Credit Card Payoff Calculator UK — Discovery Notes
JTBD
“How long will it take me to pay off my credit card?” / “How much interest am I actually paying?” / “Is a balance transfer worth it?” / “Should I use snowball or avalanche for my three credit cards?”
Target Audience
- UK adults carrying a revolving credit card balance (FCA data: ~10 million UK cardholders in persistent debt at any time)
- People who have just received an FCA persistent debt letter and need to understand their options
- Individuals considering a 0% balance transfer offer and wanting to quantify the saving
- Households managing multiple credit cards, seeking a structured payoff strategy
- Debt advisers and MoneyHelper users needing a shareable calculation
Calculator Tabs (3)
Tab 1: Payoff Calculator
- Inputs: Current balance (£), APR (%), monthly payment (£)
- Outputs: Months to pay off, total interest, total paid, minimum payment comparison (months + interest at minimum), interest saved vs minimum, time saved vs minimum
- Key insight: Showing minimum payment cost vs a modest fixed payment is the primary sharing trigger
- Warnings: FCA 18-month persistent debt threshold; FCA 36-month threshold; payment below minimum
Tab 2: Balance Transfer
- Inputs: Current balance (£), current APR (%), 0% period (months), BT fee (%), monthly payment (£)
- Outputs: Transfer fee (£), monthly payment needed to clear in 0% period, time and interest on current card, BT cost breakdown, total saving
- Key insight: “You need £X/month to clear it in time” is actionable and shareable
- Warnings: If payment is insufficient to clear in 0% period; if saving is negative
Tab 3: Multiple Cards
- Inputs: Up to 5 cards (balance, APR, min payment), extra monthly payment, strategy selector (avalanche/snowball)
- Outputs: Per-strategy: months to debt-free, total interest, total paid; comparison row showing saving and time difference
- Key insight: Avalanche vs snowball comparison answers a common search query directly
Regulatory Context
FCA Persistent Debt Rules (CONC 6.7 / PS18/4)
- Persistent debt definition: More paid in interest and charges than principal over 18 consecutive months
- 18-month action: Lender must contact customer, explain persistent debt, encourage faster repayment
- 27-month check: Lender assesses trajectory, considers further intervention
- 36-month action: Lender must offer structured repayment plan (3-4 years); must consider suspending/reducing interest if customer cannot afford plan
- Source: FCA PS18/4 (February 2018), effective March 2018 (implementation September 2018)
UK Minimum Payment Standard
- Most UK lenders: Max(£25, 1% of balance + monthly interest charge)
- Some lenders: 2-2.5% of balance as flat formula
- Regulatory context: No FCA-mandated minimum formula, but FCA expects lenders not to set minimums so low they trap customers in long-term debt (FCA Credit Card Market Study, 2016)
UK Credit Card APR Data (verified March 2026)
- Bank of England MBOS: average purchase rate ~26.8% as of January 2026
- Average APR (including fees): ~36% per NimbleFins/Moneyfacts data (January 2026)
- Standard purchase rate on mainstream cards: typically 20-27% APR
- Default in calculator: 23% (representative for standard purchase credit cards)
- Store card rates: typically 30-40% APR
Balance Transfer Market (UK, early 2026)
- 0% periods available: 12-30 months (longest offers from major banks)
- Transfer fees: 1.5-3.5% on most offers; a few 0% fee cards with shorter periods
- Revert rate: typically 20-27% APR after offer ends
- Cannot transfer between cards in the same banking group
Key Data Points (verified)
| Metric | Value | Source |
|---|
| Average UK credit card purchase rate | ~26.8% (Jan 2026) | Bank of England MBOS |
| Persistent debt threshold 1 | 18 months | FCA CONC 6.7 |
| Persistent debt threshold 2 | 36 months | FCA CONC 6.7A |
| Reasonable repayment period (FCA) | 3-4 years | FCA PS18/4 |
| Typical UK minimum payment floor | £25 | Industry standard |
| Typical BT 0% period | 18-30 months | Market data March 2026 |
| Typical BT fee | 1.5-3.5% | Market data March 2026 |
Monthly interest rate = APR / 12 / 100
Months to payoff = -ln(1 - (monthly_rate × balance / payment)) / ln(1 + monthly_rate)
(requires payment > balance × monthly_rate)
Total interest = (payment × months) - balance
Minimum payment = Max(25, balance × 0.01 + balance × monthly_rate)
BT fee = balance × fee_pct / 100
Monthly to clear in period = (balance + fee) / period_months
Avalanche: extra payment → highest APR card first
Snowball: extra payment → smallest balance card first
- MoneySavingExpert credit card calculator (basic payoff + BT comparison)
- Barclays card repayment calculator (own-product only)
- MoneySuperMarket debt calculator (lead-gen focused)
- StepChange debt advice tool (debt management focus, not pure calculation)
- Nationwide, HSBC: basic repayment calculators on product pages
Differentiation sum.money:
- Only free UK tool with all three: payoff + balance transfer + multi-card strategies in one place
- FCA persistent debt warnings surfaced inline (not in collapsible notes)
- Shareable URLs for all scenarios
- No registration, no lead generation
SEO Potential
- Keyword: “credit card payoff calculator UK” — high volume, transactional
- Keyword: “how long to pay off credit card UK” — high volume, informational
- Keyword: “balance transfer calculator UK” — high volume, transactional
- Keyword: “snowball vs avalanche calculator UK” — medium volume, informational
- Keyword: “FCA persistent debt credit card” — medium, informational
- Keyword: “minimum payment credit card calculator UK” — medium, transactional
- Long-tail: “how long to pay off £5000 credit card” — very transactional
- /uk/debt-consolidation-calculator — Combine multiple debts
- /uk/personal-loan-calculator — Compare with a fixed-rate personal loan
- /uk/savings-interest-calculator — Saving vs paying off debt decision
- /uk/budget-calculator — Find money to accelerate repayment
- /uk/mortgage-overpayment-calculator — Next step after clearing cards
- /uk/savings-goal-calculator — Build emergency fund to avoid future card debt
Sources
- FCA PS18/4: Credit Cards (Persistent Debt and Earlier Intervention) Instrument 2018
- FCA CONC 6.7 and CONC 6.7A (Consumer Credit sourcebook)
- Bank of England MBOS Table A5.6: Interest rates on sterling bank and building society deposits and time deposits (January 2026)
- FCA Credit Card Market Study: Final Findings Report (July 2016)
- National Debtline persistent debt guidance (nationaldebtline.org)
- StepChange Debt Charity — UK credit card debt statistics