Open Engineering
Free Financial & Planning Calculators
Fast, mathematically grounded calculators with zero sign-ups or email gates. Calculate metrics in seconds, then upgrade to full unlocked Excel & Google Sheets workbooks when you are ready.
real estate investors
Open Tool →Cap Rate & DSCR Calculator
Input your purchase price and rent roll. Get instant Cap Rate, NOI, and Debt Service Coverage.
independent operators & freelancers
Open Tool →1099 & Self-Employment Tax Calculator
Calculate your monthly tax reserve for 1099 income, freelance work, and small business profit.
savers & operators
Open Tool →Compound Interest & Wealth Calculator
See how consistent monthly contributions compound into long-term financial independence.