Dax Function: EFFECT

Category: Financial Functions

The EFFECT function in Power BI is a DAX (Data Analysis Expressions) function that calculates the effective annual interest rate given a nominal annual interest rate and the number of compounding periods per year.

Purpose

  • To convert a nominal annual interest rate to its effective equivalent, considering the compounding frequency.

  • Helps in comparing interest rates that have different compounding periods.

Type of Calculations

  • Computes financial values related to interest rate equivalency.

  • It performs calculations using exponential formulas to account for periodic compounding.

Practical Use Cases

  • Loan Comparisons: Compare loan offers with different nominal interest rates and compounding frequencies.

  • Investment Analysis: Assess the actual return of financial products with periodic compounding.

  • Financial Planning: Calculate effective rates for mortgages, savings, and credit cards.


EFFECT(nominal_rate, npery)
 
ParameterTypeDescription
nominal_rateScalarThe nominal annual interest rate, expressed as a decimal (e.g., 5% = 0.05).
nperyScalarThe number of compounding periods per year (e.g., 12 for monthly, 4 for quarterly).

How Does EFFECT Dax Function Works

Formula

The EFFECT function calculates the effective annual interest rate using the formula:

Where:

  • rnominal​ : Nominal annual interest rate

  • n: Number of compounding periods per year

Logical Flow

  1. The nominal rate is divided by the number of compounding periods.

  2. The result is raised to the power of the number of compounding periods.

  3. Subtract 1 to get the effective annual rate.

What Does It Return?

  • Returns the effective annual interest rate as a scalar value.

  • The result is expressed as a decimal (e.g., 0.0512 for 5.12%).

When Should We Use It?

  • Interest Rate Comparisons: Evaluate the true cost of borrowing or the actual yield of investments.

  • Effective Rate Calculation: Transform nominal rates for use in advanced financial modeling.

  • Personal Finance: Assess credit card rates, mortgage APRs, or savings account returns.

Examples

Basic Usage :

Calculate the effective annual rate for a nominal rate of 5% compounded monthly (12 periods per year):


EFFECT(0.05, 12)

Result: 0.05116 (5.116%)

Column Usage

Apply the EFFECT function to a table of loan details to calculate the effective rate for each row:


EffectiveRate = EFFECT(Table[NominalRate], Table[CompoundingPeriods])

Calculates the effective annual interest rate for each loan.

Advanced Usage

Combine the EFFECT function with other DAX functions for more complex financial scenarios. For example, calculate the total effective rate for multiple loans:


TotalEffectiveRate =
SUMX(
Loans,
EFFECT(Loans[NominalRate], Loans[CompoundingPeriods])
)

Sums the effective rates of all loans in a dataset.

Tips and Tricks

  • Use decimals for the nominal_rate parameter to ensure accuracy.

  • Cross-check the compounding frequency (npery) with the terms of the financial product.

  • Do not confuse the nominal rate with the effective rate; they represent different concepts.

  • Ensure that npery is greater than 0 to avoid calculation errors.

Performance Impact of EFFECT DAX Function:

  • Efficient for scalar values or small datasets.

  • May slow performance when applied to very large tables row-by-row.

Related Functions You Might Need

FunctionDescription
NOMINALConverts an effective annual rate to a nominal rate given a compounding frequency.
PVCalculates the present value of a series of cash flows.
FVDetermines the future value of an investment with periodic payments.
RATEReturns the interest rate for an annuity.

Want to Learn More?
For more information, check out the official Microsoft documentation for EFFECT You can also experiment with this function in your Power BI reports to explore its capabilities.

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1. What does the EFFECT function do?

The EFFECT function calculates the effective annual interest rate from a nominal rate and the number of compounding periods per year.

2. How is the EFFECT function used in financial modeling?

It converts nominal rates to effective rates for accurate comparisons of financial products with different compounding periods.

3. Can I use the EFFECT function with tables?

Yes, you can use the EFFECT function in calculated columns or measures to apply it to table data.

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