Tax underpayment from previous years in tax code

misterdoubleyoo

Hi

I've had zero sensible response from HMRC so i thought i'd try here.

My current tax code states that i have underpaid tax in 2018/19 and that the missing tax is being recovered via my Tax Code. Why then, when i completed my Self Assessment for 18/19 did i receive a refund due to overpaid tax??

How can i have both an underpayment and also a refund for overpayment for the same tax year?

Currently receiving take home pay almost 20% lower than i think it should be and it's hurting!! Also - my tax code is ending in M1 which is emergency tax if i'm right. HMRC seem to think this is correct though?!?

Any guidance much appreciated!

On-the-coast

Probably something has come to light in current tax year that impacts previous year(s) calculations. Yes this can and does lead to the scenario you outline.
I guess most common is child benefit clawback (for taxable earnings over 50k), but many other possibilities - including error on original calculations.