Tax residency evidence for life across borders

Day counts that stand up to scrutiny.

Book a call Try Daysium Free for 14 days

Your tax advice is sound. But between the advice and the investigation, records get lost.

Daysium closes that gap — automatically.

As tax authorities are
aggressively closing
'the tax gap,'

UK Compliance
interventions opened
by HMRC in 2022/23

Since 2018, 1.5 million UK
compliance interventions
have secured

For every £1 spent on
investigating HNWIs in
2023, HMRC recovered

Daysium is a tax residency evidence platform.

Know exactly where the line is with two powerful tax residency record-keeping tools.

Daysium Mobile automatically counts your days across every jurisdiction you spend time in. You build the evidence behind them — geo-tagged, securely logged, and ready if tax authorities ask questions.

Daysium Portal gives you and the people you trust a live, shared view of your status. They see your counts, not your evidence or your location.

Automated day counting.
Evidence that stands up.

There’s nothing to see here, everything is in order

Up-to-date day counts wherever you need them. Confident travel decisions. Know exactly where the line is, with evidence ready if questions arise.

Day Counts in the Palm of Your Hand

Automated Tax Law Compliance

Avoid unintentional overstays

Explore more Advising HNWIs?

Avoid unintentional overstays

Real-Time Compliance

Real-time insights into your day counts allow you to make confident, proactive travel decisions, avoiding unintentional overstays in any tax jurisdiction.

See how it works

Automation 1

Automated day counting

Eliminate human error

Real-time day counts across every jurisdiction. Confident travel decisions without the spreadsheet.

Reporting 2

Reporting

Robust record-keeping

Timestamped, geo-tagged records built continuously — so if questions arise, the evidence is already there.

Security 3

Security

Secure reporting in an encrypted app

Stored on Google Cloud Platform — infrastructure certified to ISO/IEC 27001:2022 standards. Daysium is also Cyber Essentials Certified.

Collaboration 4

Work with your advisor

Collaboration

Share reports through Daysium Mobile, or invite your advisor into Daysium Portal for a live, shared view of your status — no email attachments, no risk of interception.

Guided by
tax experts

Created in partnership with industry experts, Daysium tackles the complex challenges of day counting and record-keeping for tax residency. Our partner community plays an active role in realising this vision, bringing deep expertise in tax compliance for the globally mobile.

Runner-up for UHNW Private Client Services of the Year — Citywealth Magic Circle Awards 2026.

Finalist in the UHNW Private ClientServices of the Year award 2026

Founding Partners

Exciting technology

"The technology that Daysium has developed is incredibly exciting and I’ve really been enjoying getting under the hood of what’s in store for individuals that utilise the software! The team's passion and vision for solving the ongoing nightmare of tracking for residency status is brilliantly evident."

Rhys Thomas,
Managing Director,
WTT Group

Valuable Partnerships

"A pioneering company in the field of day counting and record-keeping. Their innovative tool simplifies complex date-related calculations, offering immense value to our clients. This partnership marks a significant step towards enhancing our client services with advanced solutions."

Alan Kennedy,
Managing Director,
Trident Tax

Simplifying international tax

"The Daysium team deliver technology that makes taxes easier for expats and globally mobile individuals. What's not to like about that? We're really excited to work with them and offer our clients the ability to use this technology."

Stephanie Wickham,
Founder,
Expat Taxes

Protect yourself in a tax dispute

"Users of Daysium will be unlikely to see any additional tax liabilities if the platform has been used correctly.

Should any additional tax liabilities arise though, I would certainly be confident to put forward arguments that the use of the software was itself a means of taking reasonable care to pay the correct amount of tax."

Sarah Scala,
Director NHD Tax
Solutions & Founder of
The Contentious Tax Group