Methodology: Full-Time Equivalent (FTE) Calculator

What this calculator gives you

This tool estimates full-time equivalent (FTE) headcount the way federal Affordable Care Act (ACA) employer-size rules sketch workforce size for Applicable Large Employer (ALE) questions: count full-time employees, convert non-full-time hours into equivalents, and average across months.

It is a planning estimate for small-business operators who need a transparent number. It is not tax advice, not a legal determination of ALE status, and not a substitute for HealthCare.gov’s FTE calculator or IRS guidance.

The basic method

For each calendar month:

full-time employees =
  people averaging ≥ 30 hours of service per week
  (or ≥ 130 hours of service in that month)

non-full-time FTE =
  (sum of hours of service of non-full-time employees,
   with each person capped at 120 hours) ÷ 120

monthly total = full-time employees + non-full-time FTE

For a year (or any set of months you enter):

average monthly FTE = mean of monthly totals

floored workforce size = floor(average monthly FTE)

IRS examples round a fractional annual average down to the next lowest whole number before comparing to 50.

Worked examples

Example A — IRS Company X (not ALE)

Same shape as the IRS “Company X” illustration: 55 people on payroll can still be under 50 for ALE counting after part-time hours are converted.

Example B — IRS Company Y (ALE candidate)

Example C — Weekly roster path

Three employees: 40 hrs/week, 40 hrs/week, 20 hrs/week.

• Two people count as full-time (weekly hours ≥ 30).
• One person at 20 hrs/week → monthly hours ≈ 20 × (52/12) ≈ 86.67 → FTE ≈ 86.67 ÷ 120 ≈ 0.72.
• Monthly total ≈ 2.72.

The weekly path uses 52/12 so that 30 hours/week maps exactly to 130 hours/month, matching the federal monthly full-time test.

Full-time vs full-time equivalent

Full-time (for this monthly count) is a person who averages at least 30 hours of service per week during the month, or who has at least 130 hours of service in the month.

Full-time equivalent is not a person—it is a fraction built from people who are not full-time for that month. Their hours are added (capped at 120 per person), then divided by 120.

An employer can have dozens of part-time people and still land under 50 FTE if hours are low—or cross 50 with relatively few full-time staff if part-time hours are high.

The 50-employee ALE threshold

Under federal rules summarized by the IRS ALE page, if an employer has at least 50 full-time employees including full-time equivalents, on average during the prior calendar year, the employer is generally an Applicable Large Employer for the current calendar year (employer shared responsibility and ALE reporting).

This calculator flags when the floored average of the months you entered is ≥ 50. That flag is a sketch, not a determination.

What is modeled

• Full-time headcount at the 30 hrs/week / 130 hrs/month concept.
• Non-full-time hours ÷ 120 (aggregate totals or weekly roster).
• Per-person 120-hour cap on the roster path.
• Average across 1–12 months on the aggregate path.
• Floor of the average for an ALE-style whole-number size.
• Threshold flag at 50 with estimate-only language.

What is not modeled

• Seasonal-worker exception (workforce over 50 for 120 days or fewer when excess are seasonal workers).
• Controlled-group / common-ownership aggregation under IRC §414.
• TRICARE / Veterans’ coverage exclusion from the 50-employee count for certain months.
• Look-back measurement periods, stability periods, and variable-hour employee classification for offer of coverage (separate from ALE size math).
• Whether an ALE must offer coverage to part-time employees (generally the shared-responsibility offer rules focus on full-time employees—not the same as the FTE counting used for ALE status).
• State insurance or leave definitions of FTE (this tool is federal ACA employer-size style only).
• PPP loan FTE formulas or other non-ACA “FTE” definitions.

When this gets re-reviewed

Recheck if Congress or Treasury changes the 30-hour, 130-hour, 120-hour, or 50-employee parameters, or if IRS revises the published ALE determination examples. Threshold constants here are long-stable statutory concepts; still re-verify against IRS and HealthCare.gov annually when the tool is fact-checked.

Data sources

• IRS — Determining if an employer is an applicable large employer — full-time definition, FTE ÷ 120 method, 50-employee threshold, worked examples, seasonal and aggregation notes.
• 26 U.S.C. §4980H — employer shared responsibility / ALE framework.
• HealthCare.gov — Full-time Equivalent (FTE) Employee Calculator — official calculator surface for FTE concepts.
• Companion budgeting: Employee Payroll Cost Calculator for fully loaded cost once headcount is known.
• Optional ops context: Employee time tracking app for small business.

How accurate is this?

For a single month with known full-time headcount and accurately capped non-full-time hours, the monthly total matches the IRS arithmetic in the published examples. Multi-month averages match the “sum months ÷ 12” idea when you enter twelve months; entering fewer months produces a partial-year sketch, not a full prior-year ALE calculation.

Aggregate mode cannot apply the per-person 120-hour cap unless you already capped each person’s hours before summing. Use the roster path when anyone works more than 120 non-full-time hours in a month.

Use this tool to understand the shape of ACA FTE math. Use IRS publications, HealthCare.gov, and qualified advisors for filings and ALE decisions.