Claude Haiku vs Sonnet vs Opus: Which Model Should You Use?

Anthropic offers three Claude models with distinct tradeoffs between speed, quality, and cost. Choosing the right model for each task can reduce your costs by 5-10x without sacrificing output quality. This guide breaks down the practical differences between Claude Haiku 4.5, Sonnet 4.6, and Opus 4.6 based on real-world usage patterns.

The Three Models at a Glance

MTok = million tokens. One token is roughly 3/4 of a word. A typical message (prompt plus response) might use 500-2,000 tokens total.

Claude Haiku 4.5: The Speed Specialist

Haiku 4.5 is Anthropic's fastest model and the most cost-effective option for straightforward tasks. It processes requests 3-4x faster than Opus and costs 5x less per input token.

Where Haiku Excels

Quick lookups and simple questions. When you need a fast answer to a factual question, a definition, or a simple explanation, Haiku responds almost instantly. The quality difference between Haiku and Opus on these tasks is negligible.

Text transformation. Reformatting data, converting between formats (JSON to CSV, for example), fixing grammar, and adjusting tone are tasks where Haiku matches the larger models at a fraction of the cost.

Summarization of short content. For articles under 2,000 words, Haiku produces summaries that are nearly identical in quality to Sonnet's output. The speed advantage means you get results in under a second.

High-volume processing. If you are processing dozens or hundreds of items (emails, support tickets, product descriptions), Haiku's low cost makes batch processing economically viable. Processing 1,000 short emails with Haiku costs roughly $0.50-1.00 in credits, versus $2.50-5.00 with Sonnet.

Where Haiku Falls Short

Haiku struggles with multi-step reasoning, nuanced analysis, and tasks that require holding many pieces of context in mind simultaneously. It also tends to give shorter, less detailed responses, which can be a drawback when you need comprehensive output.

Cost Example

A typical Haiku conversation with 800 input tokens and 400 output tokens:

• Input: (800 / 1,000,000) x $1.00 = $0.0008
• Output: (400 / 1,000,000) x $5.00 = $0.002
• Total: $0.0028 per message
• With Prophet's 20% markup: roughly 1 credit (1 cent) per message

At this rate, the Prophet Pro plan ($9.99/month for $11 in credits) supports roughly 1,100 Haiku messages per month, or about 36 per day.

Claude Sonnet 4.6: The Daily Driver

Sonnet 4.6 occupies the middle ground and is the model most users should default to. It offers a strong balance between response quality, speed, and cost. For most professional tasks, Sonnet produces output that is indistinguishable from Opus at 40% lower cost.

Where Sonnet Excels

Code generation and review. Sonnet 4.6 writes clean, well-structured code with appropriate error handling. It understands modern frameworks and follows current best practices. For code review, it identifies bugs, security issues, and performance problems with high accuracy.

Document analysis. Sonnet handles 5,000-15,000 word documents well, extracting key information, identifying themes, and answering specific questions about the content. It maintains context across long documents better than Haiku while responding faster than Opus.

Professional writing. Emails, reports, documentation, and blog content (like this article) are Sonnet's sweet spot. The writing is clear, well-organized, and professional without requiring extensive editing.

Web page interaction. When using browser automation features in tools like Prophet, Sonnet provides the best balance between understanding page structure and responding quickly. It parses accessibility trees accurately and generates reliable action sequences.

Where Sonnet Falls Short

Sonnet occasionally oversimplifies complex analytical tasks. When comparing multiple options with subtle tradeoffs or analyzing documents with internal contradictions, it may miss nuances that Opus catches. For tasks requiring genuine intellectual depth, the upgrade to Opus is worth the cost.

Cost Example

A typical Sonnet conversation with 1,200 input tokens and 600 output tokens:

• Input: (1,200 / 1,000,000) x $3.00 = $0.0036
• Output: (600 / 1,000,000) x $15.00 = $0.009
• Total: $0.0126 per message
• With Prophet's 20% markup: roughly 2 credits (2 cents) per message

The Prophet Pro plan supports roughly 550 Sonnet messages per month, or about 18 per day. The Premium plan ($29.99/month for $35 in credits) supports roughly 1,750 messages, or 58 per day.

