You must register for UK VAT once your taxable turnover passes £90,000, but Amazon and eBay already collect and remit VAT on your behalf for some sales under marketplace facilitator rules — which doesn't exempt you from registering, it just changes what you're responsible for reporting.
Shopify, by contrast, doesn't do this for you, since it's your own storefront rather than a marketplace, so VAT on those sales is entirely down to you to charge, collect and report correctly. Selling across both at once is where it gets genuinely complicated: you need a single, reconciled view of turnover across every channel to know if you've crossed the threshold, and separate treatment of Amazon's facilitator-collected VAT versus your own Shopify VAT so you don't double-count or miss it. If you're selling across more than one platform and aren't confident your VAT position is correct, that's worth checking now rather than at your next VAT return.
We reconcile VAT across Amazon, Shopify, Etsy and eBay for Brighton sellers, so nothing gets double-counted or missed.
Talk to an AccountantYou must register for UK VAT once your taxable turnover passes £90,000, but Amazon and eBay already collect and remit VAT on your behalf for some sales under marketplace facilitator rules — which doesn't exempt you from registering, it just changes what you're responsible for reporting.