The staffing level question — how many people do I actually need? — is the most common workforce planning problem for small businesses. Hire too few and you are understaffed during peak hours, burning out your team and losing customers. Hire too many and your labour costs eat your margins. The answer depends on your demand pattern, the roles you need to fill, and the compliance rules that limit how many hours each person can work.
This article gives you a practical framework for calculating staffing levels, with specific examples for cafés, retail, healthcare, and office-based teams.
Key Takeaways
- Staffing levels are determined by demand (how many customers or tasks you need to handle), capacity (how many hours your team can work), and compliance (legal limits on hours and rest).
- The basic formula is: staffing level = peak demand hours ÷ (hours per employee × availability factor).
- The availability factor accounts for leave, sickness, training, and turnover — typically 0.75–0.85 for most businesses.
- Under-staffing costs more than over-staffing: lost revenue, overtime costs, and employee turnover.
- Review staffing levels quarterly, not annually — demand changes faster than annual reviews can keep up.
The Staffing Level Formula
The simplest way to calculate how many staff you need:
Number of employees = Peak demand ÷ (Hours per employee × Availability factor)
Let’s break this down:
Step 1: Measure Peak Demand
Peak demand is the maximum number of staff needed at any point during your busiest period. Measure this by:
- Customer count: How many customers do you serve per hour at peak?
- Task count: How many tasks need to be completed per hour at peak?
- Service ratio: What is the minimum staff-to-customer or staff-to-task ratio?
| Business Type | Peak Demand Metric | Typical Peak Ratio |
|---|---|---|
| Café | Customers per hour | 1 staff per 15–20 customers/hr |
| Retail | Customers per hour | 1 staff per 20–30 customers/hr |
| Care home | Residents | 1 carer per 4–6 residents |
| Office | Employees supported | 1 admin per 15–25 employees |
Step 2: Determine Hours Per Employee
This is not 40 hours per week — it is the actual available hours after accounting for the work pattern:
| Factor | Calculation |
|---|---|
| Standard work week | 38–40 hours |
| Minus annual leave | ~4 weeks = ~152 hours/year = ~3 hours/week |
| Minus public holidays | ~10 days = ~80 hours/year = ~1.5 hours/week |
| Minus sick leave | ~5 days = ~40 hours/week ÷ 52 × 5 = ~3.8 hours/week |
| Minus training | ~2 days = ~16 hours/year = ~0.3 hours/week |
| Available hours per week | ~31–34 hours/week |
Step 3: Apply the Availability Factor
The availability factor accounts for the unpredictability of staffing — last-minute sick calls, unexpected leave, turnover. For most businesses, 0.75–0.85 is realistic:
| Availability Factor | Meaning |
|---|---|
| 0.85 | Well-managed team, low turnover, good attendance |
| 0.80 | Average team, moderate turnover, occasional no-shows |
| 0.75 | High-turnover environment, frequent unplanned absences |
Worked Example: Café
Scenario: A café serves 120 customers during the morning peak (7:00–10:00 AM) and 80 during lunch (11:00 AM–2:00 PM). Each staff member can handle 18 customers per hour.
Morning Peak Calculation
| Factor | Value |
|---|---|
| Peak demand | 120 customers over 3 hours = 40 customers/hr |
| Staff per customer/hr | 1 ÷ 18 = 0.056 staff per customer/hr |
| Staff needed at peak | 40 × 0.056 = 2.2 → 3 staff |
Lunch Peak Calculation
| Factor | Value |
|---|---|
| Peak demand | 80 customers over 3 hours = 27 customers/hr |
| Staff needed at peak | 27 × 0.056 = 1.5 → 2 staff |
Total Staffing Requirement
The café needs 3 staff during the morning peak and 2 during lunch. With an availability factor of 0.80:
Total employees needed = 3 ÷ 0.80 = 3.75 → 4 employees
This accounts for the fact that at any given time, roughly 20% of your team may be on leave, sick, or unavailable.
Worked Example: Retail Store
Scenario: A retail store needs at least 2 staff on the floor at all times during trading hours (9:00 AM–5:30 PM, Monday–Saturday). One additional staff member is needed for stock replenishment.
