Personal Savings Allowance and self assessment calculation

I have a very simple tax return, and have almost finished it. I have a little bank interest which is well below the Personal Savings Allowance, but the "view your calculation" shows I have to pay tax on this small amount of interest by virtue of it being added to my income and taking me a little over what PAYE has already taken. So - is bank interest tax free or not? All the blurb says I can have it tax free up to my PSA, yet the SA calculation says no.

Hi SurreyFox,
This is still taxable income so shows as such on the calculation.
However, if the amount is below the personal savings allowance, you will see that the tax rate is 0%
This is shown further down on the full calculation on how your tax is calculated.
Thank you.