The Trump administration took that formula’s figure, -0.5 for South Korea, and divided it by two to calculate the U.S. “discounted reciprocal” tariff rate. So, while South Korea imposes an effective tariff rate of .79 percent on U.S. goods, the reciprocal tariff rate the U.S. is imposing on South Korea is 25 percent.

President Donald Trump is scheduled to announce significant tariffs on other countries in a speech Wednesday afternoon at the White House.

More than a dozen countries set for US reciprocal tariffs spent the first day of President Donald Trump's tariff rollout not only bracing for the economic fallout but with confusion about exactly what rates they might face.