Annual Leave Calculator: Pro Rata Accrual & Balance

This calculator is a leave-year balance tracker. It starts with the annual entitlement, anchors it to the employer's leave-year start, and separates leave already taken from leave booked for later. That distinction answers two different questions: how much leave has been earned by today, and how much remains for the whole year after approved bookings.

It can track a statutory 28-day allowance or a larger contractual allowance. It does not decide whether a request should be approved, calculate holiday pay, or replace the employer's HR record. Check that all inputs use the same unit, normally days.

The calculator measures calendar days from the first day of the selected leave-year start month, converts that span to elapsed months, and applies the proportion to the annual entitlement. A 28-day entitlement halfway through the leave year is about 14 days accrued, subject to rounding.

This makes the result responsive to today's date rather than assuming a fixed manual month count, but it remains an estimate. Employer systems may use exact days, completed months or payroll periods under the contract. Accrual cannot exceed the entered annual entitlement. If the result looks wrong, check the selected start month and calculation date.

Taken leave is time used on or before the calculation date. Booked leave is approved time later in the leave year. The full-year projected balance is entitlement minus both amounts. The accrued-to-date balance compares leave earned so far with leave taken so far; future bookings are shown separately so they do not make today's accrual look lower than it is.

If more leave has been taken than accrued, the displayed accrued balance stops at zero; the employer may still permit leave in advance. If taken and booked leave exceed the annual entitlement, the projected balance also stops at zero. Compare the input totals as well as the balance so an overbooking is not hidden by that floor.

Statutory annual leave continues to accrue during sickness absence and statutory family leave, including maternity leave. A worker who is off sick may therefore have more leave available when they return, even though no holiday was taken during the absence. Keep sickness absence separate from the days already taken input unless the worker actually used annual leave.

If sickness prevented statutory leave being taken, carry-over may be required. The employer should record the carried days separately, check the applicable policy and avoid silently folding them into a new annual entitlement. Use the [SSP calculator](/ssp-calculator/) for statutory sick pay and this page for the leave balance.

Almost all UK workers are entitled to 5.6 weeks of paid annual leave under the Working Time Regulations 1998. For someone working five days a week, that is 28 days. The statutory day-based entitlement is normally days worked each week × 5.6, capped at 28 days.

Employers can provide more than the statutory minimum. Enter the full contractual amount if you want the tracker to include those extra days. Contractual rules can differ for carrying over or selling the extra portion, but they cannot reduce statutory rights. Irregular-hours and part-year workers use the separate 12.07% accrual rules for qualifying leave years.

There is no automatic right to paid time off on a bank holiday. An employer can include bank holidays within the statutory 5.6 weeks or provide them on top, and the employment contract should say which. Before entering 28 days, confirm whether that number already includes the relevant bank holidays.

Regional calendars differ across England and Wales, Scotland, and Northern Ireland, and a business can require work on a bank holiday with leave at another time. The tracker does not add regional bank holidays silently. Enter the contractual annual total so the balance does not double-count days that are already included.

A worker employed for only part of a leave year receives a pro-rata entitlement. For a new starter, use the employment start date and the employer's agreed part-year entitlement rather than assuming the full annual amount is immediately available. At termination, accrued statutory leave not taken is normally paid, while overtaken leave can be deducted only where the contract permits it.

If working days or hours change during the year, split the calculation into periods at each pattern. Converting the balance to hours is often fairer when daily lengths vary. Do not overwrite earlier accrual with the new schedule for the whole year.

Annual leave continues to accrue during sickness absence and statutory family leave, including maternity leave. GOV.UK rules allow statutory leave to be carried over in specified circumstances, such as when sickness or family leave prevented it being taken, or when the employer did not give a reasonable opportunity to take it. Contractual extra leave can have different carry-over terms.

Do not add carried leave to the annual entitlement unless the organisation records it that way. Keep it as a separate adjustment where possible, with an expiry date. Holiday taken during sickness, cancelled bookings and leave restored after illness should also be reconciled before trusting the balance.

GOV.UK and Acas guidance says employers must not round statutory entitlement down in a way that removes leave. During the first year, statutory monthly accrual rules can require a fraction to be rounded up to the nearest half day, while many systems retain hours or decimals to avoid repeated rounding errors.

Common mistakes include using the calendar year instead of the contractual leave year, counting bank holidays twice, mixing hours and days, treating a pending request as booked, and subtracting the same cancelled leave twice. Reconcile the calculator with approved requests and payroll records before confirming a balance or termination payment.

Start with the full annual entitlement, set the correct leave-year start, and enter 5 days taken and 3 days booked or replace those defaults with the worker's record. The calculator uses dates to estimate accrual as of today and separately shows the projected full-year balance.

Check bank-holiday treatment, part-year service, changed working patterns, carry-over and contractual rounding before acting on the result. For irregular-hours or part-year workers covered by the post-April 2024 rules, use a 12.07% hours-based holiday entitlement calculation rather than treating this day tracker as the accrual method.