Question 1

How much does GPT-5.5 cost?

Accepted Answer

OpenAI launched GPT-5.5 on April 23, 2026 at $5.00 per 1 million input tokens and $30.00 per 1 million output tokens, with a 1 million token context window. That's twice the price of GPT-5.4 ($2.50 input, $15.00 output). GPT-5.5 Pro costs $30.00 input and $180.00 output per 1 million tokens. At 1,000 API calls per day with 1,000 input and 500 output tokens each, GPT-5.5 runs about $600 a month, compared to $300 on GPT-5.4.

Question 2

What is a token in AI?

Accepted Answer

A token is a chunk of text an AI model processes, roughly 4 characters or three-quarters of a word in English. 'Hello, how are you?' is about 6 tokens. AI providers charge per token, not per word or character.

Question 3

Why do output tokens cost more than input?

Accepted Answer

Generating output requires a full forward pass through the model for each token produced. Reading input is faster. Output tokens typically cost 3-10x more than input tokens depending on the model.

Question 4

What's the cheapest AI model right now?

Accepted Answer

The two cheapest paid options right now are Google's Gemini 2.0 Flash-Lite ($0.075 input / $0.30 output per 1M tokens) and Llama 3.2 3B ($0.06/$0.06). For completely free usage, Meta's Llama models are open-source. You run them yourself with no per-token charges.

Question 5

What is prompt caching and how much does it save?

Accepted Answer

Prompt caching lets AI providers reuse previously processed instructions. Cached input tokens cost 90% less on Anthropic and OpenAI models. Use the cache rate slider in the calculator to see projected savings at your call volume.

Question 6

What is model routing and how does it save money?

Accepted Answer

Model routing means sending simple tasks (classification, yes/no, formatting) to cheap models like GPT-4o mini or Gemini Flash, while reserving expensive models only for complex reasoning tasks. The Routing Optimizer tab calculates your exact savings based on your task mix.

Question 7

How accurate is this token counter?

Accepted Answer

The token counter uses the standard approximation of 4 characters per token, accurate within 5-10% for English text. For exact counts, use OpenAI's tiktoken or Anthropic's token counter directly.

Question 8

Who is this calculator for?

Accepted Answer

QuantaCost is built for developers and teams making direct AI API calls: building apps, chatbots, or internal tools powered by OpenAI, Anthropic, Google, or other providers. If you have a flat monthly subscription like ChatGPT Plus, you pay a fixed fee and these token costs don't apply to you.

Question 9

Which AI model should I use?

Accepted Answer

It depends on what you're building, how much quality you need, and how many calls you'll make. QuantaCost has a free 30-second quiz at /quiz that asks four questions (use case, cost vs quality priority, call volume, and special needs) and recommends a top pick plus two alternatives from 38 models across OpenAI, Anthropic, Google, xAI, DeepSeek, Mistral, and Meta.

QuantaCost: AI API Cost Calculator

Tools

Latest guides

More