When you make a purchase, Bitstack rounds up your expense to the nearest euro and invests the spare change in Bitcoin. For example, a coffee bought for €2.60 is rounded up to €3.00 and the €0.40 difference is invested in Bitcoin.

Bitstack calculates the sum of all your roundups throughout the week and debits your payment method at the end of the week for the total of roundups of that week. You can view your roundups directly in the app under Roundups and the details of your transfers by tapping on the Activity tab.