A tax residence platform for life across borders.
Daysium records your time across borders, applies the rules set for your position, and builds the evidence behind it.
Tax residence is decided by facts. Those facts are created through the year.
A day count is only as strong as the record behind it.
The information environment around international tax compliance has changed.
There’s nothing to see here — everything is in order.
Daysium applies the rules set for your position, keeps your counts current, and builds a record designed to stand up to scrutiny.
See how it works
Guided by
tax experts
Shaped with the people who use it, Daysium has been developed with tax advisors, accountants, tax lawyers, former HMRC inspectors, fiduciary professionals, family offices and internationally mobile clients.
Our Founding Partners bring experience in residence, compliance and disputes, helping shape the rules, evidence and workflows behind the platform.
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
Fantastic product
We found out about Daysium from our advisors, it’s a fantastic product, very easy to use and with someone on the end of the phone in case of need or to fix any issues, we would and have recommended it to anyone that would need such a product, it’s totally intuitive too!
Nick T,Monaco No more spreadsheets
After more than two decades of manually counting days spent in various jurisdictions using Excel, I discovered Daysium. It’s transformed how I record my whereabouts — automated, precise, a defensible record ready for when I need it.
Sanjeev P,Zurich 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
Founding Partners
Recognised by
Finalist two years running at theDigital Jersey TechAwards2024 – Startup Category2025 – Fintech, Startup
#2 Most Recommended StartupOut of 3,000+ companies, Daysium was ranked 2ndin a live, AI-powered scoring of Europe’s topstartups by global VCs & investors