Why must each minimum exceed first-month interest?

That check prevents the model from silently accepting an entered minimum that cannot reduce its own debt before extra allocation.

Are minimums recalculated as balances fall?

No. Entered minimums stay fixed as assumptions until a debt is paid.

What happens to a paid debt's minimum?

Because the total monthly budget remains fixed, that amount rolls into the snowball for later debts.

Are promotional rates, fees or compounding changes modeled?

No. Each annual rate is constant; late fees, annual fees, penalties, new charges and promotional expirations are excluded.

Can I include a mortgage or student loan?

The arithmetic accepts fixed-rate debts, but the strategy may not reflect special servicing, collateral, tax or federal-program considerations.

Debt Snowball Month-by-Month Calculator

Prioritize the smallest starting balance while preserving one explicit monthly budget.

Multiple-debt collection

Payoff order

Monthly principal and interest

CurrencyExtra monthly debt budget

Debt 1

NameBalanceFixed annual rate (%)Minimum monthly payment

Debt 2

NameBalanceFixed annual rate (%)Minimum monthly payment

The model keeps the sum of entered minimums plus the extra amount as a fixed monthly budget. Each minimum must exceed that debt's first-month interest.

How to Build a Debt Snowball Estimate

Enter each debt separately so the ordering and payment-coverage checks are visible.

Select a display currency and enter the extra amount available every month.

The budget stays fixed

The model keeps the sum of starting minimums plus your extra amount available each month. When one debt is paid, its former minimum becomes part of the amount directed to the next debt.

A Balance-Ordered Simulation, Not an Optimization Claim

The engine sorts debts by starting balance, with entry order breaking equal-balance ties. Each month it adds cents-rounded interest, pays every active debt's minimum, then directs the remaining fixed budget to the first unpaid debt in that order. Amounts left after a payoff roll to the next target in the same month. A debt is rejected when its entered minimum does not exceed first-month interest, preventing a hidden negative-amortization assumption. The simulation does not compare avalanche or other strategies and does not claim to minimize interest.

Debt Snowball Examples

Two-debt snowball

Debt collection and fixed budget

debts:Card B: $500 at 0%, $25 minimum; Card A: $1,000 at 12%, $50 minimum

extraMonthlyPayment:100

Payoff simulation

Card B first, then Card A; about 9 months

The fixed monthly budget is $175. The smaller starting balance receives the extra amount.

Zero-rate boundary

Debt collection and fixed budget

debts:Small: $100, $10 minimum; Large: $200, $20 minimum

extraMonthlyPayment:20

Payoff simulation

6 months and $0 interest

The $50 fixed budget repays exactly $300 of principal.

Compare strategy and feasibility separately

A balance-first sequence may support motivation, but a different order can produce different interest. This version does not optimize or recommend an order.

Frequently Asked Questions

No. It prioritizes starting balances. A highest-rate-first strategy may produce lower interest in some scenarios, but this tool does not compare strategies.

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Debt Snowball Simulation Rules

The result comes from explicit monthly cash-flow rules rather than a closed-form payoff promise.

Formula

ascending starting balance; entry order breaks ties

Priority

ascending starting balance; entry order breaks ties

Monthly interest

rounded opening balance × annual rate / 12

Fixed budget

sum of entered starting minimums + entered extra amount

Monthly allocation

active minimums first, then remaining budget to first unpaid priority debt

Scientific Background

CFPB budgeting and debt resources emphasize understanding balances, rates, payments and creditor information. The Federal Reserve's consumer-credit materials distinguish revolving and installment debt. The snowball ordering is a user-selected behavioral strategy, not a mathematical guarantee of lowest interest.