At any given time, nearly half a million people are detained in jails across the country because they cannot afford to post bail. In April 2018, the Vera Institute of Justice (Vera) developed the Bail Assessment Pilot, a mini demonstration project to challenge the use of bail without regard for a person’s ability to pay. A person’s ability to pay bail reflects their capacity to do so without having to forgo paying their rent, groceries, child care, or other regular expenses. The Bail Assessment Pilot required the use of the “ability to pay calculator,” made available by this application. Vera’s ability to pay calculator can offer two pieces of vital information to the courts: one is the form of bail the person has access to and the second is the amount of bail the person can reasonably pay. These factors reflect an individual’s financial circumstances based on information about their income, benefits, assets, and expenses. Using this app, a judge’s bail decision can be informed by a specific amount and form of bail that would not cause “undue hardship,” and can potentially prevent the use of unnecessary pretrial detention.