Installment Sale Calculator (Form 6252) 2026

What Is an Installment Sale (Form 6252)?

An installment sale, reported on IRS Form 6252, is a sale of property where the seller receives at least one payment after the year of sale. Section 453 of the Internal Revenue Code lets the seller defer capital gains tax across the years payments are received instead of recognizing the entire gain in the year of sale. Common uses include seller-financed real estate, business buyouts, and family-to-family asset transfers. The installment method is mandatory unless you elect out on a timely-filed return. Source: IRS Publication 537.

Each year you receive a payment, the principal portion is split into return of basis (tax-free) and gain (taxable). The percentage that is gain — the gross profit percentage — is fixed at the start of the contract: gross profit ÷ contract price. So if your gross profit is 60% of the contract price, then 60 cents of every dollar of principal received is taxable gain. Stated interest is reported separately each year as ordinary interest income. Last updated: May 3, 2026.

How the Calculation Works in 2026

Form 6252 follows a fixed sequence: (1) selling price minus selling expenses minus adjusted basis minus depreciation recapture = gross profit; (2) gross profit ÷ contract price = gross profit percentage; (3) principal received in the year × gross profit percentage = installment sale income for the year. Depreciation recapture under IRC § 1245 (personal property) and § 1250 (real estate) is fully recognized in the year of sale at ordinary rates — it is not deferred under the installment method. This is the most common surprise for sellers of rental real estate or depreciated business assets, who often assume the entire tax bill spreads evenly.

The tool above runs the IRS Pub 537 sequence: it deducts recapture from gross profit before computing the installment percentage, taxes recapture at your ordinary rate in Year 1, and then applies your long-term capital gains rate (0/15/20%) plus 3.8% NIIT (if applicable) to the deferred portion across the contract term. It also shows imputed interest at the AFR you supply — the minimum stated rate the IRS accepts under IRC § 1274 / § 7872.

When Installment Sales Are a Good Tax Strategy

Spreading gain across multiple tax years is most valuable when (a) the seller would jump from a 15% LTCG bracket to 20% or trigger NIIT in the year of sale, (b) the seller has a one-time income spike (sale of a business, retirement) and expects lower brackets in future years, or (c) the seller wants ongoing interest income at AFR rates from a buyer they know and trust. Real estate flippers and dealers cannot use the installment method — it is restricted to investment, personal, and business property held for productive use. Publicly traded stock is also ineligible.

Watch for the pledge rule: if you pledge the installment note as collateral for a loan exceeding $150,000 of contract price, the loan proceeds are treated as a payment, accelerating the gain. Also watch the related-party second-disposition rule — if a related-party buyer resells the property within two years, your full deferred gain accelerates immediately. Form 6252 Part III handles related-party reporting.

Imputed Interest and the Applicable Federal Rate (AFR)

If the installment contract states no interest, or interest below the applicable federal rate (AFR), the IRS will impute interest under IRC § 1274 and § 7872. Imputed interest reclassifies a portion of each principal payment as interest income, which is taxed at ordinary rates and shrinks the capital gain. The AFR is published monthly by the IRS — short-term (≤3 years), mid-term (3–9 years), and long-term (>9 years) rates apply based on the contract length. For 2026, mid-term AFRs are roughly in the 4.0–4.5% range; check the latest IRS Revenue Ruling for the month your contract is signed. Charging at least the AFR avoids imputed interest and keeps your gross profit percentage clean.