The concept: A tax deduction doesn't eliminate the cost — it reduces it by your marginal rate.
A 7% mortgage in the 24% bracket effectively costs 5.32% after-tax. This is how you compare
mortgage debt to other investments on an apples-to-apples basis.
After-Tax Rate = Mortgage Rate × (1 − Tax Bracket)
Only applicable when the client is itemizing and their mortgage interest qualifies for the deduction. Always refer to a CPA.
Your Inputs
Mortgage Interest Rate
%
Marginal Tax Bracket
Federal income tax bracket (2025)
Loan Balance For monthly savings display
$
Results
Tax Rate Multiplier
0.78
After-Tax Rate
5.46
%
Annual Interest (gross)
$
28,000
Annual Tax Savings
$
6,160
True Monthly Cost (after-tax)
$
1,820
⚠ Standard deduction check: With a $400,000 balance at 7%, annual mortgage interest is ~$28,000. If property taxes + mortgage interest < $30,000 (MFJ), the client may be taking the standard deduction — meaning no itemized benefit. Confirm with their CPA before presenting the after-tax rate.
The concept: When a client needs cash from a retirement account, they can't just pull the net
amount — the withdrawal is taxed as income. To net $100,000 in the 22% bracket, they must withdraw
$128,205. If they're under 59½, add the 10% penalty on top.
Gross Withdrawal = Net Needed ÷ (1 − Tax Bracket)
Your Inputs
Net Amount Needed What the client actually wants to receive
$
Marginal Tax Bracket
Client Age
Account Type
Withdrawal Math
Income Tax Rate Applied
22%
Early Withdrawal Penalty
None
Combined Rate (tax + penalty)
22%
Effective Multiplier
0.78
Taxes & Penalties Paid
$
28,205
IRA First-Time Homebuyer Exception
Up to $10,000 from a Traditional IRA may be withdrawn penalty-free for a first-time home purchase.
No penalty (10%) applies, but income tax still applies. Applies to buyer, spouse, children, grandchildren, or parents. Client must not have owned a principal residence in the prior 2 years.
401(k) note: No first-time buyer exception, but client may take a loan up to $50,000 and repay with interest — to themselves.
Quick Calc — $10k IRA Exception
Gross withdrawal to net $10,000 (tax only, no penalty)
$
12,821