Claude Opus 4.6: The Deep Thinker

Opus 4.6 is Anthropic's most capable model and the right choice when quality matters more than speed or cost. It handles complex reasoning, long-context analysis, and nuanced tasks that the smaller models cannot match.

Where Opus Excels

Complex multi-step reasoning. Mathematical proofs, legal analysis, strategic planning, and any task that requires holding multiple interrelated concepts in mind simultaneously. Opus makes fewer logical errors on these tasks than Sonnet and significantly fewer than Haiku.

Very long documents. For documents exceeding 15,000 words, Opus maintains coherent understanding across the entire text. It identifies cross-references, internal contradictions, and thematic patterns that Sonnet may miss in documents of this length.

Nuanced writing. Academic papers, technical specifications, and content that requires precise language benefit from Opus's attention to detail. It is less likely to make claims that are approximately true but technically incorrect.

Difficult code problems. Architecture decisions, complex debugging sessions, and performance optimization benefit from Opus's deeper reasoning. When the problem is not straightforward, the quality difference between Sonnet and Opus becomes apparent.

Research and analysis. Comparing competing interpretations, evaluating evidence quality, and synthesizing information from multiple sources are tasks where Opus consistently produces more thorough and accurate output.

Where Opus May Be Overkill

Simple questions, basic text formatting, short summaries, and routine coding tasks do not benefit meaningfully from Opus's additional capability. Using Opus for these tasks is like driving a sports car to the corner store: it works, but you are paying for performance you do not need.

Cost Example

A typical Opus conversation with 2,000 input tokens and 1,000 output tokens:

• Input: (2,000 / 1,000,000) x $5.00 = $0.01
• Output: (1,000 / 1,000,000) x $25.00 = $0.025
• Total: $0.035 per message
• With Prophet's 20% markup: roughly 5 credits (5 cents) per message

The Prophet Premium plan supports roughly 700 Opus messages per month, or about 23 per day. The Ultra plan ($59.99/month for $70 in credits) supports roughly 1,400 messages, or 47 per day.

A Practical Model Selection Strategy

Rather than picking one model for all tasks, the most cost-effective approach is to match the model to the task:

Use Haiku When:

• The task is straightforward with an obvious answer
• You need a fast response (under 1 second)
• You are processing items in bulk
• The output will be short (a few sentences)
• You are brainstorming and need many quick iterations

Use Sonnet When:

• You are writing professional content (emails, reports, documentation)
• You need code generated or reviewed
• You are analyzing a document under 15,000 words
• You want browser automation via tools like Prophet
• You are unsure which model to use (Sonnet is the safe default)

Use Opus When:

• The task requires multi-step reasoning or complex analysis
• You are working with very long documents (over 15,000 words)
• Precision and nuance matter more than speed
• You are making a high-stakes decision based on the output
• Sonnet's response was not thorough enough on a first attempt

Cost Comparison Across Usage Levels

The table below shows estimated monthly costs on Prophet's platform for different usage levels, assuming average message lengths:

A mixed strategy — using Haiku for 60% of messages, Sonnet for 30%, and Opus for 10% — reduces the moderate user's cost from $18/month (all Sonnet) to roughly $11/month, fitting comfortably within Prophet's Pro plan.

How to Switch Models in Prophet

Prophet makes model switching simple. In the side panel, you can select your model from a dropdown before sending each message. The model choice persists until you change it, so you can set Sonnet as your default and switch to Haiku or Opus when the task calls for it. Each message in your chat history shows which model generated it, so you can compare output quality across models on the same conversation.

Bottom Line

Start with Sonnet for everything. It handles 80% of tasks well and costs 40% less than Opus. When you notice a response that feels shallow or misses nuance, switch to Opus for that specific conversation. When you are doing something simple and want a faster response, drop to Haiku. This adaptive approach maximizes quality while minimizing cost, and Prophet's per-message pricing makes the switching cost zero.