Make the numbers
mean something.

We convert the assumed effective annual return and annual fee into a monthly growth factor: ((1 + return) × (1 − fee))^(1/12). Each month the prior balance grows and the contribution is added at month-end. Contributions stay fixed in nominal dollars. The low and high cases change the annual return by your selected range; they are not probability bounds.

Today’s purchasing power divides the ending balance by (1 + inflation)^years. The delay case holds the starting balance unchanged outside this investment until the delay ends; contributions also begin later. The displayed gap therefore includes missed contributions as well as investment growth. Taxes, changing returns, withdrawals and transaction costs are not modeled.

Both scenarios use the same starting balance, monthly contributions, duration and gross return. Only the annual asset-based fee changes. The fee is modeled as a multiplicative annual factor converted to monthly compounding, not as a broker’s exact billing schedule.

The difference in ending balances includes modeled fees and the growth displaced by those fees. It is not the sum of fees charged. Trading costs, taxes, performance fees, loads and flat subscriptions are excluded.

The model divides a hypothetical portfolio loss budget by entry price minus stop price plus an extra per-share loss allowance. It rounds down to whole shares and caps the position at the shares affordable using the available cash.

This is a planned-loss calculation, not a maximum-loss guarantee. Stops may fill at a worse price or not execute as expected; gaps can exceed the allowance. Commissions and taxes are excluded. This model does not support short sales, leverage, options or futures. The risk percentage is your assumption, not a recommended size.

Your three target percentages must total 100%. Full-rebalance differences equal each target value at the post-contribution total minus the current holding. Positive values represent purchases; negative values represent sales.

For the cash-only illustration, new contributions are divided proportionally among positive dollar shortfalls. Existing holdings are not sold, so the result may not match your target. Minimum new cash for exact targets without selling is max(current value ÷ target weight) minus current total. A nonzero holding with a 0% target cannot reach that target through finite contributions alone. Taxes, spreads, trading fees and market movements are excluded.