The method of how they calculated to trade imbalances has been well publicised.
Childish in its simplicity but it is as follows.
10% tariffs was the default level which was imposed even on countries such as Australia which has a trade deficit favouring USA.
For the rest it is explained as follows:
"There was no explanation given for how each country’s “tariffs charged to the USA” were calculated. Boffins on the outside quickly worked it out: the number is just the 2024 US trade deficit with that country divided by the US’s imports from that country.
For example, in 2024, the US trade deficit with China was $US295.4 billion ($469 billion). US imports from China were $US438.9 billion. Dividing the deficit by the imports equals 67 per cent, which is the exact figure shown next to “tariffs charged to the USA” on Trump’s chart.
It’s the same for Thailand, Indonesia, the European Union, the Philippines, Israel, Japan and every other country this masthead has checked so far. "
You then divide by two for today's tariff imposition