What this planner works out
Enter your debts one per line — name, balance and minimum payment — and this planner sorts them smallest balance first and tells you where to direct your extra payment. That order is the debt snowball method.
The tool orders the debts and identifies the target; it does not project a payoff date, because that depends on interest rates it does not ask for. Use it to decide the sequence, then use the Credit Card Repayment Calculator for the timing on each individual balance.
Enter your details
Before you build the list
- List every debt, including catalogue accounts, buy-now-pay-later balances, overdrafts and money owed to family. Debts left off the list do not stop existing.
- Use current balances from statements or your online account rather than remembered figures.
- Record the true contractual minimum for each debt. Missing a minimum payment risks fees and damage to your credit file, which the snowball method depends on avoiding.
- Work out the extra amount from your budget, not from optimism. A snowball only works if it survives an ordinary month.
When the smallest debt clears, its minimum payment is not absorbed back into spending. It is added to the extra payment and directed at the next debt, so the amount attacking each successive balance grows. Momentum builds even though your total monthly outlay stays the same.
How this calculator works
The planner sorts your debts by balance, smallest first, and applies a single rule:
Pay the contractual minimum on every debt
Direct all spare money at the smallest balance
When it clears, add its minimum to the spare money and move to the nextOrdering by balance rather than by interest rate is a deliberate behavioural choice. It is not the cheapest route — that is the avalanche method — but clearing a whole debt early produces visible progress, and evidence from behavioural research suggests people are more likely to persist with a plan that produces early wins.
The tool does not model interest, so the order it gives is based purely on balance size.
Worked example: three debts and £100 spare
Using the default list — a catalogue account of £350 with a £25 minimum, a credit card of £1,200 with a £50 minimum, and a loan of £2,400 with a £120 minimum, plus £100 spare each month:
- Order: catalogue (£350), then credit card (£1,200), then loan (£2,400)
- Month one: pay £50 and £120 as minimums, and £125 at the catalogue account (£25 minimum plus £100 spare)
- The catalogue clears in about three months. Its £25 minimum now joins the snowball
- The card now receives £175 a month — £50 minimum plus £125 rolled forward
- When the card clears, the loan receives £295 a month while your total outlay never changed
Total monthly spending on debt stays at £295 throughout. All that changes is where it is aimed, and the effect compounds as each debt falls away.
Common mistakes
- Reducing total payments when a debt clears. The freed-up money must roll forward, or the method does nothing at all.
- Leaving debts off the list. Overdrafts and buy-now-pay-later balances are frequently forgotten and are often expensive.
- Using the snowball while a very high-rate debt sits at the bottom. If one debt charges dramatically more than the rest, consider the avalanche method instead.
- Missing a minimum payment to overpay elsewhere. This causes fees and credit file damage that outweigh the gain.
- Starting with no buffer. Without a small emergency fund, the next unexpected cost goes on credit and the snowball goes backwards.
Frequently asked questions
Snowball or avalanche — which should I use?
The avalanche method, which targets the highest interest rate first, always costs less in pure arithmetic. The snowball clears whole debts sooner and is easier to stick to. If the rates on your debts are broadly similar, the difference in cost is small and the snowball's motivational advantage usually wins. If one debt is charging far more than the others, the avalanche is worth the patience. The comparison tool linked below walks through this.
Should I include my mortgage?
Generally not. Mortgages are secured, long-term and usually charged at much lower rates than consumer credit, so including one distorts the ordering. Deal with unsecured debts first, then consider overpaying the mortgage separately.
What about a 0% credit card?
Keep making at least the minimum, and note when the promotional period ends. It is often sensible to clear interest-bearing debts first, but you must have a plan for the 0% balance before the rate reverts, or it will jump to the top of the list overnight.
Does this affect my credit score?
Reducing balances and maintaining every minimum payment generally helps over time, because both payment history and how much of your available credit you are using are significant factors. Closing accounts as they clear can occasionally have the opposite effect by reducing your available credit, so there is no need to rush to close them.
What if the minimums alone are unaffordable?
That is a signal to get free advice rather than to optimise an ordering. Citizens Advice, StepChange and National Debtline all offer free, confidential help and can discuss options that a repayment plan cannot reach on its own.
Related tools
References
- MoneyHelper — free UK debt guidance and routes to regulated debt advice charities
- Financial Conduct Authority — rules requiring lenders to support customers in financial difficulty
Sources are checked at publication and can change — how I choose and check references.