This tool helps call center managers, small business owners, and e-commerce sellers estimate required staffing levels. It accounts for call volume, average handle time, and operational hours to avoid under or overstaffing. Use it to plan shift schedules and control labor costs for your support team.
Staffing Calculation Results
How to Use This Tool
Follow these steps to generate accurate staffing estimates for your call center:
- Enter your total incoming calls per week in the first input field.
- Input your average handle time (AHT) per call, including talk time and after-call work, and select the correct time unit.
- Set your target service level (e.g 80% means 80% of calls answered within your target time) and target answer time in seconds.
- Fill in your operational hours per day, operational days per week, and expected shrinkage percentage (industry average is 20-30% for absenteeism, breaks, and training).
- Enter the standard full-time equivalent (FTE) hours per week for your region (typically 40 hours).
- Click the Calculate Staffing button to view your detailed results, or Reset to clear all inputs.
Formula and Logic
This tool uses the industry-standard Erlang C formula to calculate required staffing levels, adjusted for real-world operational factors:
- Traffic Intensity (A): Calculated as (Total Weekly Calls × AHT in Seconds) ÷ (Operational Seconds Per Week). This represents the volume of calls relative to your available operational time.
- Erlang C Calculation: We iterate through possible agent counts to find the minimum number of agents needed to meet your target service level, using the formula: SL = 1 - C(N,A) × e^(-(N-A) × t / AHT), where C(N,A) is the Erlang C formula, N is agent count, and t is target answer time.
- Shrinkage Adjustment: Raw agent counts are divided by (1 - Shrinkage%/100) to account for time agents are unavailable for calls (breaks, training, absenteeism).
- FTE Calculation: Total required staff hours are divided by your standard FTE hours per week to get the number of full-time equivalent employees needed.
Practical Notes
Call center staffing requires accounting for industry-specific operational factors to avoid costly errors:
- Shrinkage rates vary by industry: e-commerce support teams typically see 15-25% shrinkage, while B2B call centers average 25-35% due to longer training cycles.
- Target service levels are set based on business goals: 80/20 (80% of calls answered in 20 seconds) is standard for most customer support teams, while high-priority sales lines may target 90/15.
- AHT should include all post-call work, not just talk time: omitting after-call work will lead to understaffing and longer wait times.
- Operational hours should reflect when your team is actively taking calls: exclude pre-shift setup or post-shift wrap-up time from these values.
- FTE calculations assume standard 40-hour work weeks, but adjust this value if your region has different labor regulations or part-time staff.
Why This Tool Is Useful
Small business owners and call center managers face high labor costs, which often make up 60-70% of total call center operating expenses. This tool helps you:
- Avoid overstaffing, which wastes budget on idle labor during low-volume periods.
- Prevent understaffing, which leads to long wait times, poor customer satisfaction, and lost sales for e-commerce teams.
- Plan shift schedules in advance by providing clear FTE and daily agent requirements.
- Adjust inputs for seasonal spikes (e.g holiday sales for e-commerce) to scale staffing up or down quickly.
- Validate staffing plans with data-backed metrics instead of guesswork or outdated spreadsheets.
Frequently Asked Questions
What is a normal shrinkage rate for call centers?
Most call centers average 20-30% shrinkage. This includes 10-15% for breaks and lunch, 5-10% for training and coaching, and 5-10% for unplanned absenteeism. Adjust this value based on your team's historical data for more accurate results.
How do I calculate AHT correctly?
AHT (Average Handle Time) is the sum of talk time, hold time, and after-call work (ACW) divided by total calls. For example, if a call takes 3 minutes talking, 30 seconds on hold, and 1 minute of ACW, AHT is 4.5 minutes (270 seconds). Do not exclude ACW, as this will lead to understaffing.
Can I use this tool for 24/7 call centers?
Yes, enter 24 operational hours per day and 7 operational days per week. The tool will calculate staffing needs for round-the-clock coverage, and the FTE calculation will adjust for shift-based schedules automatically.
Additional Guidance
For best results, update your inputs monthly using your call center's actual performance data. Compare your calculated staffing levels to your current team size to identify gaps, and use the FTE output to plan hiring or shift adjustments. If your call volume varies significantly by day, calculate staffing for your peak day volume and use that as your baseline to avoid understaffing during busy periods.