See demo calculators here: http://frs.nccp.org/tools/mtrc/

See policy brief here: https://aspe.hhs.gov/reports/helping-people-low-incomes

Helping People with Low Incomes Navigate Benefit Cliffs: Lessons Learned Deploying a Marginal Tax Rate Calculator

• This project developed a calculator to help people anticipate how a change in earnings from employment would affect their net income, and in so doing, provide public benefit recipients with their estimated effective marginal tax rate on new earnings.
• The calculator was designed to support program participants and caseworkers. Policy makers and program administrators may also find the calculator useful.

• Calculators were fully developed for New Hampshire, Maine, Allegheny County in Pennsylvania, and Washington, D.C., and completely customized for their local programs and rules. (To produce accurate results for users, calculators must be localized.)
• The resulting calculators captured most major federal and local means-tested benefit programs.