Attrition rate is the share of your agents who leave in a period. The basic formula is:
Attrition % = (Agents who left in the period ÷ Average headcount in the period) × 100
If 8 agents leave a team that averaged 202 agents during the month, attrition is 8 ÷ 202 × 100 = about 4.0% for the month. That one number drives hiring, training seats and the capacity you lose while new joiners ramp up.
This guide covers the monthly, rolling 12-month and early (first 90 days) formulas, one common annualising mistake, a worked example, and how to turn the rate into a hiring plan. It is written for team leaders, analysts and anyone preparing for a WFM or BPO interview.
The three formulas you need
| Metric | Formula | Use it for |
|---|---|---|
| Monthly attrition | Leavers in month ÷ average headcount in month × 100 | Monthly review, hiring plan |
| Rolling 12-month attrition | Leavers in last 12 months ÷ average headcount over 12 months × 100 | Annual view, trend, client reports |
| Early (new-hire) attrition | Hires who left within 90 days ÷ total hired in that cohort × 100 | Judging hiring quality and onboarding |
Average headcount is usually (opening headcount + closing headcount) ÷ 2. If you track headcount daily, use the daily average. Some teams divide by opening headcount instead. Either is fine, as long as you use the same method every time and the client agrees with it.
Voluntary and involuntary: also split leavers into resignations (voluntary) and terminations or absconding (involuntary). They have different causes and different fixes.
Worked example: a 200 agent team
A team opens the month with 200 agents, hires 12 and loses 8. It closes with 204.
- Average headcount = (200 + 204) ÷ 2 = 202
- Monthly attrition = 8 ÷ 202 × 100 = 3.96%, call it 4.0%
Now the annual number. Over 12 months the team had 96 leavers and an average headcount of 205.
- Rolling 12-month attrition = 96 ÷ 205 × 100 = 46.8%
Finally the early attrition. The team hired 40 agents in a quarter, and 8 of them left within 90 days.
- Early attrition = 8 ÷ 40 × 100 = 20%
Illustrative numbers, but realistic for a high-volume voice operation.
Why "monthly × 12" misleads
A quick way to annualise is monthly rate × 12. At 4.0% a month this gives 48%. It is close to the real rolling figure here (46.8%), but it is not exact, and it drifts further away as the monthly rate rises, because each month the pool of people who can leave gets smaller.
Compounding gives a more careful view of the chance that a single agent leaves within a year: 1 − (1 − monthly rate)^12.
These two methods answer different questions. Monthly × 12 is roughly "how many exits will I have to backfill?" when you keep headcount flat, so it suits hiring plans. The compounded view tells you "what share of one cohort is gone after a year". For client reporting, use the rolling 12-month figure from real data and avoid both shortcuts.
What is a good attrition rate for a BPO?
There is no single right number, and a global benchmark can mislead. Published guidance for contact centres commonly describes:
- Monthly: roughly 3% to 6% in steady centres, with anything above about 7% a warning sign.
- Yearly: roughly 25% to 45% in high-volume centres, under 20% as strong, and over 50% as risky.
- New hires (first 90 days): many teams aim for under 15% to 20%.
Treat these as rough ranges. Pay, shift pattern, location, local job market, client type and tenure mix all move the number. Build your own baseline by queue, site and tenure band, then watch the trend. For wider context, Indian companies overall reported attrition of 16.2% in 2025, the lowest in five years, according to Business Today, which shows how far contact centre numbers sit above the general average.
Turn the rate into a hiring plan
Attrition only matters if it changes your plan. Here is the simple version.
- Expected leavers per month = headcount × monthly attrition. For 200 agents at 4%, that is about 8 leavers.
- Add the early attrition on training batches. If 20% of a batch leaves in 90 days, a class of 40 gives you about 32 who stay.
- Hire for what you need on the floor, not for the leavers alone. A class of 40 at 20% early attrition gives about 32 agents, and training time comes before they take a live call.
- Remember ramp-up. A new joiner is not at full productivity on day one. The gap between a leaver walking out and a replacement reaching normal handle time is a real capacity cost. We break it down in The Hidden Capacity Cost of Attrition.
If you also need to plan headcount, check the capacity planning calculator and our guide on reducing headcount through attrition only.
Attrition is not shrinkage
These two get mixed up in interviews and reports.
- Attrition is lost people: agents who left.
- Shrinkage is lost time from agents who are still on the roster.
Do not put leavers into the shrinkage percentage. Keep them as separate lines in your plan. See Shrinkage in BPO: formula and worked example for the full comparison.
Common attrition mistakes
- Different denominators every month. Opening headcount one month, average the next. Pick one and stick to it.
- Counting transfers or promotions as leavers. Decide up front whether internal moves count, and say so in the report.
- Mixing voluntary and involuntary exits. The fixes are different.
- One number for the whole site. Early attrition in new batches can hide a healthy tenured team, or the reverse.
- Ignoring the gap between offer and joining date. First-day no-shows are a real part of early attrition. Track them separately.
- Planning only on the average. Attrition is lumpy: it spikes after appraisals, festivals and bonus pay-outs.
Quick checklist
- Agree the headcount method (average or opening) and keep it fixed.
- Report monthly, rolling 12-month and 90-day early attrition together.
- Split voluntary and involuntary leavers.
- Convert the rate into expected leavers and a hiring calendar.
- Keep attrition out of the shrinkage line.
Want to see where your planning is weakest? Try the free WFM Health Check.
FAQ
What is the formula for attrition rate in BPO? Attrition % = (Leavers in the period ÷ Average headcount in the period) × 100.
How do I calculate monthly attrition? Divide the number of agents who left in the month by the average headcount for that month, then multiply by 100. For 8 leavers and an average of 202 agents, that is about 4.0%.
How do I calculate annual attrition? Use the rolling 12-month method: total leavers over 12 months ÷ average headcount over those 12 months × 100. Monthly × 12 is a quick estimate only.
What is early attrition? The share of new hires who leave within a short window, commonly the first 90 days. Formula: hires who left within 90 days ÷ total hired in the cohort × 100.
What is a good attrition rate for a call centre? It depends on location, pay and work type. Many high-volume centres sit between 25% and 45% a year, and under 20% is considered strong. Build your own baseline and track the trend.
Is attrition the same as turnover? In most BPO conversations, yes: both describe people leaving. Some HR teams use turnover to include replaced staff and attrition for roles that are not refilled. Check your client definition.
Sources
- Contact Center Attrition Rate: What It Is and How to Calculate It, Customer Service Manager
- Attrition in BPO: A Deep Dive Into Employee Turnover, Call Centre Helper
- What attrition at 16.2%, lowest in 5 years, signals for India Inc in 2026, Business Today
--- Built by the WFM Helper team, from real large-scale, multi-client contact centre operations. WFM Helper, a ReadVela company.