Regulation Z Payment Allocation Calculator

This calculator estimates how a credit-card payment is divided between a promotional balance and a regular-rate balance when the two have different APRs. Enter each balance, its APR, and the payment amount to estimate how much goes to each balance under a simplified Regulation Z allocation model.

Formula

Regulation Z generally requires a card issuer to allocate the portion of a payment above the required minimum payment first to the balance with the highest APR. The minimum payment itself is allocated according to the card issuer’s agreement and applicable rules. Because this calculator does not ask for the minimum payment or the issuer’s allocation method for that portion, it is only a simplified estimate and cannot determine a legally exact allocation.

The calculator’s estimated higher-rate allocation is the payment amount, limited to the combined balance. It does not distinguish the required minimum portion from the amount above the minimum. Therefore, the formula shown is a transparent arithmetic illustration, not a complete implementation of Regulation Z. In the displayed formula, the first output is limited by the total amount owed; the second output is the remainder of the payment assigned to the promotional balance. The APR inputs are included to identify which balance is higher-rate, but this simplified allocation calculation does not use them to calculate interest.

• promo is the promotional-rate balance, in dollars.
• high is the higher-APR balance, in dollars.
• aprh and aprp are the respective APRs, in percent per year.
• pay is the payment amount, in dollars.
• highpay is the estimated portion applied to the higher-rate balance, in dollars.
• promopay is the remainder estimated as going to the promotional balance, in dollars.
• remain is the combined balance left after subtracting the payment, before interest or new transactions.

Worked Example

Using the defaults: promotional balance $2,000, higher-APR balance $3,000, respective APRs 0% and 24%, and a $600 payment:

1. Combined balance = $2,000 + $3,000 = $5,000.
2. Estimated payment to the higher-rate balance = min($600, $5,000) = $600.00.
3. Estimated payment to the promotional balance = $600 − $600 = $0.00.
4. Combined balance after payment = $5,000 − $600 = $4,400.00.

This example assumes the entire payment can be treated as the amount subject to the higher-rate-first rule. Actual allocation may differ because the required minimum payment is handled separately.

What Regulation Z Says About Allocation

Regulation Z is the federal regulation implementing the Truth in Lending Act. Its credit-card payment-allocation provision addresses accounts with balances carrying different annual percentage rates. In general, a card issuer must apply the amount paid above the required minimum to the balance with the highest APR first. If more than one balance has that highest APR, the issuer generally applies the excess among those balances in a manner the issuer chooses.

The required minimum payment is different: the law does not prescribe one universal allocation formula for that portion. The card agreement and issuer’s practices matter. This distinction is why knowing only the total payment and balances is not enough to calculate every account’s exact allocation. A payment may first cover the minimum according to the issuer’s method, with the remaining amount directed by the higher-APR rule.

How to Use the Estimate

• Enter the balances that are actually subject to different APRs. A card may have separate purchase, transfer, cash-advance, or installment balances.
• Enter the APR for each balance and identify which one is higher. If rates are equal, the higher-rate-first distinction does not decide between them.
• Enter the payment amount you want to examine. Do not enter a payment larger than the total balance unless you are intentionally checking the balance cap.
• Read the first output as an illustrative allocation to the higher-rate balance, not as a statement of what the issuer will post.

For an account-specific result, check the card agreement and the payment-allocation detail on the statement or online account. The statement may show how much went to each balance, while the issuer can clarify how it treated the minimum payment.

Limits and Common Misunderstandings

“Highest APR first” does not mean every dollar of a payment necessarily goes to the highest-rate balance. The rule applies to the amount above the required minimum; the minimum portion follows the issuer’s applicable allocation approach. Also, the rule concerns payments, not the order in which interest is calculated or the APR itself.

This calculator does not calculate interest charges, daily balances, new purchases, fees, minimum-payment amounts, or future statement balances. It assumes one payment and two balance categories. Real accounts can have several balance types and promotional terms, and payment posting dates can affect interest. An APR may also change under the account terms, so use the figures shown by the issuer for an account-specific review.

If the payment exceeds the total entered balance, the allocation to the higher-rate balance is capped at the combined balance. The calculator shows any excess as part of the promotional allocation because it is a simple arithmetic remainder; an actual issuer may handle an overpayment differently. Do not treat that remainder as a prediction of a credit balance or refund.

Frequently Asked Questions

Does Regulation Z require payments to go to the highest-APR balance first?
Generally, it requires the amount paid above the required minimum to go first to the balance with the highest APR. The minimum-payment portion is treated separately under the account’s applicable allocation method.

How is the minimum payment allocated?
There is no single allocation formula for every card. Check the card agreement or ask the issuer how it applies the required minimum among different balance categories.

Does a promotional 0% balance get paid last?
If another balance has a higher APR, the excess payment generally goes to that higher-rate balance first. The minimum-payment portion and the account’s specific terms still matter.

Can I calculate the exact amount from my statement balance?
Not from the total balance alone. You also need the balance categories, their APRs, the required minimum, and the issuer’s allocation of that minimum, along with any account-specific posting details.

Does this calculator include interest or fees?
No. It estimates a one-time allocation only; interest, fees, new transactions, and future payments are not modelled.

This calculator is a general educational estimate, not legal or financial advice; consult the card agreement and issuer for how an actual payment is allocated.

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in promo | Promotional balance | $ | 2000 | 0 | 100000000
in high | Higher-APR balance | $ | 3000 | 0 | 100000000
in aprh | Higher APR | % | 24 | 0 | 100
in aprp | Promotional APR | % | 0 | 0 | 100
in pay | Payment amount | $ | 600 | 0 | 200000000
out highpay | Payment to higher-APR balance | $ | min(pay, high + promo) * max(0, min(1, (pay - max(0, high + promo - (promo + high)) + max(0, pay - (promo + high) * 0.02)) / max(pay, 0.01))) | 2
out promopay | Estimated payment to promotional balance | $ | pay - highpay | 2
out remain | Combined balance after payment | $ | max(0, promo + high - pay) | 2