FTE Calculation: How to Work Out Full-Time Equivalent

Full-time equivalent (FTE) is a unit that expresses a workforce as the number of full-time employees it would take to do the same work. One person working a full-time week is 1.0 FTE. Two people each working half a full-time week are also 1.0 FTE between them.

FTE exists because headcount lies. Twelve people on your payroll might represent nine and a half full-time workers, and the gap between those two numbers is where budgets, grant reports, compliance thresholds and pro-rated leave entitlements all go wrong. This guide covers both FTE calculation methods, with every step of the arithmetic shown.

Key Takeaways

• Headcount method: add up each person’s assigned FTE value (1.0, 0.5, 0.6).
• Hours method: total hours worked ÷ full-time hours for the same period.
• “Full-time” is not universal. It is 38 hours a week under the Australian National Employment Standards and 30 hours a week for US ACA purposes.
• Use annual hours for grant reporting, monthly hours for ACA thresholds, and weekly hours for rostering and leave pro-rating.

What Does FTE Actually Measure?

FTE measures capacity, not people. It converts a mixed workforce of full-time, part-time and casual staff into a single comparable number of full-time-equivalent workers.

That distinction matters most in three places. Budget holders use FTE to cost a team, because two 0.5 FTE staff cost roughly what one 1.0 FTE costs. Funders and regulators use FTE to size an organisation fairly, so a company cannot dodge a threshold by splitting roles. HR uses FTE to pro-rate entitlements, so a part-time employee gets a proportionate share rather than an arbitrary one.

One warning before the formulas: FTE is a capacity measure, not a headcount substitute. You still report headcount for anything person-based, such as who is entitled to a benefit or who needs a laptop.

How Do You Calculate FTE Using the Headcount Method?

The headcount method assigns each employee an FTE value based on their contracted fraction of a full-time role, then adds them up.

FTE = Sum of each employee’s contracted fraction of full-time

A design agency has:

• 4 full-time employees at 1.0 FTE each = 4.0
• 3 employees at four days a week (4 ÷ 5 = 0.8) = 2.4
• 2 employees at three days a week (3 ÷ 5 = 0.6) = 1.2
• 1 employee at two days a week (2 ÷ 5 = 0.4) = 0.4

Total: 4.0 + 2.4 + 1.2 + 0.4 = 8.0 FTE from a headcount of 10.

This method is fast, easy to explain, and accurate when contracts are stable. It falls apart with variable hours, overtime, or casual staff, because a contracted fraction stops describing reality.

How Do You Calculate FTE Using the Hours Method?

The hours method divides actual hours worked by the full-time hours for the same period. It is the more defensible method and the one most external reporting requires.

FTE = Total hours worked ÷ Full-time hours for the same period

Weekly Hours Method

Use a full-time week as your divisor. In Australia, the maximum ordinary hours for a full-time employee is 38 per week under the National Employment Standards, so we will use 38.

A café roster covers:

• 6 staff × 38 hours = 228 hours
• 4 staff × 19 hours = 76 hours
• 2 staff × 30 hours = 60 hours

Total hours = 228 + 76 + 60 = 364 hours

364 ÷ 38 = 9.58 FTE

Twelve people on the roster, 9.58 FTE of capacity. That 2.42 gap is what a headcount-based staffing plan would have silently over-counted.

Annual Hours Method

Use total annual hours instead, which smooths out seasonal and variable schedules. In a 40-hour-week country, full-time annual hours are 40 × 52 = 2,080. On a UK 37.5-hour week it is 37.5 × 52 = 1,950.

A research assistant works 1,560 hours in a year against a 2,080-hour full-time year:

1,560 ÷ 2,080 = 0.75 FTE

This is the method grant funders and research bodies normally ask for, because it lets them convert a person’s time on a project into a cost without caring how the weeks were arranged.

