A 'hard' Brexit would leave EU states with £8 billion a year higher tariffs than the UK, says a new report.
Busineses from the European bloc would add almost £13 billion a year in costs to their exports if the UK left the customs union without an alternative free trade deal with the bloc.
UK companies on the other hand would face a significantly lower £5.2 billion bill for sales to the other 27 states.
According to the analysis by the Civitas think tank, Theresa May could use the balance of trade to her advantage, during negotiations.
On a country-by-country basis, 22 of the 27 remaining EU members would see additional tariffs on exports to the UK than what UK firms would be hit by on sales to those individual nations.
German firms alone would bear £3.4 billion by way of tariff costs if the relationship between the EU and UK fell back on World Trade Organisation's (WTO) most-favoured nation rules.
In contrat, UK exporters would pay just £0.9 billion of tariffs on goods going to Germany.
The study further pointed out that French exporters could be hit with £1.4 billion in tariffs on their products as against UK exporters facing £0.7 billion.
Brexit supporters had argued that German car manufacturers and French winemakers would put pressure on their governments for the EU to strike a deal with the UK to protect the valuable UK export market.
According to the study author, Justin Protts, the figures showed how much both sides had to lose if they failed to reach a trade arrangement during the two-year process which would being with the triggering of article 50 next year.
He added, however, that the UK could have something of an easier time, both in terms of the lower overall total and its ability to alter its tariff schedule in a way that would help UK businesses.
''These figures highlight the importance of securing a post-Brexit trade deal not just for the UK but also for the EU,'' he said. ''European exporters have a great deal to lose without free trade across the continent,'' www.theguardian.com reported.