Real Estate Gift Tax Calculator

Quick summary

Gifting real estate is one of the most common wealth-transfer moves — and one of the most misunderstood. The Real Estate Gift Tax Calculator handles three IRS rules at once: gift tax exposure, recipient basis, and donor gain on assumed mortgages.

It applies the $19,000 annual exclusion per donee ($38,000 with gift-splitting), the $15 million OBBBA-permanent lifetime exclusion, the net-gift treatment for assumed mortgages (FMV minus mortgage = taxable gift portion), the carryover-basis rule of IRC §1015 (recipient inherits donor's original cost basis — no step-up), and the Diedrich rule that triggers donor capital gain when the assumed mortgage exceeds donor's basis.

Bottom line: gifting a $500K rental with a $200K mortgage and $150K basis to your child is NOT just a $500K gift. The $200K mortgage assumed = $50K phantom gain to YOU, plus the recipient takes your $150K basis (no step-up), creating a future capital gains time bomb on the appreciation.

Property FMV (qualified appraisal)

Donor adjusted basis

Mortgage balance assumed by donee

Mortgage assumed = treated as part-sale; if mortgage exceeds donor basis, donor recognizes gain (Diedrich rule)

Recipient

Donor filing status

Gift-splitting with spouse?

Prior taxable gifts (post-1976)

Reduces remaining $15M lifetime exclusion

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How to use

1 Enter property fair market value at gift date (qualified appraisal STRONGLY recommended for IRS substantiation, especially over $1M).
2 Enter your adjusted basis in the property (purchase price + capital improvements - depreciation taken).
3 Enter any mortgage balance the recipient will assume — this triggers net-gift treatment (taxable portion = FMV - mortgage).
4 Choose recipient (US-citizen spouse = unlimited; non-citizen spouse = $194K exclusion; other = $19K). Enter prior taxable gifts.
5 Click Calculate to see net gift amount, taxable gift after exclusion, lifetime exclusion remaining, federal gift tax owed, recipient's carryover basis, and any Diedrich rule donor gain on the mortgage assumption.

Real Estate Gift Tax — The Three Hidden Layers

Layer	What It Means	2026 Rule
1. Gift tax exposure	Tax on the transfer to donor (rare in practice)	$19K annual + $15M lifetime exclusion (OBBBA)
2. Recipient basis	Cost basis recipient uses for future sale	Carryover from donor (IRC §1015) — no step-up
3. Donor mortgage gain	Phantom gain if assumed mortgage > basis	Diedrich v. Comm'r — net-gift portion is sale

Carryover vs. Stepped-Up Basis — The Biggest Gift-vs-Inherit Decision

This is the single most important number when planning generational property transfers.

Scenario	Recipient Basis	Effect
Gift during your lifetime (IRC §1015)	Carryover from donor	Recipient inherits ALL appreciation as future taxable gain
Inherit at death (IRC §1014)	Stepped up to FMV at date of death	All pre-death appreciation NEVER taxed
Sell to family at FMV	FMV (purchase price)	You recognize gain now; family gets clean basis

Tax calculation example: Property bought for $200K, now worth $1M. Gifted to child → child sells for $1M → taxable gain $800K. Inherited at death (FMV $1M) → child sells for $1M → $0 taxable gain. The step-up at death often saves $160K-$300K in capital gains tax.

The Net-Gift / Diedrich Rule for Mortgaged Property

If you gift property and the recipient assumes the mortgage, the IRS treats the transfer as part-sale, part-gift:

Component	Treatment
FMV minus mortgage	Net gift (subject to gift tax exclusion)
Mortgage balance assumed	Treated as sale proceeds to donor
If mortgage > donor's basis	Donor recognizes capital gain on the excess (Diedrich v. Commissioner, 457 U.S. 191)
If mortgage ≤ donor's basis	No donor gain — recipient takes carryover basis reduced by mortgage

Smart Gift Strategies for Real Estate

Strategy	Why It Works
Annual exclusion fractional gifts	Gift undivided 1/X interest each year — uses $19K exclusion repeatedly
QPRT (Qualified Personal Residence Trust)	Discount value of remainder gift, retain residence rights
GRAT with real estate	Gift appreciation only, retain annuity payment for years
Sale to IDGT (Intentionally Defective Grantor Trust)	Sell for note — freezes value at sale, no recognized gain
Split-interest gifts (CRT)	Charitable Remainder Trust gives income stream, charity gets remainder

Form 709 Filing Requirements

Form 709 is REQUIRED when you gift real estate above the $19,000 annual exclusion (per donee), elect gift-splitting with spouse, or transfer fractional interests. Filed by April 15 of the year following the gift. Qualified appraisal recommended for any real estate gift over $250,000 — IRS audits property valuations more aggressively than cash gifts.

FAQ

Q How much real estate can I gift tax-free in 2026?

Up to $19,000 per recipient per year, or $38,000 with gift-splitting (married filing jointly with consent on Form 709). Above that, the excess uses your $15 million lifetime exclusion before any actual tax is due. Most donors never owe gift tax — but Form 709 is still required.

Q What is carryover basis on gifted real estate?

Recipients of gifted property inherit the donor's original cost basis (IRC §1015) — NOT the FMV. If you bought a house for $200K and gift it when worth $1M, your child takes the $200K basis. When they sell, gain is calculated from $200K. This is the opposite of inherited property which gets a step-up at death.

Q What happens if the recipient assumes my mortgage?

The transfer becomes "part-sale, part-gift." The mortgage portion is treated as sale proceeds. If the mortgage exceeds your adjusted basis, you (the donor) recognize CAPITAL GAIN on the excess under the Diedrich rule (Diedrich v. Commissioner). Net gift = FMV minus mortgage assumed.

Q Should I gift my house now or leave it to heirs?

Generally, leaving it at death is more tax-efficient because of the IRC §1014 step-up in basis — heirs get FMV at death as their cost basis, eliminating all pre-death appreciation gains. Gifting during life only makes sense for: (1) Medicaid planning, (2) using up lifetime exclusion before sunset, (3) removing future appreciation from estate.

Q Do I need an appraisal to gift real estate?

Yes — qualified appraisal is strongly recommended (effectively required) for any real estate gift over the $19K annual exclusion, especially over $250,000. Required documentation under §6695A. The IRS aggressively challenges undervaluations on gift returns. Use a USPAP-credentialed appraiser.

Q Can I gift a fractional interest in property?

Yes — gifting an undivided interest (e.g., 1/10 of a beach house each year) lets you use the $19K annual exclusion repeatedly. IRS allows valuation discounts of 15-30% for fractional interests due to lack of marketability and lack of control — making this a powerful generational transfer technique.

Q What if I want to gift real estate to my non-citizen spouse?

Special $194,000 annual exclusion (2026) applies to gifts to a non-citizen spouse — the unlimited marital deduction does NOT apply. Above $194K, gift uses your $15M lifetime exclusion. Solution for large transfers: Qualified Domestic Trust (QDOT) which preserves marital tax benefits.

Q When is Form 709 required for a real estate gift?

When (a) you gift real estate worth more than $19,000 to one person in 2026, OR (b) you elect gift-splitting with spouse, OR (c) you gift to a non-citizen spouse over $194,000. Filed by April 15, 2027 with your income tax return. Extensions: Form 4868 extension automatically extends Form 709.