Investment Fee Drag Method, Formula & Examples
On this page
This method guide explains the calculation sequence behind the Investment Fee Drag Calculator. It owns formulas, input definitions, timing, rounding and reference checks; the calculator remains the only page that performs the numeric scenario.
Calculation sequence
Both scenarios use identical contributions and gross return. The entered annual fee is subtracted from the gross scenario, converted to a monthly equivalent and compounded across the same months.
Inputs and evidence
Use current written documents for every material input. The calculator supports: Market and currency, Initial investment, Monthly contribution, Gross annual return, Scenario A annual fee, Scenario B annual fee, Time horizon.
Reference example
With 100,000, no contributions and zero gross return, two zero-fee scenarios both remain 100,000. Change only one fee to isolate its modeled drag.
Boundary and error checks
Test zero-rate branches where available, minimum and maximum supported inputs, and a scenario in which the main result reverses. Reject blank, non-finite or out-of-range values rather than silently substituting them.
Model boundary
Subtracting fee from gross return is a planning approximation. Real fees can post at different times and taxes, trades, cash flows and performance vary.
Sources and review status
- Investor.gov — Compound Interest Calculator
- Investor.gov — How Fees and Expenses Affect Your Investment Portfolio
- Investor.gov — Real Return
Sources and model boundaries checked 2026-10-08. This new opportunity-map expansion has automated formula, fixture and source QA but has not been represented as human editorial review. Keep the route noindex until CalculatorGeek records a completed YMYL editorial review.