How much is US to UK import tax?

Items under a declared value of £18 are VAT-free when they arrive in the UK by mail.

Items valued at £18 and over on the customs declaration are charged at the standard 17.5% VAT rate which is collected by Royal Mail. There is also a £4 handling charge for this.

Items sent from within the EU are always tax free (except dutiable goods such as tobacco and alcohol).