Calculation
| Factor | Value |
|---|---|
| Minimum floor staff | 2 |
| Stock replenishment | 1 |
| Total per shift | 3 |
| Shift hours | 8.5 hours (including break) |
| Trading hours per week | 8.5 × 6 = 51 hours |
| Staff hours needed per week | 3 × 51 = 153 hours |
| Available hours per employee per week | 33 hours |
| Availability factor | 0.80 |
| Employees needed | 153 ÷ (33 × 0.80) = 5.8 → 6 employees |
Worked Example: Office
Scenario: An office has 25 employees. The business needs 1 receptionist, 1 office manager, and enough admin staff to support the 25 employees.
Calculation
| Role | Staff Needed | Notes |
|---|---|---|
| Receptionist | 1 | Covers 9:00–17:00, Monday–Friday |
| Office manager | 1 | Covers 9:00–17:00, Monday–Friday |
| Admin support | 1 per 20 employees | 25 employees = 2 admin staff |
| Total core staff | 4 | |
| Availability factor | 0.80 | |
| Employees needed | 4 ÷ 0.80 = 5 employees | Includes buffer for leave/sickness |
The Cost of Getting It Wrong
Under-Staffing
| Cost | Impact |
|---|---|
| Lost revenue | Customers leave when no one is available to serve them |
| Overtime costs | Existing staff work extra hours at overtime rates |
| Employee burnout | Overworked employees take more sick leave and eventually leave |
| Service quality decline | Fewer staff means longer wait times and lower customer satisfaction |
| Compliance risk | Overworked employees may breach maximum hour regulations |
Over-Staffing
| Cost | Impact |
|---|---|
| Direct labour cost | Paying for hours that are not needed |
| Reduced hours | Employees may not get the hours they need, leading to dissatisfaction |
| Lower margins | Labour is typically 25–35% of revenue — excess staff reduces profitability |
The balance is important: slightly over-staffed is usually cheaper than under-staffed, because the cost of lost revenue and overtime typically exceeds the cost of an extra employee.
Adjusting for Seasonality
Most businesses have seasonal demand patterns. Staffing levels should reflect this:
| Season | Adjustment |
|---|---|
| Peak season (Christmas, summer, school holidays) | Add 10–20% more staff via casuals or temporary hires |
| Shoulder season (autumn, spring) | Maintain base staffing |
| Quiet season (winter, post-holiday) | Reduce casual hours, offer annual leave |
| Events (local festivals, sporting events) | Temporary increase for specific dates |
Build a staffing calendar that maps demand by month and adjusts staffing levels accordingly. This prevents the common pattern of hiring permanently for peak demand (over-staffed 80% of the year) or running lean and scrambling during peaks.
How to Review Staffing Levels Quarterly
- Pull customer/task data for the past quarter. What was the actual peak demand?
- Review attendance data. What was the actual availability factor?
- Compare to your staffing model. Were you over or under-staffed at peak times?
- Check overtime. Did overtime costs indicate under-staffing?
- Check employee feedback. Are staff reporting being overwhelmed or underutilised?
- Adjust the model. Update the staffing level formula with actual data.
How Leave Balance Helps
Leave Balance’s analytics provide visibility into actual staff availability — who is on leave, who is sick, and what the real availability factor is for your team. This data feeds directly into your staffing model, replacing guesswork with facts.
For businesses using the Workforce tier, the rostering tool shows available staff at a glance, making it easy to see whether you have sufficient coverage before publishing each roster.
leave emails? Track your employee's leave with Leave Balance
Frequently Asked Questions
How do I calculate staffing for a 24/7 operation?
For 24/7 operations, calculate the minimum staff needed per shift, then multiply by the number of shifts per day. Apply the availability factor and add a buffer for rest days and leave. See our guide on 24/7 shift roster patterns for detailed patterns.
What is a good availability factor?
For most businesses, 0.80 is a realistic average. Well-managed teams with low turnover can use 0.85. High-turnover environments (common in hospitality) may need 0.75. Review your actual attendance data quarterly to set the right factor for your business.
Should I hire permanent staff or casuals for peak periods?
A mix of both. Use permanent staff for baseline coverage (the minimum you need every day) and casuals for peak periods (the extra demand during busy seasons). This keeps your fixed labour cost manageable while maintaining flexibility.
How often should I review staffing levels?
Quarterly at minimum. Demand changes faster than annual reviews can capture. If your business has strong seasonal patterns, review monthly during peak periods.
What if I cannot afford enough staff?
Prioritise coverage during peak demand hours and accept lower coverage during quiet periods. Use technology to automate tasks (self-service kiosks, online ordering, automated time tracking) to reduce the staff-to-customer ratio. Consider outsourcing non-core tasks (cleaning, bookkeeping) to free up internal staff for revenue-generating roles.