Updated July 2026. What a token cost calculator does, how to use one in four steps, and how to read the result — so you know an LLM's price before you ship, not after the invoice.
A token cost calculator turns an LLM's per-million-token rate into a real number for your workload. Instead of guessing what GPT, Claude or Gemini will cost, you enter your tokens and see the bill. This guide shows how to use one properly — and the free calculator on this site does every step for you across 21 models.
It applies one formula: (input_tokens × input_rate) + (output_tokens × output_rate), with both rates per million tokens. That sounds simple, but doing it by hand for every model and every volume is where people give up — which is the whole point of a calculator.
A good calculator splits input cost from output cost so you can see which side to optimize. If output dominates, cap max_tokens or pick a model with a lower output rate. If input dominates (RAG, long context), prompt caching is your lever. The token basics behind these numbers are in AI token cost explained, and the per-provider rates are in LLM token pricing compared.
The gap between models is enormous at scale. A workload that costs $2,000/month on a flagship can cost $400 on a mid-tier model with no meaningful quality loss for the task — but you only find that out by calculating first. Estimating up front is the difference between a predictable bill and a surprise invoice. For a model-by-model plan, see the cheapest LLM API by workload.
A tool that estimates an LLM API call's cost from your input and output token counts and the model's per-million rate. The gpt-cost.com calculator does it free for 21 models.
Pick a model, enter or paste your prompt, add expected output length, and set requests per month. It returns per-call and monthly cost with input and output split out.
Yes — completely free, no signup, covering 21 production models across five providers.
Token estimates using the ~4-characters-per-token heuristic match official tokenizers within a few percent for English. For exact billing use the provider's official tokenizer; for budgeting a calculator is precise enough.
Prices synced from each vendor's official pricing page, July 2026. For exact billing, use each provider's official tokenizer.