Understand your money one decision at a time
Build a personal financial model instead of guessing.
Use 18 private calculators for everyday financial decisions, then follow them from monthly cash flow to a retirement model.
Formula, assumptions and interpretation
Personal finance calculators
18 calculators
Budgeting and financial resilience
5 toolsMonthly budget
Compare monthly take-home income with spending and calculate the amount left to save or repay debt.
Open calculator Runs locallySavings rate
Measure the share of take-home income retained as savings during a month.
Open calculator Runs locally50/30/20 budget
Split monthly take-home income into illustrative needs, wants and savings or debt-payment amounts.
Open calculator Runs locallyEmergency fund target
Estimate an emergency reserve from essential monthly expenses and a selected number of months.
Open calculator Runs locallyEmergency fund coverage
Calculate how many months current emergency savings could cover essential spending.
Open calculatorDebt and repayment
3 toolsDebt-to-income ratio
Compare required monthly debt payments with gross monthly income.
Open calculator Runs locallyLoan payoff time
Estimate the time and total interest required to repay a fixed-rate balance with fixed monthly payments.
Open calculator Runs locallyExtra debt payment
Compare a normal repayment schedule with the same debt after adding a fixed extra monthly payment.
Open calculatorSaving and investing
4 toolsCompound savings growth
Project how a lump-sum saving could grow through annual compound returns.
Open calculator Runs locallyMonthly savings growth
Project an initial balance plus equal end-of-month contributions at a constant annual return.
Open calculator Runs locallyInvestment fee impact
Compare projected compound growth before and after an annual percentage fee.
Open calculator Runs locallyInvestment CAGR
Calculate the constant annual growth rate connecting a starting investment to an ending value.
Open calculatorHousing and retirement
6 toolsMortgage payment
Estimate monthly principal and interest for a fixed-rate repayment mortgage.
Open calculator Runs locallyHome down payment
Convert a home price and down-payment percentage into cash required and mortgage principal.
Open calculator Runs locallyHome affordability by payment
Estimate a mortgage principal from gross income, a selected housing ratio, rate and term.
Open calculator Runs locallyRetirement savings target
Estimate a portfolio target from annual retirement spending and a selected withdrawal rate.
Open calculator Runs locallyRequired retirement contribution
Estimate the equal monthly contribution required to reach a target after allowing current savings to grow.
Open calculator Runs locallyRetirement withdrawal income
Translate a portfolio balance and selected annual withdrawal rate into annual and monthly income.
Open calculatorClear answers
About the personal finance tools
Where should a personal-finance beginner start?
Start with monthly cash flow, then build an emergency reserve before studying debt, compound growth, housing and retirement. The Personal Finance from Zero path puts all 18 lessons in that order.
Are my financial figures uploaded?
No. Calculations run locally in your browser. Values are not transmitted or stored unless you explicitly choose an account feature that saves work.
Is this financial or investment advice?
No. These are transparent educational models. Returns, inflation, fees, tax, law and personal circumstances can change real outcomes, so verify important decisions with qualified guidance.