Asos expects to benefit from the fall in the pound’s value after the UK voted to leave the EU because sterling’s slide has made its clothes cheaper for US and European customers.

The online fashion retailer said that because more than half of its sales come from outside the UK it is protected against a downturn in demand from British consumers.

The pound has fallen about 10% since the 23 June referendum. It has plunged to a series of 31-year lows against the dollar, with some economists expecting it to remain low as the economy slows.

In the short term, the pound’s fall has been good for some companies that sell goods and services abroad because it gives overseas customers more buying power. Asos covers most countries in the world and has expanded by launching websites targeted at the US, Germany and other markets.

Nick Beighton, Asos’s chief executive, said: “Our sales prices which are denominated off sterling now look cheaper to the US customer and look cheaper to the European customer. What we think that will give us is a greater sales trajectory.”

Beighton said it was too early to predict the long-term effects of Brexit but in the immediate term improved sales would more than make up for the higher cost of imported raw materials, such as cotton.

The gain from post-referendum currency swings is a marked contrast with two years ago when the strong pound and lack of flexibility in Asos’s pricing outside the UK forced it to slash prices and triggered profit warnings.

Beighton made his comments as Asos reported better than expected trading so far this financial year. Total retail sales rose 30% to £500.5m in the four months to 30 June. Asos’s first half finishes at the end of August.

UK sales rose 28% and international sales increased 31% as trading accelerated in the US, the EU and other overseas markets. Asos said it expected annual sales growth at the upper end of its previously stated range of 20-25%.