To gross up non-taxable income for a mortgage, a lender multiplies the tax-free amount by 1.25, which converts it into the pre-tax equivalent a wage earner would need to take home the same money. A borrower receiving $2,000 a month in tax-free Social Security disability gets credit for $2,500 in qualifying income. The formula is simple. What catches borrowers off guard is proving the income is actually non-taxable, proving it will keep coming, and knowing which slice of a mixed benefit qualifies.
Income That Qualifies
Any income not reduced by federal income tax is a candidate. The common sources lenders see:
- Social Security retirement, survivor, or disability benefits, but only the portion that is not taxable.
- Disability insurance from private policies or government programs when premiums were paid with after-tax dollars. Workers’ compensation falls here too.
- Child support paid under a court order.
- Public assistance and foster care payments.
- Military Basic Allowance for Housing, subsistence, and clothing allowances. Taxable military pay such as flight, hazard, and combat pay does not qualify.1Veterans Benefits Administration. Grossing Up
- A minister’s designated housing allowance, capped at the lesser of the designated amount, what was actually spent on housing, or the home’s fair rental value.2Internal Revenue Service. Ministers’ Compensation and Housing Allowance
- Alimony received under agreements executed after December 31, 2018. Older agreements followed rules that made alimony taxable to the recipient, so those payments do not qualify.
Pension income, 401(k) distributions, and traditional IRA withdrawals are taxable and get counted at face value. Qualified Roth IRA distributions are tax-free and can be grossed up if they meet the continuity and documentation standards below.
The Math
Multiply your verified non-taxable income by 1.25. If you receive $2,000 a month in non-taxable Social Security disability and $800 in child support, those become $2,500 and $1,000 respectively, for $3,500 in qualifying income instead of $2,800.3Fannie Mae. General Income Information
The 25% figure is a floor. If the federal and state tax a wage earner in a similar bracket would actually pay exceeds 25%, your lender can use the higher percentage.3Fannie Mae. General Income Information Most lenders stick with 25% because it avoids a bracket analysis, but borrowers in high-tax states can ask for the actual rate.
Partially Taxable Social Security
Up to 85% of your Social Security benefits can be taxable depending on your total income. Only the untaxed slice gets grossed up. If you receive $1,800 a month and your tax return shows $1,200 of that was taxable, only the remaining $600 is multiplied by 1.25, adding $150 to your qualifying income. The $1,200 taxable portion counts at face value. The lender uses your tax return to find the split, so pull your SSA-1099 before applying and work out the numbers yourself.
How the Rules Differ by Loan Program
Every major mortgage program allows grossing up, but the fine print differs enough to matter.
Conventional (Fannie Mae and Freddie Mac)
Fannie Mae permits a 25% gross-up on verified non-taxable income when the income and its tax-exempt status are likely to continue, and allows a higher percentage where the actual tax burden would be greater.3Fannie Mae. General Income Information Freddie Mac takes the same 25% approach.4Freddie Mac. Freddie Mac Seller/Servicer Guide
FHA
FHA Handbook 4000.1 allows the 25% gross-up, with one strict wrinkle: if the documentation showing tax-exempt status is set to expire within three years of your mortgage application date, the income cannot be counted at all.5HUD. FHA Single Family Housing Policy Handbook 4000.1 Income with no defined expiration date is generally treated as continuing.
VA
The VA does not set a fixed percentage. Lenders use tax tables to determine a reasonable gross-up margin, commonly between 15% and 25%.6Veterans Benefits Administration. Loan Origination Reference Guide Veterans with only non-taxable income often see something closer to 15%, reflecting the lower effective rate at that income level.
USDA
USDA guaranteed loans allow a 25% gross-up on income not subject to federal taxes when calculating repayment income.7USDA Rural Development. HB-1-3555, Chapter 9 – Income Analysis The same documentation and continuity standards apply.
The Three-Year Continuity Rule
Grossing up only helps if the lender believes the income will keep arriving. The standard is that non-taxable income must be expected to continue for at least three years from the note date on conventional loans.8Fannie Mae. Alimony, Child Support, Equalization Payments, or Separate Maintenance FHA measures from the application date instead.5HUD. FHA Single Family Housing Policy Handbook 4000.1 That difference matters when months pass between application and closing.
Social Security retirement and permanent disability payments have no expiration, so they clear the test automatically. Public assistance income without a defined end date is generally treated as ongoing. Child support and alimony are harder. The lender will check your child’s age and the terms of the order. If your youngest turns 18 in two years, child support fails the three-year test and may not be counted at all, let alone grossed up.
Award letters with upcoming review dates get extra scrutiny. If your disability benefit is up for review before the three-year window closes, the underwriter may decline to count it. An updated letter confirming the benefit timeline before you apply can be the difference between approval and denial.
What to Document Before You Apply
Lenders need proof of two things: that you receive the income and that it’s non-taxable. Gather these in advance.
Benefit and award letters. For Social Security, request a benefit verification letter from your my Social Security account.9Social Security Administration. Get Benefit Verification Letter Workers’ compensation award letters must show the date of injury, current payment amount, type of payment (temporary, permanent, partial, or total), and payment frequency; if benefits have ended, the last payment date and amount.10Social Security Administration. Proof of Workers’ Compensation And/Or Similar Benefits Private disability carriers issue comparable documentation.
Court orders. Child support and alimony require a fully executed court order or legal separation agreement showing the amount, schedule, and duration. The lender will also want to see that payments are actually arriving, so bank deposits matter as much as the order.
Tax returns or transcripts. Your federal return is the primary tool for verifying what was and wasn’t taxable, especially the split on Social Security benefits. Lenders often pull IRS transcripts directly, which the IRS notes “usually meets the needs of lending institutions offering mortgages.”11Internal Revenue Service. Transcript Types for Individuals and Ways to Order Them Expect to provide two years.
Bank statements. Lenders look for 12 months of consecutive statements to confirm payments arrive on schedule and match the amounts in your award letters or court orders.12Fannie Mae. Verification of Deposits and Assets
Mistakes That Shrink Your Qualifying Income
The most common error is failing to mention non-taxable income at all. If your loan officer doesn’t ask about Social Security, disability, or child support, raise it yourself. Leaving tax-free income off the application makes your debt-to-income ratio look worse than it is.
Second is applying the 25% gross-up to a full Social Security check when part of it is taxable. Underwriters catch this immediately and the recalculation can delay or kill the deal.
Third is incomplete or stale documentation. An award letter with no expiration date works in your favor. An expired letter you haven’t refreshed causes the income to be excluded entirely. The same risk applies to child support orders that have been modified since the original filing but never updated in your file.
Working out which of your income streams qualify, which part of each is actually non-taxable, and whether each will last three years before you sit down with a lender puts you in a far stronger position than discovering the answers during underwriting.