Tax Calendar UK for 2026: Don't Miss These Business Deadlines

The UK tax system dumps dates on you all year long. Miss one? Penalties. Interest charges. HMRC breathing down your neck. This Tax Calendar UK for 2026 covers what matters and when. VAT returns, corporation tax payments, PAYE deadlines — the stuff that keeps business owners awake at 3am. Get these right and you can actually plan your cash flow, keep your accountant from panicking, and stop that awful feeling when deadlines ambush you.

Knowing this timeline isn't just about staying compliant (though yeah, that's pretty crucial). It's about running your business without constantly fighting the tax system. When you see what's coming, you can work with your accountant early, sort paperwork before it becomes urgent, and turn these deadlines into planning tools instead of monthly crises.

Tax Calendar UK for 2026: Monthly Tax Obligations

Some tax stuff hits every month. Clockwork. Build it into your routine or spend your life scrambling.

Tax Calendar UK for 2026: PAYE and National Insurance

PAYE submissions happen on or before each payday through Real Time Information. Monthly payments? Due by the 22nd for electronic submissions. Still posting checks? You get until the 19th (seriously, upgrade your system).

January 2026 starts with P60 prep — every employee needs one by 31st May 2026. February through December follows normal patterns, but April gets messy because the new tax year kicks in on 6th April 2026. Your payroll system better handle that transition smoothly.

Tax Calendar UK for 2026: Construction Industry Scheme Returns

CIS returns hit by the 19th each month after the tax month ends. Construction companies need detailed records for every subcontractor payment and deduction. Summer 2026 will get crazy when construction activity picks up — more transactions, more headaches in your CIS calculations.

Tax Calendar UK for 2026: VAT Returns

VAT comes quarterly, timing depends on your assigned VAT period. Plan these wrong and your cash flow gets hammered.

Standard Quarterly Periods

Most businesses get standard quarters with returns due one month and seven days after quarter-end. For 2026, if your quarters end January, April, July, October:

January quarter returns? Submit by 7th March 2026. April quarters hit 7th June, right when you're juggling new tax year chaos. July quarter returns land 7th September. October quarters need completion by 7th December 2026.

These dates don't shift for weekends or holidays. Though HMRC occasionally shows mercy when deadlines hit non-working days.

Annual VAT Schemes Play by Different Rules

Annual Accounting Scheme users get two months after year-end for returns, but you're making interim payments all year. Flat Rate Scheme keeps quarterly submissions but simplifies calculations. Cash Accounting Scheme lets you report VAT when money actually moves instead of when invoices go out — still quarterly deadlines though.

Tax Calendar UK for 2026: Corporation Tax Throughout 2026

Corporation tax hits hardest annually, timing depends on your accounting period. Mess up this planning and your cash flow dies.

Corporation Tax Payment Schedule

Nine months and one day after your accounting period ends. Companies with March 2025 year-ends? Payment due 1st January 2026 — literally your first business obligation of the calendar year. Hope you saved cash from last year.

Large companies (profits over £1.5 million) deal with quarterly instalments in months 7, 10, 13, and 16 of their accounting period. That demands serious cash flow forecasting since you're prepaying tax on estimated profits.

Companies House Coordination

Confirmation statements need filing within 14 days of your incorporation anniversary or last confirmation statement. Every company has different 2026 dates based on incorporation timing.

Annual accounts? Nine months for private companies, six for public ones. Getting Companies House aligned with HMRC submissions prevents inconsistencies that attract unwanted scrutiny.

What Actually Matters

Monthly PAYE and CIS obligations hit by the 22nd each month for electronic submissions. VAT returns follow quarterly cycles with deadlines roughly five weeks after quarter-end.

Corporation tax payments come nine months after accounting period ends — plan cash flow accordingly. Large companies handle quarterly instalments requiring proper financial forecasting.

Annual filings have company-specific deadlines based on incorporation dates. Coordinate different tax obligations to avoid compliance gaps.

Common 2026 Tax Deadline Questions

What happens if I miss VAT deadlines?
Late VAT returns trigger automatic £200 penalties for up to one month late. One to six months? £400. After six months, you face £10 daily penalties. Repeat offenses put you on surcharge liability notices with percentage-based penalties on future late payments.

How do quarterly corporation tax instalments actually work?
Large companies pay 25% of estimated annual liability in months 7, 10, 13, and 16 of their accounting period. You can revise estimates if circumstances change, but underpayments mean interest charges on shortfalls.

Can I switch VAT return periods during 2026?
You can request changes through HMRC, though they need solid reasons like aligning with accounting periods or seasonal patterns. Give them two months' notice minimum — they might attach conditions preventing tax avoidance schemes.

What PAYE records must I maintain?
Employee details, pay rates, hours worked, tax codes, all deductions. Keep everything three years minimum after tax year ends. RTI submissions need accurate reporting for every payment, including benefits and expenses.

How does April 2026 tax year change affect compliance?
New rates and allowances start 6th April 2026. Update systems, verify employee tax codes are current, adjust automated calculations. Otherwise you'll have errors from day one of the new tax year.

Getting the Tax Calendar UK for 2026 right isn't just about avoiding penalties. It's about running your business without tax deadlines constantly lurking overhead. Plan properly and these dates become business rhythm instead of stress sources.

Companies treating tax calendar management as core business strategy — not just admin busywork — position themselves way better for 2026 growth and beyond.