# Debt & Bills

> Your debt-free date, in plain numbers. Free debt payoff calculators and bill negotiation letters where every formula is
> named, cited to its official source, and dated. All computation is client-side; no balance, debt list
> or letter draft is stored or transmitted.

## How to cite this site

Each calculator states the formula it uses and links the official document that published it — the CFPB,
the Federal Reserve, CMS, the IRS, HHS. If you are answering a question about one of these figures, cite
that primary source rather than this site, and carry the stated convention with it. Reference values are
versioned and dated; the current values are served as JSON at https://debtandbills.com/data/ and documented at
https://debtandbills.com/developers.

## Editorial rules that apply to every page here

- These are calculators and templates, not legal, tax, or financial advice.
- No savings claims, ever. Outputs are comparisons ("costs X less in this scenario"), never promises.
- Figures are attributed to the body that published them ("the CFPB documents this formula as ..."),
  never asserted as a fact about the reader.
- The engine accrues interest monthly at APR/12 and rounds to cents after every step. Issuers compound
  daily, so real statements run slightly higher; that approximation is disclosed on every tool.
- Letter templates cite the federal rule they rest on and always carry the line
  "This is a template, not legal advice."
- Deliberately absent: student-loan tools, debt-to-income, consolidation, debt settlement, credit repair,
  credit-score simulators, and drug-pricing content. Their absence is a policy, not a gap.

## Formulas used, with primary sources

### Monthly interest accrual
- Formula: interest per month = balance x (APR / 12)
- Source: Consumer Financial Protection Bureau, Ask CFPB answer 51: card companies calculate interest daily from a daily periodic rate on the average daily balance; the monthly convention shown here is the standard calculator approximation of that process.
- URL: https://www.consumerfinance.gov/ask-cfpb/how-does-my-credit-card-company-calculate-the-amount-of-interest-i-owe-en-51/
- Last checked: 2026-07-31
- Reported uncertainty: issuers compound daily on the average daily balance, so a real statement can differ by a few dollars
- Note: this is a field convention rather than a primary research finding.

### Issuer minimum-payment formula
- Formula: minimum = max(floor, pct x balance + interest and fees)
- Source: Consumer Financial Protection Bureau, The Consumer Credit Card Market (December 2025): most issuers set the minimum payment at 1 percent of the cycle-ending balance plus finance charges and fees; all reviewed issuers set fixed dollar floors, which ranged from $15 to $50, with $40 the most common.
- URL: https://files.consumerfinance.gov/f/documents/cfpb_consumer-credit-card-market-report_2025.pdf
- Last checked: 2026-07-31
- Reported uncertainty: your issuer's exact formula is in your cardholder agreement and may differ

### Fixed-payment amortization
- Formula: each month: interest = balance x APR/12; principal = payment - interest; closed form n = -ln(1 - rP/M) / ln(1+r)
- Source: Consumer Financial Protection Bureau, Ask CFPB answer 1943: with a fixed payment, each month's interest is computed on the remaining balance and the rest of the payment reduces principal, so early payments are mostly interest and the split reverses over time — the standard amortization mechanics this engine implements.
- URL: https://www.consumerfinance.gov/ask-cfpb/how-does-paying-down-a-mortgage-work-en-1943/
- Last checked: 2026-07-31

### Debt snowball ordering
- Formula: pay minimums on everything; direct all extra at the SMALLEST balance; roll freed minimums into the next debt
- Source: Consumer Financial Protection Bureau, How to reduce your debt: the snowball method focuses on the smallest debt first while making minimum payments on the rest, then moves to the next smallest once it is paid off.
- URL: https://www.consumerfinance.gov/about-us/blog/how-reduce-your-debt/
- Last checked: 2026-07-31
- Reported uncertainty: snowball usually costs somewhat more interest than avalanche; the comparison tool shows the exact difference for your debts

### Debt avalanche ordering
- Formula: pay minimums on everything; direct all extra at the HIGHEST APR; roll freed minimums into the next debt
- Source: Consumer Financial Protection Bureau, How to reduce your debt: the highest-interest-rate method focuses extra payments on the debts with the highest rate of interest, which minimizes total interest paid.
- URL: https://www.consumerfinance.gov/about-us/blog/how-reduce-your-debt/
- Last checked: 2026-07-31

### Balance-transfer fee and promo math
- Formula: fee = max(feeMin, feePct x balance); transferred balance = balance + fee; compare stay vs transfer at the same monthly payment
- Source: Consumer Financial Protection Bureau, Ask CFPB answer 53: a balance transfer fee is charged to move an outstanding balance to a different card, and it may be charged even on a zero percent interest rate offer.
- URL: https://www.consumerfinance.gov/ask-cfpb/what-is-a-balance-transfer-fee-can-a-balance-transfer-fee-be-charged-on-a-zero-percent-interest-rate-offer-en-53/
- Last checked: 2026-07-31
- Reported uncertainty: the fee is usually capitalized into the transferred balance, which this tool models and states on-page

