1Tap Receipts calculates your effective tax rate. This means that the tax rate we display to you is the average percentage of tax you will pay on your whole income. This is calculated in relation to your National Insurance contributions and the tax bracket your income places you in.
You can adjust your tax rate in your 1Tap Receipts app by going so "Settings" and clicking on "Income tax". From there you can set your tax rate - you do that by adjusting your annual profit with the slider at the bottom.
For a more in-depth look at how your tax is calculated check out www.uktaxcalculators.co.uk