OddsConvertRuler

Odds are written in three different ways, and the switch between
them is where most of the mistakes happen. OddsConvertRuler keeps
that arithmetic in one place, so a price can be read, compared and
understood without opening a second screen.

The app opens on a board that shows the market you were last
working on: what each selection pays, how much of the book it
carries, and how much of that book is margin. Open any sheet and
the same numbers appear as a ledger, one line per outcome, so the
gap between what a book charges and what the prices imply is easy
to see.

A conversion desk takes a decimal price and returns the fraction
and the American line, together with the chance it implies. When a
whole market is entered, the app lifts the margin out of every
selection and re-normalizes them, which is the fair way to compare
two books quoting the same game. A parlay desk multiplies the legs
so the joint chance is visible instead of guessed at, and a Kelly
desk turns your own estimate into a bankroll fraction, with half
and quarter versions for people who prefer a quieter ride.

Everything you enter stays on the phone. There is no account, no
sync and no analytics. It is a small tool for people who like the
numbers to add up.