Net Interest Margin NIM Calculator
Compute realized annualized NIM from actual income/expense and day-weighted earning-asset balance bins, preserving negative spread; bins must cover caller income period, no end-balance substitution, compounding or profit forecast.
Description
Net interest margin (NIM) uses net interest income over time-weighted earning assets.
Net interest margin (NIM) uses net interest income over time-weighted earning assets. Annualizing by the represented period differs from using an end balance.1
The returned values include Period net interest income minor, Observed period days, Time weighted average earning assets minor, Annualized observed nim percent. The How section below explains the calculation, input rules and interpretation.
When to use Net Interest Margin NIM Calculator
Use Net Interest Margin NIM Calculator when you need to evaluate the supplied records under the calculation and evidence rules below. No compounding, end-balance substitution or profit forecast is supplied.
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 Net Interest Margin NIM Calculator 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 periodInterestIncomeMinor, periodInterestExpenseMinor, earningAssetBalanceBinsMinor, earningAssetBinDays, callerAnnualDayBasis using the field table and calculation rules, then run the tool.
- Read periodNetInterestIncomeMinor, observedPeriodDays, timeWeightedAverageEarningAssetsMinor, annualizedObservedNimPercent. 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 |
|---|---|---|---|
| periodInterestIncomeMinor | Period interest income minor | number | Required |
| periodInterestExpenseMinor | Period interest expense minor | number | Required |
| earningAssetBalanceBinsMinor | Earning asset balance bins minor | list of number | Required |
| earningAssetBinDays | Earning asset bin days | list of number | Required |
| callerAnnualDayBasis | Caller annual day basis | number | Required |
Enter nonnegative safe-integer income, expense and aligned nonempty earning balances, integer bin days 1–3660 and annual basis 1–366. Require positive weighted average and checked integer sums. Return signed net income, represented days, weighted average and signed annualized percent. Bins must cover the income period by caller verification.
average=sum(balance_i×days_i)/sum(days); NIM%=100×(income−expense)/average×annualDayBasis/sum(days) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| periodNetInterestIncomeMinor | Period net interest income minor | number |
| observedPeriodDays | Observed period days | number |
| timeWeightedAverageEarningAssetsMinor | Time weighted average earning assets minor | number |
| annualizedObservedNimPercent | Annualized observed nim percent | number |
{
"input": {
"periodInterestIncomeMinor": 100,
"periodInterestExpenseMinor": 30,
"earningAssetBalanceBinsMinor": [
1000,
2000
],
"earningAssetBinDays": [
30,
60
],
"callerAnnualDayBasis": 360
},
"output": {
"periodNetInterestIncomeMinor": 70,
"observedPeriodDays": 90,
"timeWeightedAverageEarningAssetsMinor": 1666.6666666666667,
"annualizedObservedNimPercent": 16.799999999999997
}
}Limitations and assumptions
No compounding, end-balance substitution or profit forecast is supplied.
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.
Alternative or Complementary methods
Use Weighted Cost Of Funds Blended Calculator: Blended funding cost weights nominal annual rates by observed balances. Rounding once on the pooled numerator differs from rounding each funding line. For a complementary task, use Merchant Discount Effective Rate Calculator: Realized merchant discount compares observed processing fees with sales net of refunds. Other settlement deductions need a different denominator.
References
-
Net Interest Margin NIM Calculator — tool.io
Similar or alternative tools
- Weighted Cost Of Funds Blended Calculator
Blended funding cost weights nominal annual rates by observed balances. Rounding once on the pooled numerator differs from rounding each funding line.
- Merchant Discount Effective Rate Calculator
Realized merchant discount compares observed processing fees with sales net of refunds. Other settlement deductions need a different denominator.