Overpaid by employer, advice please.

Megsmum

Hi all, last month I was overpaid by a small amount.  Somewhat foolishly I thought this was an extra payment (in line with other employees) for some extra work I'd  undertaken.  However, without a word or explanation they have deducted this from my salary this month.  I appreciate that they are entitled to do this but I would have paid tax and NI on this last month, how do I work out how much and am i entitled to a refund of the overpaid tax and ni, please ?

Undervalued

The tax and NI should correct itself because you have been paid correspondingly less this month.

Megsmum

I've paid tax and ni on my correct wage this month and then the extra has been taken off afterwards so I don't think an adjustment has been made in that regard. 

chrisbur

Megsmum said:

I've paid tax and ni on my correct wage this month and then the extra has been taken off afterwards so I don't think an adjustment has been made in that regard. 

If the deduction has been made from your net pay instead of your gross pay then this is definitely wrong. Your employer needs to correct this by deducting the amount owed from your gross pay next month and refunding to your net pay the amount they deducted from your net pay this month.
This will correct the tax position and in most cases the NI as well though if the correction does not fall in the same NI band as the error a manual adjustment will be needed.