Card Grace Period Trailing Interest Checker

Accrue simple trailing interest over actual post-statement balance/day bins, rounding once over caller day basis and explicit remaining-grace evidence; no unobserved payment dates, compounding or issuer grace restoration inferred.

Description

Trailing interest follows post-statement balance exposure over measured day bins.

Trailing interest follows post-statement balance exposure over measured day bins. Explicit grace evidence can suppress interest without discarding observed days.^[1]

The returned values include Modeled trailing interest minor, Interest bearing observed days, Interest suppressed by caller grace evidence. The How section below explains the calculation, input rules and interpretation.

When to use Card Grace Period Trailing Interest Checker

Use Card Grace Period Trailing Interest Checker when you need to evaluate the supplied records under the calculation and evidence rules below. No missing payment dates, compounding or issuer grace restoration is inferred.

Prepare observed financial records and verified caller terms. Use one currency for integer minor-unit money and preserve leading zeros in identifier text. One basis point is 0.01 percentage points. Resolve dates, local clocks, counting rules and evidence flags as specified.

How to use Card Grace Period Trailing Interest Checker and understand its results

Prepare observed financial records and verified caller terms. Use one currency for integer minor-unit money and preserve leading zeros in identifier text. One basis point is 0.01 percentage points. Resolve dates, local clocks, counting rules and evidence flags as specified.
Enter postStatementInterestBearingBalancesMinor, observedBinCivilDays, callerAnnualRateBasisPoints, callerAnnualDayBasis, callerGraceStillEligible using the field table and calculation rules, then run the tool.
Read modeledTrailingInterestMinor, interestBearingObservedDays, interestSuppressedByCallerGraceEvidence. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
postStatementInterestBearingBalancesMinor	Post statement interest bearing balances minor	list of number	Required
observedBinCivilDays	Observed bin civil days	list of number	Required
callerAnnualRateBasisPoints	Caller annual rate basis points	number	Required
callerAnnualDayBasis	Caller annual day basis	number	Required
callerGraceStillEligible	Caller grace still eligible	boolean	Required

Enter aligned nonempty nonnegative safe-integer balances and integer bin days 1–3660, integer annual basis points 0–100000, annual basis 1–366 and grace boolean. Accumulate exact integer exposure and round once. Return modeled interest, summed observed days and grace-suppression flag. Inputs remain validated when grace is true.

interest=graceEligible?0:roundMinor(sum(balance_i×days_i)×annualBps/(basis×10000))

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
modeledTrailingInterestMinor	Modeled trailing interest minor	number
interestBearingObservedDays	Interest bearing observed days	number
interestSuppressedByCallerGraceEvidence	Interest suppressed by caller grace evidence	boolean

json

{
  "input": {
    "postStatementInterestBearingBalancesMinor": [
      10000,
      5000
    ],
    "observedBinCivilDays": [
      2,
      3
    ],
    "callerAnnualRateBasisPoints": 3650,
    "callerAnnualDayBasis": 365,
    "callerGraceStillEligible": false
  },
  "output": {
    "modeledTrailingInterestMinor": 35,
    "interestBearingObservedDays": 5,
    "interestSuppressedByCallerGraceEvidence": false
  }
}

Limitations and assumptions

No missing payment dates, compounding or issuer grace restoration is inferred.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 10,000 entries; string lists to 128 strings of at most 128 characters each. The rules above may impose smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use Statement Cycle Grace Days Lookup: A statement grace window combines elapsed calendar days with separate qualification evidence. Its end date is included in the declared window. For a complementary task, use Cash Advance Immediate Interest Cost Calculator: Cash-advance cost can combine a minimum fee with immediate simple interest. Explicit fee financing determines the interest-bearing base.

References

Card Grace Period Trailing Interest Checker — tool.io

Similar or alternative tools

Statement Cycle Grace Days Lookup
A statement grace window combines elapsed calendar days with separate qualification evidence. Its end date is included in the declared window.
Cash Advance Immediate Interest Cost Calculator
Cash-advance cost can combine a minimum fee with immediate simple interest. Explicit fee financing determines the interest-bearing base.