Iran cut its enriched-uranium stockpile by about 98% under the 2015 deal, to below 300 kilograms. President Donald Trump pulled the U.S. out of the accord in 2018. This explainer summarizes what the JCPOA required, what Iran received, why Washington left, and how current talks extend beyond the original accord.

What the 2015 accord did

On July 14, 2015, Iran and a group of world powers signed the Joint Comprehensive Plan of Action (JCPOA). The agreement brought together the European Union and six major states — China, France, Russia, the United Kingdom, the United States, and Germany — after roughly two years of negotiations and work by hundreds of specialists.

  • Limits on uranium: Iran reduced its enriched-uranium stockpile by about 98 percent, to under 300 kilograms.
  • Enrichment cap: Enrichment was capped at 3.67 percent — suitable for civilian energy needs but far below weapons-grade levels.
  • Centrifuge restrictions: Iran’s installed centrifuge capacity was sharply reduced. Before the JCPOA, Iran operated about 20,000 centrifuges; the deal limited that number to a maximum of 6,104 machines, confined to two facilities and restricted to older-generation models.
  • Reactor changes: The Arak heavy-water reactor was redesigned so it could no longer produce plutonium suitable for weapons.
  • Inspections: The accord established an intrusive inspection and monitoring regime overseen by the International Atomic Energy Agency.

What Iran got in return

In exchange for the nuclear limits and inspections, Tehran received phased relief from international sanctions that had hurt its economy.

  • Frozen assets: The deal led to the release of billions of dollars in frozen assets.
  • Trade and banking: Limits on oil exports and banking were eased, allowing greater participation in global trade and finance.

For the deal’s participants, the JCPOA was a trade-off: increased transparency and longer timelines before Iran could reach a weapons capability in return for a phased rollback of punitive economic measures.

Why the U.S. left and what changed

President Donald Trump withdrew the United States from the JCPOA in 2018, calling the agreement "the worst deal ever." Washington then restored and expanded sanctions on Tehran, fracturing the international consensus around the pact and putting the U.S. at odds with other signatories that sought to preserve it.

Since the U.S. withdrawal, American officials have pushed for a broader package of limits. Public comments from President Trump say any new agreement would be "far better" than the 2015 deal. Washington’s stated demands before recent negotiations included additional curbs on nuclear activities plus limits on Iran’s ballistic-missile program and regional support for armed groups — issues the original JCPOA did not directly address. Those added conditions make any successor agreement more complex and politically sensitive.

Inspection and verification under the JCPOA

A central pillar of the 2015 accord was oversight. The International Atomic Energy Agency’s inspection regime gave international monitors routine access to Iran’s declared nuclear facilities, a level of monitoring the agency described as among the most intrusive it had ever seen.

Why this matters: The U.S. withdrawal and Washington’s push for a broader package — including limits on ballistic missiles and Iran’s regional support — have fractured the original international consensus and made any successor agreement more complex and politically sensitive. That shift is why current talks reach beyond the JCPOA’s original nuclear-only limits.

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The key question now: will negotiators restore the JCPOA's nuclear limits alone, or insist on the broader package — including missile and regional curbs — that Washington has pressed for?