How does NumStack calculate AI token costs?

NumStack uses real published pricing from OpenAI, Anthropic, Google, and other AI providers. Enter your typical usage (input tokens, output tokens, requests per day) to see projected monthly costs across all models.

Why do different AI models have different token prices?

Different models have different computational costs. Smaller models like GPT-4o mini or Haiku are cheaper but less capable. Larger models like GPT-4o or Claude Sonnet are more powerful but cost more per token.

How can I reduce my AI API costs?

Use smaller models for simple tasks, cache repeated prompts, trim output length (output tokens cost 3-5x more than input), and batch requests instead of real-time when latency allows.

About NumStack - AI Token Cost Calculator

What NumStack Is

NumStack is a set of free, focused calculators for two kinds of numbers people struggle to estimate: AI infrastructure costs (token pricing, agent workflows, fine-tuning ROI, vector databases, and more) and everyday personal finance (paycheck take-home pay and tax refund estimates). Each calculator does one job well — enter your numbers, get a real, current estimate, no spreadsheet required.

We started with a simple token cost calculator to compare AI API pricing across providers, and expanded from there as it became clear the same "why is this so hard to estimate" problem shows up across AI infrastructure planning and everyday financial questions alike.

The Problem We Solve

When you're building with AI APIs, or just trying to plan your own budget, you run into the same kind of questions:

Which provider or model is cheapest for my actual usage pattern, not a generic benchmark?
How much will this cost at scale once token usage, request volume, or a paycheck changes?
What's the real trade-off between cost and quality, or between take-home pay and deductions?

NumStack answers these in seconds, using current numbers instead of guesswork.

Who Uses NumStack

Startup founders and indie developers building AI products on tight budgets
ML engineers and AI teams comparing model or vendor costs before committing
Students and researchers learning how LLM pricing and economics actually work
CTOs and technical leads planning infrastructure spend
Anyone who wants a quick, honest estimate of their paycheck or tax refund

How Our Pricing Data Works

AI model pricing in the calculators comes from each provider's publicly published rates. We check provider pricing pages regularly and update our model database whenever a provider changes a rate, adds a model, or deprecates one — the current update date is shown at the bottom of the calculators that use it. Pricing changes fairly often across the industry, so we treat every number as a snapshot: always verify current rates with the provider directly before making a spending decision, and use the "Request it" link on the Token Cost calculator if a model you use is missing.

What Makes Us Different

No sign-up required — every calculator works immediately, with nothing to create an account for.
All major AI providers — OpenAI, Anthropic, Google, Meta, Mistral, and more, compared side by side.
Current pricing data — checked regularly and updated as providers change rates.
Free calculators, always — the calculators themselves carry no paywall. We also offer an optional paid API for teams who want to automate these calculations programmatically; see Pricing for details.
Simple, honest interface — real numbers and plain-language explanations, not a black box.

Our Commitment

We believe AI infrastructure costs — and personal finance numbers, for that matter — should be transparent and easy to understand, not locked behind a sales call or a confusing pricing page. NumStack is a small, independently run project focused on getting the numbers right and being upfront about where they come from and where their limits are.

About NumStack