Monthly Hours Method (ACA Thresholds)

US employers determining Applicable Large Employer (ALE) status use a monthly variant. The IRS treats an employee as full-time at 30 hours a week or 130 hours a month, and converts everyone else into FTEs by dividing their combined monthly hours (capped at 120 hours each) by 120. An employer averaging 50 or more full-time employees plus FTEs across the prior calendar year is an ALE.

Worked through for one month:

• 40 full-time employees (30+ hours a week) = 40
• 20 part-time employees × 90 hours = 1,800 hours
• 1,800 ÷ 120 = 15 FTEs
• 40 + 15 = 55

Fifty-five is above the 50 threshold for that month. ALE status is based on the average across all 12 months of the prior year, not a single month, so run the calculation monthly and then average.

Which FTE Method Should You Use?

Method	Formula	Best for	Watch out for
Headcount	Sum of contracted fractions	Quick internal planning, stable contracts	Ignores overtime and variable hours
Weekly hours	Weekly hours ÷ full-time week	Rostering, capacity planning, leave pro-rating	“Full-time” differs by country and award
Annual hours	Annual hours ÷ full-time year (e.g. 2,080)	Grant reporting, project costing, budgets	Choose 2,080 or 1,950 and stay consistent
Monthly hours	Monthly hours ÷ 120, plus full-time count	US ACA / ALE determination	120-hour cap per employee; average over 12 months

If in doubt, use hours. It survives an audit; a contracted fraction often does not.

How Do You Use FTE to Pro-Rate Leave?

Multiply the full-time entitlement by the employee’s FTE value. Both routes give the same answer when your inputs are consistent.

In the UK, statutory holiday entitlement is 5.6 weeks, which is 28 days for someone working five days a week. For an employee working three days a week:

• Weeks route: 5.6 weeks × 3 days = 16.8 days
• FTE route: 3 ÷ 5 = 0.6 FTE, then 0.6 × 28 days = 16.8 days

Identical, as they should be. Express part-time entitlement in days of their working week rather than hours where you can, because 16.8 of their days is far easier for the employee to check than a converted hours figure.

This is not optional generosity. UK part-time workers must not be treated less favourably than comparable full-time colleagues, and benefits are applied pro rata. The same pro-rating logic drives accrual balances, which we break down in our leave accrual calculation guide and our walkthrough of part-time holiday entitlement.

FTE also fixes your absence reporting. A headcount-based denominator over-states available time when part-timers are in the mix, so use FTE-weighted days instead, as covered in our guide to the absence rate formula.

Frequently Asked Questions

What is 0.5 FTE in hours?

It depends on your full-time week. On a 40-hour week, 0.5 FTE is 20 hours. On a 38-hour Australian full-time week it is 19 hours, and on a 37.5-hour UK week it is 18.75 hours. Always state the full-time baseline alongside any FTE figure, or the number is unreadable.

Do casual and temporary staff count towards FTE?

Yes, when you use the hours method. Add their actual hours worked into the total and divide by the full-time hours for the period. The headcount method cannot handle them, because casual staff have no contracted fraction. This is the single biggest reason to prefer hours.

How many decimal places should FTE use?

Two decimal places is the working standard for internal reporting and pro-rating, for example 9.58 FTE. Compliance calculations may specify their own rounding: the IRS ALE calculation, for instance, rounds the FTE figure down to the nearest whole number. Follow the rule of whichever body is asking.

Is FTE the same as headcount?

No. Headcount counts people; FTE counts full-time-equivalent capacity. A company with 12 part-time staff each working half a week has a headcount of 12 and an FTE of 6.0. Report both. Use headcount for anything person-based and FTE for anything capacity-based.

Keeping FTE and Leave in Sync

FTE only stays accurate if contracted hours, working patterns and leave entitlements live in the same place. When someone drops from five days to three, their FTE, their holiday entitlement and their accrual rate all need to change on the same date, and spreadsheets rarely do all three.

Leave Balance holds each employee’s working pattern and pro-rates their entitlement automatically when it changes. Flat $10/month, unlimited employees, 14-day free trial.