Every tool here does one job a bowler actually asks about, and each one explains the rule or the arithmetic it uses rather than hiding it. The spare calculator tells you where to stand and aim for any leave using the USBC 3-6-9 system or the plastic-ball system; the score calculator and the handicap calculator apply USBC Rule 2 and USBC’s own handicap research; the ball weight selector starts from the equipment manual’s 16-pound limit; and the ball speed and rev rate tool measures your shot from a slow-motion phone video. The breakpoint calculator turns an oil pattern length into a starting board with USBC’s Rule of 31. The USBC approved ball lookup searches the approved and non-conforming lists, and the arsenal builder shows what your bag covers.
For keeping score, the score tracker reads a photo of the scoring screen and keeps your average or a whole league, and the retro score sheet prints a customizable sheet for doing it by hand. Nothing here needs an account, though a free one lets the tracker follow you between devices. Not sure what you need? Ask BR answers bowling questions from the site’s own sourced pages.