Call centre service level is the percentage of calls answered within a target time. “80/20” means 80% of calls answered within 20 seconds. It is the most common promise a contact centre makes, and the most commonly miscalculated one, because there are several ways to treat callers who hang up. This guide explains the service level formula, shows how the same day can score anywhere from 72% to 80% depending on the method, compares service level with ASA and abandon rate, and helps you set a target your team can actually meet.
What service level means
Service level has two parts:
- A threshold in seconds, such as 20, 30 or 60.
- A target percentage, such as 80% or 90%.
Together they read as “X% of calls answered within Y seconds”. A bank’s card helpline might commit to 80/20. A hospital appointment line might accept 80/60. An emergency or code line should not be measured by service level at all, because every call must be answered at once.
Service level is useful because it combines speed and capacity in one figure. If you have too few agents for the calls arriving, the percentage falls quickly. For the full set of contact centre measures, see call centre KPIs and wallboards.
The service level formula, and its four versions
The simple version is:
Service level = calls answered within the threshold ÷ calls offered × 100
The difficulty is the abandoned calls. Some callers hang up within a few seconds, often because they dialled the wrong number or the IVR already answered their question. Others give up after a long wait. Each centre has to decide how to count them.
Take one day on a support queue with a 20-second threshold:
- 1,000 calls offered to the queue
- 900 answered, of which 720 within 20 seconds
- 100 abandoned, of which 30 hung up within 20 seconds
| Method | Formula | Result |
|---|---|---|
| A. All abandons count against you | 720 ÷ 1,000 | 72.0% |
| B. Abandons ignored | 720 ÷ 900 | 80.0% |
| C. Short abandons excluded | 720 ÷ (1,000 − 30) | 74.2% |
| D. Short abandons counted as met | (720 + 30) ÷ 1,000 | 75.0% |
The same day scores between 72% and 80%. None of these is wrong, but they are not comparable. Method B flatters a queue with many abandons, so avoid it. Method C is a fair middle path for most Indian contact centres: callers who gave up within the threshold are taken out of the count, everyone else is in.
Whatever method you choose, write it down, use it every month and use the same one when you compare teams, vendors or outsourcing partners.
Measure by interval, not just by day
A daily service level can look fine while customers had a bad morning. Suppose your queue scores 82% for the day, but between 10 and 11 am it scored 55%, because half the team took tea at the same time and a billing message went out at 10. The daily figure hides the hour that caused the complaints.
Review service level by half hour or hour. The intervals that miss the target tell you exactly where to add people, move breaks or change shifts. See call centre shift scheduling for building a roster from interval demand.
Service level, ASA and abandon rate
| Measure | Question it answers | Watch out for |
|---|---|---|
| Service level | What share of callers got through quickly? | Different abandon treatments give different numbers |
| Average speed of answer | How long did answered callers wait on average? | A short average can hide some very long waits |
| Abandon rate | What share of callers gave up? | Short abandons may be wrong numbers, not unhappy customers |
| Longest wait | What is the worst wait right now? | Spikes from a single stuck call |
Use them together. High service level with a high abandon rate usually means you are ignoring abandons in the formula. Low service level with a low ASA means a minority of callers are waiting a very long time. The average speed of answer guide goes deeper on that second case.
How to choose a service level target
- Start from the customer. How long will a caller to this line wait before giving up or calling a competitor? Sales and admission lines need short thresholds; scheduled support can use longer ones.
- Look at your current performance by interval. A target far above today’s numbers will not be met without more people.
- Price the target. Higher service levels need more agents, and the cost rises steeply near the top. Use Erlang C staffing to see how many agents each target needs for your call volume and handle time.
- Set separate targets per queue. A VIP or emergency queue and a general enquiry queue should not share one number.
- Pair it with an abandon target. Under 5% abandoned is a common goal for support lines.
80/20 is the classic figure. It is a reasonable default for many inbound lines, but it is not a law. 80/30 or 80/60 can be perfectly good if your callers are told what to expect and the longest wait is controlled.
How to improve service level
- Fix the roster first. Most misses come from too few agents in specific intervals.
- Move breaks and meetings out of peak hours. Track them with agent status and break codes.
- Cut handle time and wrap-up without rushing callers; see average handle time.
- Route smartly. Put a second group behind the main queue with agent priorities, so overflow is answered by trained staff instead of waiting.
- Call back missed and abandoned callers. A callback list keeps those customers even when service level slips.
- Use AI only as backup. When all agents are busy or the centre is closed, a BitVoice AI voice agent can answer, deal with simple requests and pass the caller back to an agent with a summary. Your people still answer first.
Service level in Voxdial Contact Center
In Voxdial Contact Center, you set the service level threshold in seconds (60 by default) and the service level target percentage (80 by default) in Call Center Settings, along with targets for answer rate, abandon rate, occupancy and first call resolution. The supervisor dashboard shows the service level, abandoned ratio, answer rate and average wait for today or any past day, with an hour-by-hour call chart. The wallboard shows a service level gauge against its target, an abandon rate gauge, SLA breaches, calls in queue and the longest wait, so the whole floor sees a slipping queue as it happens.
For the reports to read after the day ends, see call centre reports.
Want to set up service level targets and a live wallboard for your queues? Talk to BitVoice.
FAQs
What does 80/20 service level mean?
It means 80% of calls are answered within 20 seconds. The first number is the target percentage and the second is the time threshold in seconds.
How should abandoned calls be counted in service level?
Pick one method and keep it. A fair approach is to exclude callers who hung up within the threshold and count everyone else, so short wrong-number calls do not hurt the score but long waits do.
Is a higher service level always better?
Not always. Moving from 80% to 95% within the same time can need many more agents for a small gain in customer experience. Choose the target per queue based on what callers expect and what it costs.
Why is my daily service level fine but customers still complain?
The daily figure averages good and bad hours. Check service level by half hour; complaints usually come from a few intervals with too few agents.
