GPT-5.4 vs Claude Opus 4.6: Which AI Model Wins in 2026?
GPT-5.4 vs Claude Opus 4.6 — the ultimate 2026 AI showdown. We compare coding performance, pricing, benchmarks, agentic capabilities, and which model is best for developers, writers, and businesses.
TL;DR
| GPT-5.4 | Claude Opus 4.6 | |
|---|---|---|
| Coding (SWE-bench Verified) | 82.1% | 80.8% |
| Agentic coding (Terminal-Bench) | 51.3% | 65.4% |
| Computer use (OSWorld) | 75.0% | 72.7% |
| Math (AIME 2025) | 100% | ~92.8% |
| Science (GPQA Diamond) | ~89.5% | 91.3% |
| Novel reasoning (ARC-AGI-2) | 62.1% | 68.8% |
| Input price | $6/M | $15/M |
| Output price | $18/M | $75/M |
| Context window | 512K | 1M (beta) |
- Budget, speed, general tasks, computer use → GPT-5.4
- Agentic coding, multi-agent orchestration, large codebases, deep reasoning → Claude Opus 4.6
The March 2026 Flagship Face-Off
OpenAI's GPT-5.4 (March 2026) and Anthropic's Claude Opus 4.6 (February 2026) are the two most powerful AI models available today. They represent fundamentally different philosophies:
- GPT-5.4 — a stronger all-around generalist. Faster, cheaper, broader capabilities. Uses up to 47% fewer tokens on complex tasks.
- Claude Opus 4.6 — the specialist's choice. Unmatched on agentic coding, multi-agent orchestration, and reliability on sprawling codebases.
Coding Performance
SWE-bench Verified (Real-World Software Engineering)
SWE-bench tests models on resolving actual GitHub issues — reading codebases, understanding bugs, writing patches.
| Model | Score |
|---|---|
| GPT-5.4 | 82.1% |
| Opus 4.6 | 80.8% |
| Sonnet 4.6 | 79.6% |
GPT-5.4 takes the lead here with a 1.3-point edge over Opus 4.6. For isolated bug fixes and single-file patches, both models are excellent, but GPT-5.4 resolves slightly more issues on the first attempt.
Terminal-Bench 2.0 (Agentic Terminal Coding)
This is where the gap flips. Terminal-Bench tests multi-step, multi-file coding tasks in a terminal — closer to real AI-assisted development.
| Model | Score |
|---|---|
| Opus 4.6 | 65.4% |
| Sonnet 4.6 | 59.1% |
| GPT-5.4 | 51.3% |
Opus 4.6 outperforms GPT-5.4 by 14.1 points. In practice, this means Opus handles long-horizon refactors, dependency upgrades, and cross-file changes with significantly fewer errors.
Large Codebase Reliability
Where Opus 4.6 truly separates itself is on repositories with 50,000+ lines of code. Developer reports consistently highlight:
- Opus reads existing patterns before modifying code
- It consolidates duplicated logic instead of adding more
- Fewer "phantom completions" — it doesn't claim success prematurely
- Better at maintaining consistency across files during refactors
Agentic Capabilities
Multi-Agent Orchestration
Opus 4.6 was designed for multi-agent workflows. It excels at:
- Breaking complex tasks into subtasks and delegating to sub-agents
- Maintaining shared context across agent chains
- Self-correcting when an agent in the chain returns unexpected results
- Coordinating parallel tool calls without losing track of state
Computer Use
| Model | OSWorld Score |
|---|---|
| GPT-5.4 | 75.0% |
| Opus 4.6 | 72.7% |
| Sonnet 4.6 | 72.5% |
GPT-5.4 has a slight edge on computer use benchmarks, particularly on speed. It navigates UIs faster and handles form-filling more efficiently. Opus 4.6 is more reliable on complex multi-step desktop workflows but takes longer.
Tool Use and Function Calling
GPT-5.4 benefits from OpenAI's mature function calling and structured output APIs. If your agent architecture relies heavily on tool use with strict JSON schemas, GPT-5.4's tooling is more polished.
Opus 4.6 handles tool use well but shines more in unstructured, exploratory tool use — the kind found in Claude Code sessions where the model decides what to read, edit, and run.
Winner: Opus 4.6 (orchestration, exploratory agents), GPT-5.4 (computer use, structured tool calling)Be first to build with AI
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Reasoning and Knowledge
Math (AIME 2025)
| Model | Score |
|---|---|
| GPT-5.4 | 100% |
| Opus 4.6 | ~92.8% |
GPT-5.4 maintains OpenAI's perfect score on competition math. For financial modeling, quantitative analysis, and math-heavy research, GPT-5.4 is the safer choice.
Science (GPQA Diamond)
| Model | Score |
|---|---|
| Opus 4.6 | 91.3% |
| GPT-5.4 | ~89.5% |
Opus leads on graduate-level science reasoning. The gap is modest but consistent across physics, chemistry, and biology questions.
