What if something changes or I made a mistake after filing?

One amendment is included at no extra cost within 12 months of the original filing date. If something changes after we've filed — a P60 arrives with different figures, you realise you forgot to include some income, or HMRC queries something — just let us know via live chat and we'll sort it out. HMRC allows amendments to be made up to 12 months after the filing deadline for that tax year.