COPENHAGEN, April 3 (Reuters) - Danish jeweller Pandora said on Thursday it estimates the total impact of U.S. tariffs on the company to be around 1.2 billion Danish crowns ($178.34 million) per year, before any mitigating actions by the company.

Pandora's share price plunged 12% on Thursday to a 15-month low after U.S. President Donald Trump hiked duties on imports from a wide range of countries, including a 37% tariff on Thailand, where the company owns two factories producing most of its charm bracelets and other jewellery.

Pandora, whose single biggest market is the U.S., accounting for 31% of revenue last year, said the impact from tariffs set to take effect on April 5 and April 9 would be an estimated 700 million crowns in 2025.

Pandora said it is considering price hikes and changes to its supply chain to mitigate the impact, and expects to be able to fully mitigate 250 million crowns linked to goods eventually sold in Canada and Latin America but distributed via the U.S.

"Pandora will be monitoring the development closely, including discussions between the U.S. and countries impacted by the tariffs," the company said. ($1 = 6.7288 Danish crowns) (Reporting by Louise Breusch Rasmussen, editing by Terje Solsvik and David Evans)