Claude Opus vs. Sonnet vs. Haiku: A Cost Guide

Picking the right Claude model is one of the biggest cost levers you have - bigger than most prompt tuning. A Claude model cost comparison across Opus, Sonnet, and Haiku shows differences of an order of magnitude per token, which means the same feature can cost pennies or dollars depending purely on which tier you default to.

The three tiers, in cost terms

• Opus - the most capable and the most expensive. Reserve it for genuinely hard reasoning, long-horizon agents, and tasks where a wrong answer is costly.
• Sonnet - the balanced middle. Strong quality at a fraction of Opus pricing; the right default for most production features.
• Haiku - the fastest and cheapest. Ideal for classification, extraction, routing, and high-volume simple calls.

Price the workload, not the model

A headline per-million-token rate doesn't tell you your bill - your token volume does. A cheap model called a million times can cost more than an expensive one called a thousand times. Estimate real cost by combining the rate with your actual input/output token counts, using the method in how LLM API pricing works.

Model routing: cheap by default, expensive on demand

The highest-leverage pattern is to route each request to the cheapest model that can handle it, and only escalate when needed:

// Triage cheap, escalate only when the task warrants it.
const model =
  task.complexity === "high" ? "claude-opus-4-8" :
  task.complexity === "low"  ? "claude-haiku-4-5" :
                               "claude-sonnet-5";

const res = await guard.messages.create({ model, max_tokens, messages });

Even a crude classifier that sends obvious cases to Haiku and hard ones to Sonnet can cut spend substantially without a quality hit users notice.

Layer caching on top

Model choice sets the base rate; prompt caching discounts the repeated parts of your input on whichever model you land on. The two compound. To know which model each feature is actually using - and whether a silent upgrade crept in - watch it with real cost monitoring.