Same market or a new one?

What you paid, plus major improvements (your tax basis). Improvements such as an addition or a new roof raise the basis; repairs do not.

Monthly loan payment today (principal and interest). Left out if you owe nothing.

Filing. The tax-free gain on a main home is US$250,000 single, US$500,000 married filing jointly (IRS Publication 523).

Lived in it as your main home 2 of the last 5 years?. Needed for the tax-free gain.

Your other income in the year of the sale, before tax. Without the sale. It sets which tax rate the gain falls into.

State. Sets the state tax on the gain and the property tax (that state’s median rate, Census 2024; 0.9% with no state).

Price of a home abroad. Bought for cash: US lenders do not lend on foreign homes and local loans for foreigners are limited.

Selling costs. Agents, fees and transfer taxes.

How the sale cash is worked out. The gain is taxed as a long-term gain with the 2026 federal rules: the gain above the tax-free amount sits on top of your other income after the standard deduction (US$16,100 single, US$32,200 joint) and is taxed at 0%, 15% or 20%; the 3.8% investment income tax applies to the smaller of the gain and your income over US$200,000 (single) or US$250,000 (joint). The state tax is the state’s income tax on your income with and without the gain; Washington’s capital gains tax leaves out real estate. Tax on a gain above the tax-free amount is the same whatever you buy next.

What each choice frees. Staying frees nothing. The gain only becomes money you can spend when the next home costs less, or when you rent. A negative figure is cash you would need from savings or a bigger loan. Shares above 100% include the equity you had before the price rose.

Housing costs after the move. Loan payment, property tax, insurance and upkeep, or rent. Property tax, insurance and upkeep are 2.90% of the value a year in the US (tax at the median rate of the state you chose, 0.9% with no state, plus insurance 0.5% and upkeep 1.5%) and 1.2% abroad. Costs of buying are 3% in the US and 8% abroad (taxes, notary and agent fees run 6% to 12% in Mexico, Spain and most of Latin America); moving costs are 1% of your sale price (3% abroad and for renting). Costs abroad vary by country: use the country pages. No new loan is modelled, and a negative amount is cash you would need from savings or a bigger loan.