This calculator is and will stay free, with no ads and no sign-up. If it was useful and you feel like saying thanks, you can leave a donation of any amount.
Donating is voluntary and spontaneous: it unlocks nothing, changes nothing in the tool, and nobody will know whether you donated. Using it for free is exactly what is expected.
Keeping the server and domain running, reviewing the figures for all 20 countries every year with their sources, and adding new countries and features.
Continuing opens Fourthwall's payment page, the platform HR Creativos uses, with your donation already filled in. There you pay by card, Google Pay or PayPal. Fourthwall charges no fee on donations; only the payment processor's fee applies.
This page collects no data either: the button just takes you to Fourthwall, which processes the payment under its own privacy policy.
And if you do not donate, thank you too: sharing the tool with someone who needs it helps just as much.