Installment True APR Calculator
See the real interest rate hiding behind "0%" installment and BNPL plans.
Debt & credit
A lower monthly payment and a lower cost are different things. These pages recover the annualised cost hidden inside instalment plans, card fees, and refinancing offers, and show the debt-to-income ratio lenders actually read.
Calculators for this decision
Cashback Break-even Calculator
Check whether an annual-fee card beats a no-fee 1% card at your spending level.
Credit Card Payoff & Interest Calculator
Estimate payoff time and total interest for a fixed payment or a target payoff date, including promotional APR expiry and new monthly charges.
Debt Snowball vs Avalanche Calculator
Compare payoff order, total interest, and debt-free date for snowball, avalanche, and custom strategies across multiple debts.
Debt-to-Income (DTI) Ratio Calculator
Calculate front-end and back-end debt-to-income ratios, compare against FHA/VA/conventional benchmarks, and test how paying off one debt changes the result.
Guides that explain the decision
- APR vs. APY: Why Borrowing Rates and Savings Yields Are Not the Same Number
- Buy now, pay later vs credit-card installments: compare total cost and timing
- Cashback caps and bonus categories: calculate your real reward rate
- Credit Card Annual Fee Break-Even: How Much to Spend on a $95 Fee
- Debt Snowball vs. Avalanche: What the Math (and the Research) Actually Show
- How to Calculate DTI (And Why 43% Isn't a Hard Cutoff Anymore)
- How to Calculate the Real APR of a 0% Installment Plan
- How upfront fees change the true cost of financing
- Installment Fee to APR Conversion Table: A 3% Fee Is Not a 3% Rate
- Loan Term vs. Monthly Payment: Why a Lower Payment Can Cost More Overall
- Why Your Credit Card Statement Warns You About the Minimum Payment
- After Debt Payoff: Stop Lifestyle Creep From Replacing the Payment You Just Eliminated
How to read these pages
Each calculator applies a stated formula to the numbers you enter and shows the threshold where the answer flips. The default values are editable examples, not market averages or quotes. Nothing here is financial advice: confirm current prices, rates, fees, taxes and contract terms before acting on a result.