The After Deduction Rate Estimator measures the percentage of an original amount removed by deductions and the percentage retained afterward. It accepts either the final amount after deductions or the deduction amount, making it useful when only one of those values is known.
The result can help compare fees, payroll reductions, discounts, taxes, or benefit offsets on a common percentage basis. It describes the entered amounts only and does not identify whether the deductions are valid or correctly classified.
Use the amount before deductions; it must be greater than zero.
Use the final amount when known.
When this field is above zero, it is used to calculate the rate and retained amount.
The main result is the deduction rate; the breakdown includes the complementary retention rate.
The deduction amount is limited to the range from zero to the original amount.
The main result is the share of the original amount removed by the deduction amount used.
When a known deduction is entered, the difference check shows whether it agrees with the entered after-deduction amount.
Given: Original amount = $5,000; after-deduction amount = $4,100; no separate known deduction.
Calculation: Deduction = $5,000 − $4,100 = $900. Deduction rate = $900 ÷ $5,000 × 100 = 18%. Retention rate = 82%.
Result: The estimated deduction rate is 18%.
A positive known deduction takes priority. The calculator then derives the retained amount and compares it with the after-deduction amount you entered.
It can be entered, but without a known deduction the calculated deduction is limited to zero because an increase is not a deduction.
A percentage rate cannot be calculated when the denominator is zero.
Yes in this simple model. The two rates sum to 100%.
This measures all entered deductions as a share of the original amount. An effective tax rate normally isolates tax relative to a defined income base.