tool ecosystem, and runs at 65-70 tok/s (1,000+ with Spark).
- For API usage: Morph routes between Claude and GPT models automatically, sending each task to the model that handles it best. One endpoint, cross-provider optimization.
These are the two most-used AI assistants. They score within a few points of each other on most benchmarks. The differences show up in specific task types, interaction style, and ecosystem. Most people who try both develop a preference based on how each model thinks, not just what it knows.
Stat Comparison
Claude Opus 4.6
Deep reasoning, writing, and coding
"Highest accuracy on hard tasks. Best writing quality."
ChatGPT (GPT-5.3)
Speed, tools, and integrations
"Broadest tool ecosystem. Fastest responses."
Coding
Both models are strong coders. They lead on different benchmarks because they optimize for different coding patterns.
| Benchmark | Claude Opus 4.6 | ChatGPT (GPT-5.3) | What It Tests |
|---|---|---|---|
| SWE-bench Verified | 80.8% | Not reported | Real GitHub issue resolution |
| SWE-bench Pro | 55.4% | 56.8% | Harder GitHub issues |
| Terminal-Bench 2.0 | 65.4% | 77.3% | Terminal agent tasks |
| HumanEval | 97.6% | 98.1% | Function-level code gen |
Claude: Deeper Reasoning on Hard Problems
Opus leads SWE-bench Verified (80.8%). On SWE-bench Pro, Codex 5.3 edges ahead at 56.8% vs Opus's 55.4%. Both benchmarks test real GitHub issues requiring multi-file understanding, dependency tracking, and test validation. Opus's advantage shows on Verified, where its hidden thinking traces help it reason through complex single-repo problems.
ChatGPT: Faster Execution, Fewer Tokens
GPT-5.3 leads Terminal-Bench 2.0 (77.3% vs 65.4%), a 12-point gap. Terminal-Bench tests terminal agent tasks: compiling code, configuring servers, debugging systems. GPT-5.3 also uses 2-4x fewer tokens per task, making it faster and cheaper for straightforward implementation work.
Coding Summary
For complex multi-file refactoring and reasoning-heavy code tasks, Claude Opus is measurably better. For terminal workflows, implementation speed, and token efficiency, ChatGPT (GPT-5.3) wins. Neither dominates across all coding tasks.
Writing
Writing quality is harder to benchmark than coding. User preferences are consistent enough to draw conclusions.
| Aspect | Claude Opus | ChatGPT |
|---|---|---|
| Prose style | Nuanced, varied sentence structure | Confident, concise, sometimes generic |
| Long-form quality | Strong (maintains coherence over 2,000+ words) | Degrades on longer pieces |
| Instruction following | Strict (follows style, tone, format specs) | Good but drifts on complex prompts |
| Short-form content | Good | Good |
| Creativity | More varied, less predictable | More formulaic, more consistent |
Most writers who use both report preferring Claude for long-form work: essays, reports, technical documentation, creative writing. Claude follows style instructions more precisely and maintains quality over longer outputs. ChatGPT excels at short-form: quick summaries, marketing copy, email drafts where conciseness is the goal.
The difference is most noticeable on repeat interactions. ChatGPT tends to converge on a recognizable "ChatGPT voice" regardless of prompt. Claude adapts more to the style specified in the prompt. If you need output that does not sound AI-generated, Claude gives you more control.
Reasoning
| Benchmark | Claude Opus 4.6 | ChatGPT (GPT-5.3) | What It Tests |
|---|---|---|---|
| MATH 500 | 96.4% | ~91% | Competition-level math |
| GPQA Diamond | 68.4% | ~65% | Graduate-level science |
| MMLU-Pro | ~84% | ~85% | Multi-task language understanding |
| ARC-AGI | ~68% | ~72% | Abstract reasoning patterns |
Opus leads on math (96.4% vs ~91% MATH 500) and science (68.4% vs ~65% GPQA Diamond). These gaps reflect the hidden thinking traces: Opus spends more compute per token on internal reasoning. ChatGPT has a slight edge on MMLU-Pro (general knowledge) and ARC-AGI (abstract pattern recognition).
For tasks requiring step-by-step logical deduction, proof construction, or complex analysis, Opus is measurably stronger. For broad knowledge questions and quick analytical tasks, they are comparable.
Features and Integrations
| Feature | Claude Opus | ChatGPT |
|---|---|---|
| Web browsing | Available (limited) | Deep integration |
| Image generation | No | Yes (DALL-E) |
| Image understanding | Yes | Yes |
| File upload/analysis | Yes | Yes |
| Plugins/extensions | MCP (API only) | GPT Store, plugins |
| API access | $5/$25 per 1M tokens | ~$2-5/$10-15 per 1M tokens |
| Context window | 200K (1M beta) | 256K (GPT-5.3) |
| Coding agent | Claude Code (terminal) | Codex (in ChatGPT) |
ChatGPT has the broader feature set: native web browsing, image generation, a plugin marketplace, and the GPT Store. Claude is more focused: better coding, better writing, better reasoning, with fewer surrounding features. If you need an all-in-one AI assistant that browses, generates images, and connects to third-party services, ChatGPT covers more ground. If you need the highest quality on text-based tasks, Claude wins.
