Methodology
How Beanios calculates estimates
We separate calculator logic from presentation, keep inputs explicit, and state what each result includes and excludes.
Mortgage monthly payment
The loan amount is the home price minus the down payment. Principal and interest use the standard fixed-rate amortization formula with monthly compounding over 180 payments for a 15-year term or 360 payments for a 30-year term.
Annual property tax and homeowners insurance are each divided by 12 and added to principal and interest. Estimated PMI is also included when the down payment is below 20%. Lifetime interest is total principal and interest payments over the term minus the original loan amount. Remaining balance follows the standard amortization balance formula.
Estimated PMI
Beanios uses an adjustable annual PMI rate of 0.6% by default and applies it to the current loan amount. The estimated duration assumes a conventional loan and that the borrower requests cancellation when the scheduled balance reaches 80% of the original home price. Actual eligibility, cost, and timing depend on the loan and servicer. Automatic termination generally occurs later, when the scheduled balance reaches 78%, if applicable requirements are met. Read the CFPB guidance.
Mortgage comparisons
Interest-rate comparisons change only the rate. The same-payment home price is solved by finding the price that returns the selected monthly total while preserving the down-payment percentage and annual tax and insurance inputs.
Home-price comparisons preserve the selected down-payment percentage, interest rate, term, annual property tax, annual homeowners insurance, and PMI rate. Down-payment comparisons change the amount paid upfront while holding the other entered assumptions fixed. Loan-term comparisons use the same loan and selected interest rate for both terms. Payoff dates assume payments begin now, and extra-payment estimates compare principal and interest only.
Auto loan payment and down payment
The amount financed equals the vehicle price plus estimated sales tax, fees, and negative trade equity, minus the down payment and positive trade equity. Trade equity is the trade-in value minus the amount still owed on the trade-in.
Sales tax is estimated by multiplying the full vehicle price by the entered sales-tax rate. This version does not reduce the taxable vehicle price for a trade-in because state and local rules vary.
The estimated monthly payment uses the standard fixed-rate amortization formula over 36, 48, 60, 72, or 84 monthly payments. At 0% APR, the amount financed is divided evenly across the term. Lifetime interest equals total scheduled loan payments minus the original amount financed. Down-payment comparisons hold APR and the other purchase assumptions constant so they isolate the effect of changing cash down.
Car affordability
Beanios subtracts monthly insurance, energy, and maintenance estimates from the selected total monthly budget. It converts the remaining payment capacity into an affordable amount financed using the entered APR and term, then solves for a vehicle price after the down payment, trade equity, sales tax, and fees.
Fuel and charging cost
Annual commute miles equal the one-way commute multiplied by two, commute days per week, and commute weeks per year. Other weekly driving is multiplied by 52 and added to commute miles.
Gas use equals annual miles divided by MPG. Electric use converts MPGe with 33.7 kilowatt-hours per gallon equivalent, so annual kilowatt-hours equal annual miles multiplied by 33.7 and divided by MPGe. Energy use is multiplied by the entered local price.
Auto refinance
The current-loan estimate amortizes the entered balance over the remaining months at the current APR. The refinance estimate amortizes the current balance plus entered refinance fees over the new term at the new APR.
Net remaining savings compares all scheduled payments from today forward. Break-even divides refinance fees by the estimated monthly payment reduction. A lower payment can still produce a higher remaining cost when the new term is longer.
Debt payoff strategies
Each month, interest is added to every active debt using APR divided by 12. The calculator pays every entered minimum, then directs the remaining monthly debt budget to a target debt. Freed-up minimum payments remain in the fixed monthly budget after a debt is paid off.
The avalanche targets the highest APR first. The snowball targets the smallest balance first. The extra-payment comparison uses the avalanche in both schedules and compares the entered minimums alone with minimums plus the selected extra payment.
Credit card payoff
The fixed-payment schedule applies the same entered payment each month. The estimated minimum-payment schedule uses the larger of the entered dollar floor or the entered percentage of principal plus that month's interest. Actual issuer formulas can include fees and other rules, so the minimum-payment schedule is an estimate.
Balance transfer
The transfer fee is the entered percentage of the moved balance and is added to the transferred balance. The promotional APR applies for the selected number of months. Any remaining balance then uses the entered post-promotion APR.
The break-even month is the first promotional month when interest avoided on the current card is at least as large as the transfer fee plus promotional interest. Full-payoff comparisons apply the same monthly payment to both options.
Retirement savings
When contribution percentages are used, the personal monthly contribution equals annual salary multiplied by the personal contribution rate, divided by 12. The employer monthly contribution uses the smaller of the personal contribution rate or match limit, multiplied by salary and the employer match rate, then divided by 12. Direct monthly amounts can be entered instead.
The projection converts the entered annual return into an equivalent monthly rate. Each month, the model applies investment growth to the existing balance, then adds the personal and employer contributions. This repeats through the selected retirement age.
Investment growth equals the projected ending balance minus current savings and all future contributions. The today's-dollar result divides the future balance by the entered annual inflation assumption over the years remaining to retirement. Tradeoff comparisons change only the displayed contribution, retirement age, or return assumption while keeping the other entered values fixed.
401(k) contribution and employer match
The annual personal contribution equals salary multiplied by the personal contribution rate. The employer contribution uses the smaller of the personal contribution rate or the match limit, multiplied by salary and the employer match rate. The missed match is the difference between the maximum employer contribution allowed by that formula and the estimated employer contribution received.
The retirement projection converts the annual return assumption into an equivalent monthly rate, applies growth monthly, and adds personal and employer contributions separately. Salary, contribution rates, and the employer formula remain constant. The model does not enforce plan or legal contribution limits.
Rounding and limits
Displayed amounts are rounded for readability. Internal calculations retain full numeric precision. Estimates assume constant rates and scheduled monthly payments unless a calculator explicitly states otherwise.
Updated August 26, 2026.