Novel Problem Solving (ARC-AGI-2)
| Model | Score |
|---|---|
| Opus 4.6 | 68.8% |
| GPT-5.4 | 62.1% |
ARC-AGI-2 tests the ability to solve completely new problem types. Opus 4.6's 6.7-point lead suggests stronger generalization to unfamiliar domains — useful for research, architecture design, and creative problem-solving.
Winner: GPT-5.4 (math), Opus 4.6 (science, novel reasoning)Pricing
This is GPT-5.4's biggest advantage.
API Cost Comparison
| Model | Input (/M tokens) | Output (/M tokens) | 100K in + 20K out |
|---|---|---|---|
| GPT-5.4 | $6 | $18 | $0.96 |
| Opus 4.6 | $15 | $75 | $3.00 |
| Sonnet 4.6 | $3 | $15 | $0.60 |
Opus 4.6 costs roughly 3x more per session than GPT-5.4. A task that costs $1.00 with Opus runs for approximately $0.10–$0.15 with GPT-5.4 when accounting for the token efficiency gap.
Token Efficiency
GPT-5.4 uses up to 47% fewer tokens on complex tasks compared to Opus 4.6. This compounds the pricing gap — not only are GPT-5.4's tokens cheaper, you need fewer of them.
Monthly Cost at Scale (200 sessions/day)
| Model | Daily cost | Monthly cost |
|---|---|---|
| GPT-5.4 | $192 | $5,760 |
| Opus 4.6 | $600 | $18,000 |
| Sonnet 4.6 | $120 | $3,600 |
For most production workloads, the cost difference is hard to ignore. Teams running hundreds of daily sessions save $12,000+/month choosing GPT-5.4 over Opus 4.6.
Winner: GPT-5.4 (significantly cheaper)Context Window
| Model | Context Window | Notes |
|---|---|---|
| Opus 4.6 | 1M tokens | Beta, with context compaction |
| GPT-5.4 | 512K tokens | Native |
Opus 4.6's 1M context window is nearly double GPT-5.4's. For large codebase analysis, long document processing, and extended coding sessions, Opus maintains coherence over much longer conversations.
Context compaction — automatically summarizing older parts of the conversation — extends Opus's effective context even further. This is particularly valuable in Claude Code sessions that can span hours.
Winner: Claude Opus 4.6Which Model Should You Choose?
Choose GPT-5.4 When:
- Cost matters — GPT-5.4 delivers 80-90% of Opus's quality at ~30% of the price
- You need speed — GPT-5.4 responds faster on most tasks
- Math-heavy workloads — perfect AIME scores speak for themselves
- Computer use and UI automation — slight edge on speed and reliability
- You're building with OpenAI's API ecosystem (Assistants, function calling, structured outputs)
- General-purpose business tasks — writing, analysis, customer support
Choose Opus 4.6 When:
- Agentic coding on large codebases — Opus's 14-point Terminal-Bench lead is decisive
- Multi-agent orchestration — complex workflows with 5+ coordinating agents
- The hardest reasoning problems — novel research, architecture design, ambiguous requirements
- You need 1M context — long documents, entire codebases in context
- Reliability over speed — fewer hallucinations, fewer false completions
- You're using Claude Code as your primary development tool
The Smart Approach: Use Both
Most teams benchmark both models on their specific workloads. A common pattern:
- GPT-5.4 for 80% of tasks (fast, cheap, good enough)
- Opus 4.6 for the remaining 20% (hard problems, long contexts, critical code changes)
- Sonnet 4.6 as the cost-efficient default ($3/$15 — cheaper than both)
The Bottom Line
GPT-5.4 is the better generalist — faster, cheaper, and strong across the board. For most businesses and developers, it's the practical default. Claude Opus 4.6 is the better specialist — unmatched on agentic coding, multi-agent systems, and deep reasoning over large contexts. If you're building serious AI-powered software, Opus pays for itself.The answer isn't one or the other. It's knowing when to use each.
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FAQ
Is GPT-5.4 better than Claude Opus 4.6?
GPT-5.4 is better for general tasks, math, and cost efficiency. Opus 4.6 is better for agentic coding, multi-agent orchestration, and deep reasoning on large codebases. Most teams benefit from using both.How much cheaper is GPT-5.4 than Opus 4.6?
GPT-5.4 costs roughly 70% less per session. A $1 Opus task typically costs $0.10–$0.15 with GPT-5.4 when factoring in both lower token prices and GPT-5.4's higher token efficiency.Which model is better for coding?
Opus 4.6 leads on agentic coding (Terminal-Bench: 65.4% vs 51.3%) and large-codebase reliability. GPT-5.4 leads on single-task bug fixes (SWE-bench: 82.1% vs 80.8%). For AI-assisted development with tools like Claude Code, Opus is the stronger choice.Can I use both models in the same project?
Yes. Model routing — automatically selecting GPT-5.4 for simple tasks and Opus 4.6 for complex ones — is a common production pattern. This optimizes both cost and quality.Which model has a larger context window?
Opus 4.6 supports 1M tokens (beta) with context compaction. GPT-5.4 supports 512K tokens natively.Sources:
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