---
title: "Choosing an AI Model: Haiku, Sonnet, Opus, GPT and Gemini Compared"
description: "How to choose between Claude Haiku, Sonnet and Opus, OpenAI GPT and Gemini: model tiers, honest benchmarks, pricing and where to get strong models cheaply."
type: "article"
locale: "en"
category: "Tools"
canonical: "https://agenticschool.dev/knowledge/choosing-an-ai-model"
datePublished: "2026-06-12"
dateModified: "2026-06-12"
---

# Choosing an AI Model: Haiku, Sonnet, Opus, GPT and Gemini Compared

- Category: Tools
- Reading time: 9 min
- Published: 2026-06-12
- Updated: 2026-06-12
- Keywords: AI model, Claude, GPT, Gemini, OpenRouter, benchmarks
- Canonical URL: https://agenticschool.dev/knowledge/choosing-an-ai-model
- Locale: en

> How to choose between Claude Haiku, Sonnet and Opus, OpenAI GPT and Gemini: model tiers, honest benchmarks, pricing and where to get strong models cheaply.

There is no single best AI model, only the right model for a task and a budget. Every provider ships a family of models in tiers: small and fast, mid and balanced, large and smart. Once you see the tiers instead of the brand names, choosing becomes simple. This guide maps the 2026 landscape, explains how to read benchmarks without being fooled, and shows where to get strong models cheaply or for free.

## Think in tiers, not brands

Forget brand loyalty and think in tiers. Small models are fast and cheap, great for classification, extraction, simple rewrites and high-volume jobs. Mid models are the balanced workhorse for most real coding and writing. Large models are slower and pricier but reason far better on genuinely hard problems. Almost every provider mirrors this structure, so once you internalise it you can place any new model instantly from its spec and price.

## How the families line up

Claude offers Haiku (small), Sonnet (mid) and Opus (large). OpenAI GPT and Google Gemini have equivalent small, mid and large tiers. The rule of thumb is to start one tier lower than you think you need and only move up if the output is genuinely not good enough. Using a flagship model to reformat a list is like hiring a surgeon to apply a plaster.

## Reading benchmarks honestly

Benchmarks are useful and also routinely misleading. A model can top a coding benchmark and still feel worse in your actual project, because benchmarks measure narrow tasks under ideal conditions that providers optimise hard for. Treat them as a rough filter, not a verdict. The only benchmark that matters is your own: take three real tasks from your work, run them through two or three models, and judge the output yourself, paying attention to consistency rather than peak performance.

## Pricing and routing by difficulty

Price is quoted per million input and output tokens, and the spread between tiers is large, often ten times or more. Because output costs several times more than input, verbose models and chatty prompts cost more than you expect. The practical move is to route by difficulty: a cheap model for the easy majority of calls, an expensive model only for the hard minority. On a workflow at scale this single decision often matters more than which provider you chose.

## Getting strong models cheaply or free

You do not have to pay full price to start. OpenRouter gives you one account and key to access almost every model through a single endpoint, with transparent pricing and easy switching, which is ideal for comparing models. Google routinely offers generous free credits through its AI Studio, a genuinely strong low-cost way to get a capable model. Most providers also offer free trial usage you can spend deliberately on your own three-task benchmark.

## FAQ

### Which model is best for beginners?

There is no single best model. Start with a mid tier such as Claude Sonnet, GPT mid or Gemini Pro for most work, drop to a small model for simple high-volume tasks, and only reach for a large model on genuinely hard reasoning.

### Should I trust AI benchmarks?

Only as a rough filter. Run your own three real tasks through a few models and judge the output yourself, focusing on consistency. Your tasks are the only benchmark that reflects how a model will actually serve you.

### Where can I get strong models cheaply?

OpenRouter gives access to almost every model through one account with transparent pricing, and Google AI Studio offers generous free Gemini credits. Both let you start strong without committing a large budget.

### Are bigger context models always better?

No. Quality degrades as the context window fills, so a huge-context model with a sloppy prompt often loses to a mid model with a tight one. Match the model tier to task difficulty rather than chasing context size.