Vacation Days Calculator

A vacation days calculator helps employees, employers and contractors estimate annual leave entitlement, leave accrued to a selected date, remaining balance and the number of leave days needed for a planned absence. It is especially useful when someone joins or leaves during a leave year, works part-time, has irregular hours, carries leave forward or needs to exclude public holidays from a booking.

What the Vacation Days Calculator can calculate

The calculator has two separate modes. Entitlement and balance estimates the employee’s full-year allowance, prorated allowance, leave accrued to a chosen date, current availability and projected year-end balance. Leave request counts how many working days or hours a particular holiday period will use.

The tool can account for:

• annual entitlement entered in days, weeks or hours;
• full-time and part-time working patterns;
• joining or leaving part way through the leave year;
• calendar-day, monthly or hours-based accrual;
• carried-over leave;
• leave already taken and leave already booked;
• public holidays included within the allowance;
• rounding to half days or whole days;
• custom working weekdays;
• public holidays or excluded dates;
• half-day leave at the start or end of a booking;
• the employee’s next working day after leave.

Every preset is editable because contractual leave may exceed the statutory minimum.

How annual leave entitlement is expressed

Annual leave may be written as a number of days, weeks or hours. Converting everything into working days makes comparisons easier.

The basic conversions are:

• Days: use the stated number directly.
• Weeks: annual leave days = leave weeks × working days per week.
• Hours: annual leave days = leave hours ÷ hours per working day.

A worker who receives 5.6 weeks and works five days a week has 28 days of leave. A worker who receives 5.6 weeks and works three days a week has 16.8 days. The weekly entitlement stays equivalent, while the number of leave days changes with the work pattern.

UK statutory holiday entitlement

Most UK workers are entitled to 5.6 weeks of paid statutory holiday each leave year. For a regular five-day worker, this normally equals 28 days. Statutory entitlement is capped at 28 days even when a worker regularly works six days each week, although an employer can provide more contractual leave.

Bank holidays do not automatically have to be additional to the statutory allowance. An employer can include them within the 5.6 weeks if the contract and holiday policy are structured that way. This is why the calculator includes a setting for public holidays included in entitlement.

For a five-day employee receiving 28 days including eight bank holidays, the number of freely bookable days may be 20 after the eight allocated public holidays are deducted. If the employer grants 28 days plus bank holidays, the public-holiday deduction should remain at zero.

Prorating leave for someone who joins during the year

When employment starts after the leave year has begun, the annual entitlement is normally reduced for the part of the leave year in which the employee is employed. The calculator can prorate by calendar days or by months.

The calendar-day formula is:

Prorated entitlement = full-year entitlement × employed days in the leave year ÷ total days in the leave year.

Suppose the leave year runs from 1 January to 31 December, the full allowance is 28 days and employment begins on 1 July. The employee is present for roughly half the leave year, so the estimate is approximately 14 days.

A monthly method instead allocates part of the allowance for each month or part-month according to the selected policy. This can differ slightly from daily prorating, especially when someone begins near the start or end of a month. Use the method applied by the employer rather than choosing whichever result is more favourable.

Prorating leave when employment ends

The same principle applies when a worker leaves before the end of the holiday year. Enter the employment end date and the calculator limits the entitlement to the employment overlap.

Compare the result with leave already taken. Final-pay adjustments and payment for unused leave depend on the contract and applicable law.

Accrued leave versus full-year entitlement

Full-year entitlement is the total allowance for the whole relevant employment period. Accrued leave is the portion built up by a selected date. These values are not always the same.

For example, an employee may have a projected 28-day annual entitlement but have accrued only 14 days halfway through the year. If they have taken 10 days and booked 5 more, their current accrued availability may be negative even though the year-end balance is still positive.

The calculator shows both:

• Available now: accrued leave plus carryover, less leave taken, booked leave and any public-holiday allocation.
• Projected year-end balance: total prorated entitlement plus carryover, less leave taken, booked leave and allocated public holidays.

Irregular-hours and part-year workers

For leave years beginning on or after 1 April 2024, official UK guidance uses a 12.07% accrual method for qualifying irregular-hours and part-year workers. Leave is calculated from hours worked in each pay period. The 12.07% figure is derived from 5.6 weeks of statutory leave compared with 46.4 working weeks.

The basic formula is:

Holiday hours accrued = hours worked × 12.07%.

If a worker completes 30 hours in a pay period, the unrounded result is 3.621 holiday hours. Official guidance applies specific rounding to the nearest hour for this statutory method. The calculator includes an hours-percentage mode so the user can enter worked hours and the relevant accrual percentage.

A contract providing more than 5.6 weeks requires a different percentage. The percentage should be calculated from the total contractual holiday and remaining working weeks, rather than applying 12.07% automatically.

Carryover, sickness and family-related leave

Carryover depends on the contract and the reason leave was not taken. GOV.UK guidance says ordinary carryover for a worker with 28 days is usually limited to eight days, while different protections can apply when leave was prevented by sickness or family-related leave. Enter only a balance confirmed by HR because deadlines and protected leave can differ.

How the leave-request mode counts days

A date range contains calendar days, but only selected working days normally consume leave. The calculator checks every date between the start and end date, keeps the selected weekdays and removes listed public holidays.

For a standard Monday-to-Friday schedule, a holiday from Monday to Sunday usually uses five leave days. If Wednesday is an excluded public holiday, the request uses four days. The calculator also identifies the next selected working day after the absence.

Half-day settings can reduce the first or last chargeable day. If only one working day is in the period and both ends are marked as half days, the calculator uses the smaller single-day fraction rather than double-counting the same date.

Public holidays and bank holidays

Public holidays can be included in the annual allowance or excluded from a specific booking. In entitlement mode, enter an allocation only when those days reduce the annual balance. In request mode, exclude only dates that should not consume leave under the employee’s schedule and contract.

Rounding leave fairly

Prorated results often contain fractions. Use the employer’s documented method: no rounding, nearest half day, rounding up to a half day or rounding up to a whole day. Apply rounding after the main calculation rather than repeatedly during intermediate steps.

Common mistakes

• Using calendar days instead of working days: weekends should not consume leave unless they are normal working days.
• Ignoring the leave-year dates: the employment year and holiday year may not be identical.
• Using 28 days for every part-time worker: weeks should normally be converted using the actual work pattern.
• Deducting bank holidays twice: do not subtract them from entitlement and again from the balance unless policy requires both entries.
• Confusing accrued and projected leave: future entitlement may not be available immediately.
• Applying 12.07% to everyone: it is a specific method for qualifying irregular-hours and part-year workers.
• Ignoring booked leave: approved future leave reduces the amount available for new bookings.
• Treating the calculator as approval: an entitlement estimate does not confirm that specific dates are authorised.

Using the calculator reliably

Use the entitlement, leave-year dates and work pattern shown in the contract or HR system. Confirm whether public holidays are additional or included, and enter carryover, leave taken and approved bookings separately. Save the inputs so any difference can be traced to rounding, accrual method, public holidays, joining date or contractual enhancement.

Frequently asked questions

Official sources

• GOV.UK: Calculate leave entitlement
• GOV.UK: Holiday entitlement calculator
• GOV.UK: Holiday entitlement reforms and 12.07% accrual
• GOV.UK: Holiday pay

Last reviewed: 20 June 2026.