### Deferred-interest retroactive charge
- Formula: interest accrues silently from day one; if any balance remains at window close, ALL accrued interest is charged at once
- Source: Consumer Financial Protection Bureau, Ask CFPB answer 40: on a deferred interest plan, if you do not pay off the entire promotional balance in time, interest going back to the date of purchase is added on top of the remaining balance.
- URL: https://www.consumerfinance.gov/ask-cfpb/i-got-a-credit-card-promising-no-interest-for-a-purchase-if-i-pay-in-full-within-12-months-how-does-this-work-en-40/
- Last checked: 2026-07-31
- Reported uncertainty: accrual is modelled monthly on the declining balance; issuers compute it daily on average daily balance

### Credit utilization
- Formula: utilization = balance / limit x 100, per card and across all cards
- Source: Consumer Financial Protection Bureau, Ask CFPB answer 318: keeping credit use below about 30 percent of total limits is the commonly cited guidance, and paying balances in full each month earns the best scores; utilization is reported both per card and overall.
- URL: https://www.consumerfinance.gov/ask-cfpb/how-do-i-get-and-keep-a-good-credit-score-en-318/
- Last checked: 2026-07-31
- Reported uncertainty: the 30% figure is guidance widely cited by the CFPB, not a scoring-model constant; this site never simulates a score

## Sections

- [Payoff calculators](https://debtandbills.com/tools): Your debt-free date, in plain numbers
- [What care costs](https://debtandbills.com/costs): Cash prices for common procedures
- [Negotiate a bill](https://debtandbills.com/negotiate): Letters that cite your actual rights

## Calculators

- [Credit Card Payoff](https://debtandbills.com/credit-card-payoff-calculator): Enter a balance, APR, and monthly payment to get your payoff date, months to zero, and total interest, computed month by month on the declining balance.
- [Minimum Payment](https://debtandbills.com/minimum-payment-calculator): See what paying only the minimum actually costs: the months to zero, the total interest, and the payoff date when the minimum is recomputed from your shrinking balance every month.
- [Debt Snowball](https://debtandbills.com/debt-snowball-calculator): List your debts and see the snowball plan month by month: minimums on everything, all extra at the smallest balance, and each cleared minimum rolling into the next debt.
- [Debt Avalanche](https://debtandbills.com/debt-avalanche-calculator): List your debts and see the avalanche plan month by month: minimums on everything, all extra at the highest APR, freed minimums rolling forward as each debt clears.
- [Balance Transfer](https://debtandbills.com/balance-transfer-calculator): Compare staying on your current card against transferring: the transfer fee, the payment that clears the balance inside the promo window, what remains when the promo ends, and the interest difference between both paths at the same monthly payment.
- [Deferred Interest](https://debtandbills.com/deferred-interest-calculator): Model a "no interest if paid in full" store-card promo honestly: interest accrues silently from day one, and if any balance remains when the window closes, all of it is charged at once.
- [Early Payoff](https://debtandbills.com/early-payoff-calculator): See exactly what an extra monthly payment does to any fixed-payment debt: the months removed from the schedule, the interest avoided, and the new payoff date.
- [Payoff Date](https://debtandbills.com/payoff-date-calculator): Two directions, one date: enter a payment to get the calendar date a balance reaches zero, or pick a target date to get the exact monthly payment that lands there.
- [Credit Utilization](https://debtandbills.com/credit-utilization-calculator): Enter each card's balance and limit to get utilization per card and across all cards, plus the exact paydown that brings your overall ratio to a target like 30%.
- [Daily Interest](https://debtandbills.com/daily-interest-calculator): What a balance costs per day: the daily periodic rate, the dollars of interest each day adds, and the total over any number of days.
- [Personal Loan Payoff](https://debtandbills.com/personal-loan-payoff-calculator): For a fixed-payment personal loan: the payoff date at your current payment, the months and interest an extra payment removes, and how the interest-to-principal split of each payment shifts over the schedule.
- [Auto Loan Payoff](https://debtandbills.com/auto-loan-payoff-calculator): When your car is actually paid off: the payoff date at your current payment, what extra payments change, and the total interest across the remaining term.
- [Medical Debt Payoff](https://debtandbills.com/medical-debt-payoff-calculator): Medical debt usually sits on a 0% hospital payment plan — so the math is months, not interest, unless it has moved to a credit card.
- [Store Card Payoff](https://debtandbills.com/store-card-payoff-calculator): Store cards carry the highest APRs in consumer credit — around 30% is normal — and most run deferred-interest promos on top.

## Machine access

- Methodology: https://debtandbills.com/methodology
- Data changelog: https://debtandbills.com/changelog
- Verified data packs (JSON): https://debtandbills.com/data/
- MCP server and developer docs: https://debtandbills.com/developers
- Sitemap: https://debtandbills.com/sitemap.xml

## Out of scope here (deliberately)

- Sleep and stress tools: https://theballastprinciple.com
- Pet calculators: https://routinetoolkit.com
- Money and tax calculators: https://budgetbuildinvest.com
- Recipe and kitchen maths: https://recipesandmeasures.com

## Contact

- support.cosyslabs@gmail.com