Claude Opus 4 Token Costs: Context Window vs Cost-Effectiveness [2026]
Claude Opus 4 landed in April 2026 with Anthropic's largest context window to date. At 200k tokens (double Sonnet 4's), it seems like the obvious choice for large codebases. But Opus costs 3-5x more per token than Sonnet. This guide compares all three models and shows which one cuts total costs for typical coding tasks.
Claude model comparison: Context, speed, and cost
| Model | Context Window | Input/Output Cost | Speed | Best For |
|---|---|---|---|---|
| Haiku 4.5 | 100k tokens | Lowest ($0.80/$24 per 1M) | Fastest | Small tasks, quick turnarounds |
| Sonnet 4 | 1M tokens | Mid ($3/$15 per 1M) | Balanced | Most coding tasks, long sessions |
| Opus 4 | 200k tokens | Highest ($15/$45 per 1M) | Slowest | Complex reasoning, research |
What changed with Opus 4?
- ✓Context window: 200k tokens (previously 200k for Opus 3.5, now matches)
- ✓Pricing: Same as Opus 3.5 (expensive per token)
- ✓Performance: Better reasoning on complex problems
- ✓Speed: Slower than Sonnet 4, not suitable for rapid iterations
Cost per coding task: Real numbers
A typical Claude Code session with 20 tool calls across 10 files, lasting 30 minutes:
| Model | Tokens In | Tokens Out | Total Cost |
|---|---|---|---|
| Haiku 4.5 | 120k | 15k | $0.10 |
| Sonnet 4 | 120k | 15k | $0.42 |
| Opus 4 | 120k | 15k | $1.95 |
Opus costs 20x more for the same task. Yes, Opus gives better reasoning on complex problems. But for most coding work—refactoring, debugging, test writing—Sonnet 4 is cheaper and fast enough.
Sonnet 4's 1M token window: Do you really need Opus?
Sonnet 4 recently got bumped to 1M token context (matching Opus). This changes the math. Sonnet can now load entire large codebases in a single session. The only reason to use Opus is if you hit rate limits or need better reasoning on complex problems. For token volume, Sonnet is now the better choice.
When to use each model in Claude Code
- ✓Haiku 4.5: Quick fixes, small scripts, low-stakes tasks. Fastest turnaround.
- ✓Sonnet 4: Most coding work. Balanced speed, cost, and reasoning. 1M token window covers big codebases.
- ✓Opus 4: Complex reasoning, multi-step architecture, when cost is not a factor.
Reduce costs further with Token Limits proxy
Regardless of which model you choose, Token Limits proxy cuts token consumption 60-80% on tool outputs. That same 30-minute session drops from 135k tokens (120k+15k) to 45k tokens. Cost per session: $0.04 (Haiku), $0.18 (Sonnet), $0.81 (Opus).
- Install: npm install -g token-limits
- Start: token-limits start
- In Claude Code: Tools → API URL → http://localhost:4800
- All tool outputs now compressed 60-80%
With Token Limits installed, Haiku becomes viable even for large tasks. And Sonnet becomes almost free.
Cut Opus 4 costs by 80% with Token Limits
Token Limits proxy compresses every grep, file read, and diff automatically. Same results, fraction of the token cost. Works with Haiku, Sonnet, and Opus.
FAQ
Is Opus 4 better for code than Sonnet 4?
Not necessarily. For most coding tasks (refactoring, testing, debugging), Sonnet is equally capable and costs 1/5 as much. Use Opus for complex architectural decisions or research-heavy tasks.
Does Sonnet 4 really have 1M tokens like Opus?
Yes. As of March 2026, Sonnet 4 context window was expanded to 1M tokens (matching Opus). The main difference now is pricing and reasoning quality, not capacity.
Should I use Haiku for coding?
Haiku is fastest and cheapest, but less accurate for complex tasks. It is great for quick fixes and small scripts. For full-featured development, Sonnet is the sweet spot.
Does Token Limits proxy work with all models?
Yes. The proxy compresses tool outputs the same way regardless of model. Works with Haiku, Sonnet, Opus, and any Claude variant.
Can I switch models mid-session in Claude Code?
No. You choose a model when starting a new chat. Switch models by starting a fresh conversation.