Pricing
| Tier | Claude (Anthropic) | ChatGPT (OpenAI) |
|---|---|---|
| Free | Claude.ai Free (limited Opus) | ChatGPT Free (GPT-5.3 limited) |
| $8/month | N/A | ChatGPT Go |
| $20/month | Claude Pro | ChatGPT Plus |
| $100/month | Claude Max 5x | N/A |
| $200/month | Claude Max 20x | ChatGPT Pro |
| API (input/output) | $5 / $25 per 1M tokens | ~$2-5 / $10-15 per 1M tokens |
At $20/month, both offer comparable value for casual to moderate use. ChatGPT has a cheaper $8/month Go tier. Claude has a $100/month tier (Max 5x) that OpenAI does not match. At the $200/month premium tier, both offer maximum model access. API pricing varies by model variant, with OpenAI generally cheaper per token.
When to Use Claude Opus
Complex Coding Tasks
Multi-file refactoring, large codebase reasoning, architecture design. Opus scores 80.8% SWE-bench Verified and 55.4% SWE-bench Pro. Its hidden thinking traces catch interdependencies that faster models miss. Claude Code provides a terminal-native coding agent.
Long-Form Writing
Reports, technical documentation, essays, creative writing. Claude maintains quality over 2,000+ words, follows style instructions precisely, and produces less formulaic prose. If your writing needs to not sound AI-generated, Claude gives you more control.
Mathematical and Scientific Reasoning
Opus scores 96.4% on MATH 500 (vs ~91% for GPT-5.3) and 68.4% on GPQA Diamond. For proofs, algorithm analysis, numerical correctness, and scientific reasoning, Opus's extra compute per token produces better answers.
Precise Instruction Following
When your prompt specifies exact output format, style, tone, length, or structure, Opus adheres more consistently. It drifts less from complex multi-part instructions. For automated pipelines that depend on structured output, this matters.
When to Use ChatGPT
Web Research and Browsing
ChatGPT's web browsing is deeply integrated. Ask a question, it searches, synthesizes, and cites sources. For research tasks requiring current information, competitive analysis, or fact-checking, ChatGPT's browsing provides immediate utility.
Terminal and DevOps Workflows
GPT-5.3 scores 77.3% on Terminal-Bench 2.0 (vs Opus's 65.4%). For shell scripting, server configuration, CI/CD setup, and infrastructure automation, ChatGPT's Codex variant is measurably better.
Image Generation and Visual Tasks
ChatGPT generates images via DALL-E. Claude does not generate images. For any workflow involving creating visual content, mockups, diagrams, or illustrations, ChatGPT is the only option between the two.
Quick Answers and Speed
GPT-5.3 runs at 65-70 tok/s (1,000+ with Spark) vs Opus at 46 tok/s with 7.83s TTFT. For quick lookups, short tasks, and interactive conversations where latency matters, ChatGPT responds noticeably faster.
Frequently Asked Questions
Is Claude Opus or ChatGPT better?
Neither is universally better. Claude Opus leads on coding (80.8% SWE-bench), writing quality, and mathematical reasoning (96.4% MATH 500). ChatGPT leads on terminal tasks (77.3% Terminal-Bench), tool ecosystem (web browsing, image generation), and speed. Choose based on your primary use case.
Which is better for coding?
Claude Opus for complex reasoning and multi-file refactoring (80.8% SWE-bench Verified, 55.4% Pro). ChatGPT for terminal workflows and fast implementation (77.3% Terminal-Bench, 2-4x fewer tokens). Most developers benefit from access to both.
Which is better for writing?
Claude for long-form and instruction-following. It produces more varied prose and follows style specs more precisely. ChatGPT for short-form, concise content. The difference is most noticeable on pieces longer than 1,000 words.
How much does each cost?
Both offer $20/month subscriptions. ChatGPT has a cheaper $8/month Go tier. Claude has a $100/month Max 5x tier. Both have $200/month premium tiers. API pricing varies: Opus at $5/$25, GPT-5.3 at roughly $2-5/$10-15 per million tokens.
Can ChatGPT browse the web?
Yes, natively integrated. Claude has limited web search on claude.ai. For research requiring current information, ChatGPT's browsing is more capable.
Can I use both through one API?
Morph's API routes between Claude and GPT models automatically. It sends each task to the optimal model based on complexity. One endpoint, cross-provider optimization, lower cost than using either model exclusively.
Route Between Claude and GPT Models Automatically
Morph's API selects the optimal model per task. Complex reasoning goes to Claude Opus. Fast execution goes to GPT. One endpoint, best-of-both-worlds performance.