HMRC Tax Deadlines 2026/27: Every Date You Need to Know

HMRC & Compliance · 8 min read · Updated 2026-03-20

A complete calendar of HMRC tax deadlines for 2026/27, covering self assessment, corporation tax, VAT, PAYE, and penalty structures.

Written by Krishna, Founder & HMRC-registered tax agent at TaxRoot.

What happens if I miss a self assessment deadline?

If you file your self assessment return even one day late, HMRC charges an automatic £100 penalty, regardless of whether you owe any tax. After 3 months, daily penalties of £10 per day are charged for up to 90 days (maximum £900). After 6 months, a further penalty of 5%…

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