US–Spain cross-border inheritance & estate tax

When an estate or lifetime gift touches both the United States and Spain, two tax systems can reach the same assets. Here is how each one works in 2026, how double taxation is relieved, and the traps that most often catch cross-border families.

Reflects 2026 rules · an estimate, not advice.

Who is taxed on worldwide assets?

Both countries tax some people on their worldwide estate and others only on assets located there. Get that classification wrong and every number is wrong.

The US side — 2026 figures

• Citizens & domiciliaries are taxed on their worldwide estate and gifts; non-resident aliens only on US-situs assets (US real estate, US company shares, tangible US property). US bank deposits and life insurance are exempt (IRC §2105).
• $15,000,000 unified estate & gift exemption per person; 40% top rate on the excess.
• Portability (DSUE) lets a surviving spouse carry a predeceased spouse's unused exemption — up to a combined $30M — for estate and gift tax (not GST).
• $19,000 annual gift exclusion per recipient; NRAs get only a $60,000 exemption-equivalent (~$13k credit) absent treaty relief.
• 16 US states plus DC levy their own death taxes on top of the federal tax.

The Spain side — 2026 figures

• Inheritance & gift tax (ISD) is national but heavily modified by the deceased's Autonomous Community: Madrid, Andalucía, Valencia and others grant close family ~99% relief; some (e.g. Asturias) tax in full.
• The state scale runs 7.65%–34%, multiplied by a coefficient for kinship and pre-existing wealth.
• Setting the correct Autonomous Community is the single biggest driver of the Spanish figure.
• País Vasco and Navarra use their own foral schedules.

Relieving double taxation

There is no US–Spain estate-tax treaty — relief comes only from unilateral foreign-tax credits, so double taxation must be planned around carefully. This makes getting the Spanish Autonomous-Community treatment and the US credit right especially important.

The traps that catch US–Spain families

• Situs of shares. Shares in a US company are US-situs for a non-resident alien even if held through a foreign broker — a common six-figure surprise.
• The non-citizen spouse. The unlimited US marital deduction does not apply to a non-US-citizen spouse without a QDOT.
• Double filing. A US person's foreign estate can still owe US Form 706; a large gift/bequest from a foreign person to a US recipient can trigger US Form 3520.

See your own numbers

HeirCalc models the US and Spain sides together — applying the exemptions, residence and situs rules and any treaty relief — and shows the exposure in each country with the statutory reason behind every figure. It runs entirely in your browser; nothing is saved or sent anywhere.

This guide is general information for 2026, not legal, tax, or financial advice. Cross-border estate and gift tax turns on precise facts — residence, domicile, situs, treaty positions, trusts and forced-heirship rules — that can change the outcome. Confirm your situation with a qualified cross-border professional. HeirCalc is an estimator by Krometis Analytics.