31 calculators. Zero friction.
The math behind the biggest money decisions — borrowing, saving, investing, retirement, taxes, real estate, insurance, and global moves. All free, all live, all yours.
Monthly payment + total interest over the life of the loan.
How long, how much interest, what to add to clear it faster.
Payment + interest for a car loan, with trade-in handling.
Does refinancing actually save you money?
Roll multiple debts into one — see if it helps.
How big should your buffer actually be?
Test your spending mix against the classic rule.
Save monthly for a known future expense.
How long until you hit a target with interest.
Invest all at once or spread it out?
What a 1% fee costs you over 30 years.
A simple stocks/bonds/cash split based on your horizon.
Value of compounding dividends vs taking them in cash.
After-tax benefit of realizing a loss this year.
Project any account forward with contributions.
Find your financial independence target.
After-tax value of pre-tax vs Roth contributions.
When can you stop saving and still retire on time?
Lifetime benefits at 62 vs 67 vs 70.
Your true tax rate using US federal brackets.
Short vs long-term tax on an investment sale.
Estimate self-employment + income tax owed.
Compare 5-year cost of renting vs owning the same home.
Quick yield check on a rental property.
Annual cash flow vs the cash you actually put in.
How much capital you pull back out of a deal.
How much coverage your family actually needs.
How much liability insurance to carry.
Tax savings on each, side by side.
What a currency swing does to your foreign holdings.
Same lifestyle, different city — what salary do you need?
Mortgage payment
Monthly payment + total interest over the life of the loan.
Credit card payoff
How long, how much interest, what to add to clear it faster.
Auto loan
Payment + interest for a car loan, with trade-in handling.
Student loan refinance
Does refinancing actually save you money?
Federal loans: refinancing forfeits IDR plans and forgiveness.
Debt consolidation
Roll multiple debts into one — see if it helps.
Emergency fund
How big should your buffer actually be?
50 / 30 / 20 budget
Test your spending mix against the classic rule.
Sinking funds
Save monthly for a known future expense.
Savings goal timer
How long until you hit a target with interest.
DCA vs lump sum
Invest all at once or spread it out?
DCA reduces regret and timing risk; on average lump sum wins because markets rise more often than they fall.
Expense ratio drag
What a 1% fee costs you over 30 years.
Asset allocation by age
A simple stocks/bonds/cash split based on your horizon.
Classic rule of thumb. Adjust for pensions, real estate, and risk tolerance.
Dividend reinvestment
Value of compounding dividends vs taking them in cash.
Tax-loss harvesting
After-tax benefit of realizing a loss this year.
Watch the 30-day wash-sale rule — buy a similar but not identical security.
Compound growth
Project any account forward with contributions.
4% rule / FI number
Find your financial independence target.
Roth vs 401(k)
After-tax value of pre-tax vs Roth contributions.
Coast FIRE
When can you stop saving and still retire on time?
Social Security timing
Lifetime benefits at 62 vs 67 vs 70.
Marginal vs effective tax
Your true tax rate using US federal brackets.
Capital gains tax
Short vs long-term tax on an investment sale.
Side-hustle tax
Estimate self-employment + income tax owed.
Rent vs buy
Compare 5-year cost of renting vs owning the same home.
Cap rate
Quick yield check on a rental property.
Cash-on-cash return
Annual cash flow vs the cash you actually put in.
BRRRR estimator
How much capital you pull back out of a deal.
Term life sizing
How much coverage your family actually needs.
Term policies (20–30 yr) usually cost a fraction of whole life with the same coverage.
Umbrella coverage
How much liability insurance to carry.
~$200–$400/yr per $1M is typical. Required: max auto & home liability first.
HSA vs FSA
Tax savings on each, side by side.
HSA wins long-term — invest the balance and reimburse yourself decades later, tax-free.
FX impact
What a currency swing does to your foreign holdings.
Cost-of-living swap
Same lifestyle, different city — what salary do you need?
Find COL indexes on Numbeo or BestPlaces (NYC ≈ 100 in many sources).