> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt
> Use this file to discover all available pages before exploring further.

# Fee Calculator

> Use the Fee Calculator in the Console to estimate and validate how Fee Packages apply before processing Transactions.

The **Fee Calculator** previews how fees will be applied before you run a real Transaction. It uses an existing [Fee Package](/en/lerian-console/midaz-console/managing-fee-packages) to estimate the total charged and shows a detailed breakdown of each rule — flat fees, percentages, deductibles, and more.

Use it when testing changes, validating logic with business teams, or building fee previews in your product UI.

## Accessing the Fee Calculator

***

<Steps>
  <Step>
    In the Midaz Module sidebar, expand **Fees Engine**.
  </Step>

  <Step>
    Click **Calculator** to open the Fee Calculator page.
  </Step>
</Steps>

<Warning>
  You need at least one [Fee Package](/en/lerian-console/midaz-console/fe-creating-a-package) before using the Calculator — the estimator must run against a saved package.
</Warning>

## Why use the Fee Calculator

***

The Fee Calculator is a read-only tool that does not affect the ledger or create any transactions. Use it to:

* **Validate new fee packages** before enabling them in production
* **Test edge cases** at minimum and maximum amount boundaries
* **Compare fee structures** by running the same transaction through different packages
* **Document expected fees** for finance teams or customers
* **Debug fee issues** by reproducing scenarios and analyzing calculation breakdowns