Self Assessment deadline
Dec 1, 2026 – Jan 31, 2027
Why demand moves
UK Self Assessment returns are due 31 January: bookkeepers and accountants peak in December and January.
What peaks
BYZXPO has no listings in this country yet — these are the kinds of business that do well this season.
Plan for this season
See where there's room for you
Compare how many businesses of each busy type are near a place with the country as a whole: gaps, typical or crowded. Free accounts get one check a month; paid plans get more.
Sign in to use itBusiness ideas for this season
Mobile tax filing help
Low start-up costReceipts-to-books service for small shops
Low start-up costKey dates
Start getting ready
Oct 20 · 6 weeks before
Starts
Dec 1 · In 43 days
Ends
Jan 31
Get ready checklist
Open appointments early
Send document checklists to clients
Plan extra hours for the last two weeks
Also in
The same season in other markets — useful for importing and exporting.
Questions about Self Assessment deadline in the United Kingdom
When is Self Assessment deadline 2026 in the United Kingdom?
Self Assessment deadline 2026 in the United Kingdom runs from December 1, 2026 to January 31, 2027.
Which businesses are busiest during Self Assessment deadline?
accountants, tax preparation, bookkeeping services and financial advisors see the most demand. UK Self Assessment returns are due 31 January: bookkeepers and accountants peak in December and January.
When should businesses start preparing for Self Assessment deadline?
About 6 weeks before — from October 20, 2026 for Self Assessment deadline 2026. Open appointments early
What business can I start for Self Assessment deadline?
Ideas for Self Assessment deadline: mobile tax filing help (low start-up cost) and receipts-to-books service for small shops (low start-up cost).