About Mod Math

Mod Math is a free spending calculator for car enthusiasts whose “mostly stock” build has a surprisingly long parts list. Add your modifications, see where the money went, and make a receipt you can share.

Build calculations and receipt generation happen in your browser. No account, payment, or email is required. You choose which details to include in the exported image, and saving a draft on your device is optional.

The build personalities and budget jokes are entertainment only. Money invested in a car is not a prediction of its resale value.

The optional Build Budget Toolkit is planned at $9 USD. Its proposed contents include a budget spreadsheet, priority worksheet, maintenance and installation log, parts comparison worksheet, and printable car-show build sheet. Purchasing stays disabled until the completed product and a real checkout are available.