Vacation calculator: Calculate vacation days correctly
Vacation entitlement varies significantly between the UK and the US. In the UK, the Working Time Regulations 1998 guarantee every worker at least 5.6 weeks of paid leave. In the US, there is no federal mandate — entitlements depend entirely on employer policies. Part-time schedules, different working patterns and various special rules can make the calculation tricky.
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Vacation calculator: The key points at a glance
- Statutory minimum leave in the UK is 5.6 weeks per year under the Working Time Regulations 1998, which equals 28 days for a five-day week (bank holidays may be included). In the US, there is no federal minimum — entitlements depend on employer policy.
- When you join or leave mid-year, vacation is calculated pro rata: in the UK at about 2.33 days per full month worked for a standard entitlement; US policies typically follow a similar accrual model.
- Part-time workers receive the same proportional entitlement as full-time staff based on days worked per week, while maternity and parental leave continue to accrue leave in the UK in full.
- absentify calculates vacation entitlement automatically for every employee directly in Microsoft Teams and Outlook, including remaining leave and special cases.
How does the vacation calculator work out your entitlement?
The vacation calculator puts your statutory or contractual annual entitlement in relation to your actual working days per week. In the UK, 5.6 weeks for a five-day week means 28 days. If you work fewer days, the calculator scales the entitlement accordingly.
The basic formula is: Annual entitlement in working days = full-time annual entitlement × (your working days per week ÷ company full-time days per week).
| Working days per week | UK statutory minimum (5.6 weeks) |
|---|---|
| 5 days | 28 working days |
| 4 days | 22.4 working days |
| 3 days | 16.8 working days |
| 2 days | 11.2 working days |
Many employers grant more than the statutory minimum, typically 25 to 30 days plus bank holidays. In that case, the vacation calculator uses your contractual annual entitlement instead of the statutory baseline.
Which special cases must be considered when calculating vacation?
Vacation entitlement changes with part-time work, a mid-year start date, ending employment, sickness, maternity leave and parental leave.
What applies if you start mid-year?
If you join a company partway through the year, vacation is calculated pro rata. In the UK, entitlement accrues from day one at roughly 2.33 days per full month for a standard 28-day entitlement. During probation, your employer may restrict when you can take leave, but the entitlement still accrues.
Example with a start date: You start on 1 September with a 28-day annual entitlement. For the four months September to December, that is 28 × 4/12 = 9.33, typically rounded up according to your employer's policy.
How is vacation calculated when employment ends?
When employment ends, unused accrued leave is usually paid out. In the UK, your employer must pay out all accrued but unused statutory holiday. If you have taken more than you accrued, the employer may deduct the overpayment from your final pay. In the US, payout rules vary by state.
Days of remaining leave on termination are settled in the final paycheck where payout is required.
How many vacation days do part-time workers get?
Part-time workers have the same proportional vacation entitlement as full-time employees. What matters is the number of working days per week, not the hours per day.
Formula: Full-time annual entitlement × (your weekly working days ÷ full-time weekly days).
If you work three days per week and the company grants full-time staff 30 days, that equals 30 × 3/5 = 18 vacation days. The entitlement does not depend on earnings.
What applies for maternity and parental leave?
In the UK, vacation entitlement continues to accrue in full during maternity, paternity, adoption and shared parental leave. Unused days can be carried over. In the US, the FMLA provides 12 weeks of unpaid leave — whether vacation accrues during this time depends on your employer's policy.
Manage vacation in MS Outlook and Teams and calculate it automatically
A vacation calculator gives you certainty for individual cases. As soon as several employees, different working-time models and special cases come together, you need something that keeps calculating continuously. absentify takes over this calculation automatically and keeps remaining leave up to date at all times.
- Automatic calculation of vacation entitlement per employee, including part-time, pro-rata entitlements and special cases.
- A personal calendar for every employee with remaining leave at a glance, without manual spreadsheets.
- Full integration into Microsoft Teams and Outlook, without switching between platforms.
- Approval workflows and department overviews that make overlaps visible immediately.
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Vacation calculator – Frequently asked questions
For a mid-year start, pro-rata rules apply. Multiply your annual entitlement by the number of full months worked divided by twelve. In the UK, entitlement accrues from day one; after completing any contractual waiting period, the full annual entitlement applies for the following leave year.
With three working days per week, multiply the full-time annual entitlement by 3/5. If your employer grants full-time staff 30 days, you get 18 vacation days. Hours worked per day do not change the day count.
In the UK, accrued but unused statutory holiday must be paid out when you leave. If you have taken more than you accrued, your employer may deduct the difference from your final pay. US payout rules depend on state law and company policy.
Yes. Part-time workers have the same proportional statutory or contractual entitlement as other employees. The amount is based on weekly working days. During vacation, your usual pay continues according to your contract.
In the UK, entitlement continues to accrue in full during maternity and parental leave. Unused leave from before parental leave does not expire and can be taken afterwards. In the US, accrual during FMLA leave depends on employer policy.
absentify stores each employee's working-time model and annual entitlement and automatically calculates the vacation days due, including pro-rata entitlements when joining or leaving. Current remaining leave is always visible in the personal calendar, directly in Microsoft Teams and Outlook.