Grok 4.20, GPT-5.4, and Claude Opus 4.6 are the three most powerful AI models available right now. If you're choosing one for coding, research, or building AI agents, this comparison breaks down exactly where each model wins — and where it falls short.
All three launched between February and March 2026. Each takes a different approach to the frontier: xAI bets on massive context and multi-agent orchestration, OpenAI pushes computer use and developer tooling, and Anthropic doubles down on reliability and autonomous operation. Here's how they actually stack up.
Quick Verdict
- Best for massive context: Grok 4.20 (2M tokens, double the competition)
- Best for coding: Claude Opus 4.6 (79.2% SWE-bench Thinking, 80.8% Verified)
- Best for computer use: GPT-5.4 (75% OSWorld, beats human experts)
- Best budget option: Grok 4.20 at $2/$6 per million tokens
- Most expensive: Claude Opus 4.6 at $5/$25 per million tokens
Head-to-Head Comparison
Grok 4.20 | GPT-5.4 2M token context window | 1M token context window $2/M input, $6/M output | $2.50/M input, $15/M output Multi-agent orchestration (16 agents) | Native computer use 828 tokens/sec throughput | Configurable reasoning effort Image + video generation built-in | Spreadsheet and document integration Knowledge cutoff: Nov 2024 | Reduced hallucinations (33% fewer false claims) ::/versus
Pricing Breakdown
Cost matters when you're running thousands of API calls. Here's what each model charges at standard rates:
| Model | Input (per 1M tokens) | Output (per 1M tokens) | Context Window | Budget Tier Available |
|---|---|---|---|---|
| Grok 4.20 | $2.00 | $6.00 | 2,000,000 | Grok 4.1 Fast: $0.20/$0.50 |
| GPT-5.4 | $2.50 | $15.00 | 1,000,000 | GPT-5.4 nano: $0.20/$1.25 |
| Claude Opus 4.6 | $5.00 | $25.00 | 1,000,000 (beta) | Sonnet 4.6: ~$3/$15 |
Grok 4.20 is the clear pricing winner. Output tokens — where the real cost lives — are 60% cheaper than GPT-5.4 and 76% cheaper than Claude Opus 4.6. For high-volume applications, that gap compounds fast.
Benchmark Performance
Benchmarks don't tell the whole story, but they reveal real differences in capability:
| Benchmark | Grok 4.20 | GPT-5.4 | Claude Opus 4.6 | What It Tests |
|---|---|---|---|---|
| SWE-bench Verified | — | ~55% | 80.8% | Real GitHub bug fixes |
| SWE-bench Pro | — | 57.7% | 57.5% | Multi-language coding |
| OSWorld | — | 75.0% | 72.7% | Desktop automation |
| Terminal-Bench 2.0 | — | 75.1% | 65.4% | Agentic terminal coding |
| BigLaw Bench | — | — | 90.2% | Legal reasoning |
| Intelligence Index | 48 | 57.17 | ~55 | Overall reasoning |
| GDPval (Professional) | — | 83% | — | Professional work quality |
Key takeaway: Claude Opus 4.6 dominates code-related benchmarks, especially SWE-bench Verified where it scores 80.8%. GPT-5.4 leads on computer use (OSWorld) and professional workflows. Grok 4.20 focuses less on traditional benchmarks and more on speed and context size.
Coding: Claude Opus 4.6 Wins
For software engineering, Claude Opus 4.6 is the model to beat. Its 80.8% on SWE-bench Verified means it successfully fixes real-world GitHub issues four out of five times. It can operate autonomously for up to seven hours on complex projects, making it ideal for long-running development tasks.
GPT-5.4 is no slouch — it scores 57.7% on the harder SWE-bench Pro benchmark and integrates directly into GitHub Copilot. Its coding DNA comes from GPT-5.3-Codex, which was specifically trained for code.
Grok 4.20 offers a specialized Grok Code Fast model at just $0.20/$1.50, making it the cheapest option for coding workflows that prioritize iteration speed over benchmark accuracy.
Claude Opus 4.6 for Coding
- 80.8% SWE-bench Verified — highest of any model
- 7-hour autonomous operation for complex projects
- Agent teams feature for multi-file refactoring
- 128K max output tokens for large code generation
- Most expensive at $5/$25 per million tokens
- 1M context window requires Tier 4 access
- Terminal-Bench score (65.4%) trails GPT-5.4 ::/proscons
Computer Use and Agentic Tasks: GPT-5.4 Wins
GPT-5.4 is the first general-purpose model with native computer use — it can navigate desktops, click buttons, fill forms, and automate workflows by interpreting screenshots. Its 75% OSWorld score beats human experts (72.4%), which is a genuine milestone.
Claude Opus 4.6 scores 72.7% on OSWorld and has supported computer use since Claude 3.5 Sonnet, but GPT-5.4's native integration is smoother. Grok 4.20 doesn't offer computer use capabilities directly, though its multi-agent system can orchestrate tools that include screen interaction.
Context Window: Grok 4.20 Wins
Grok 4.20's 2 million token context window is double what GPT-5.4 and Claude Opus 4.6 offer. For tasks like analyzing entire codebases, processing long legal documents, or synthesizing research across hundreds of papers, this is a genuine advantage — not a marketing number.
The budget Grok 4.1 Fast model also supports 2M tokens at just $0.20/$0.50, making it absurdly cost-effective for context-heavy workloads.
Speed and Throughput
Grok 4.20's multi-agent system delivers 828 tokens per second in its orchestrated mode, making it one of the fastest frontier models available. The Grok 4.1 Fast variant prioritizes speed over depth for latency-sensitive applications.
GPT-5.4 offers configurable reasoning effort — you can dial down thinking for simple queries and dial up for complex ones, optimizing both speed and cost. Claude Opus 4.6 introduced adaptive thinking in the same vein but tends to favor thoroughness over raw speed.
Multi-Agent and Orchestration
This is where the models diverge most dramatically:
Subscription Access Compared
Not everyone uses the API. Here's what each costs through their respective platforms:
| Platform | Free Tier | Basic | Pro/Power | Enterprise |
|---|---|---|---|---|
| Grok (X/SuperGrok) | Limited via X | $8/mo (X Premium) | $30/mo (SuperGrok) | $300/mo (Heavy) |
| ChatGPT | GPT-5.4 mini | $20/mo (Plus) | $200/mo (Pro) | Custom |
| Claude | Limited Opus 4.6 | $20/mo (Pro) | $100/mo (Max) | $25-150/seat |
Grok offers the cheapest entry at $8/month through X Premium, though full Grok 4.20 access requires SuperGrok Heavy at $300/month. ChatGPT Pro at $200/month gives unlimited GPT-5.4 access including the Pro reasoning tier. Claude Max at $100/month offers the best power-user value.
Who Should Use What
Choose Grok 4.20 if:
- You need massive context windows (2M tokens)
- Budget is a priority — cheapest frontier API pricing
- You're building multi-agent systems natively
- Speed and throughput matter more than benchmark scores
Choose GPT-5.4 if:
- You need computer use and desktop automation
- Professional workflows (documents, spreadsheets) are core
- You want the broadest ecosystem (Copilot, Codex, ChatGPT)
- You need the highest overall intelligence score
Choose Claude Opus 4.6 if:
- Software engineering is your primary use case
- You need autonomous, long-running AI agents
- Reliability and precision matter more than speed
- Legal, security, or enterprise compliance work is involved
The Bottom Line
There's no single "best" model in March 2026 — there's the best model for your use case. Grok 4.20 wins on price and context size. GPT-5.4 wins on computer use and professional workflows. Claude Opus 4.6 wins on coding and autonomous operation.
The real story is how close these three are. A year ago, GPT-4 was the only serious option. Now, three companies are shipping models that trade blows across every benchmark. Competition is driving prices down and capabilities up faster than anyone predicted.
For most developers in 2026, the smart move is to use all three: Grok for context-heavy tasks, GPT-5.4 for automation, and Claude for coding. The API pricing war means you can afford to.
