A rate sheet shows a price per minute. What it often shows in smaller type is how the minutes are counted — and for outbound traffic, full of short calls, that small print can move your bill by half.
What the notation means
Billing is written as two numbers, both in seconds: the minimum you are charged for any answered call, then the increment in which time is counted after that.
- 1/1 — per second from the first second. A 42-second call is billed as 42 seconds.
- 30/6 — a 30-second minimum, then 6-second steps. A 42-second call is billed as 42 seconds; an 8-second call as 30.
- 60/1 — the first minute charged in full, then per second. An 8-second call is billed as a minute.
- 60/60 — every call rounded up to the next whole minute. A 61-second call is billed as two.
A worked example
Take 1,000 answered outbound calls with a mix that will look familiar to anyone who has run a campaign: plenty of quick hang-ups and voicemails, some short conversations, and a smaller number of real ones.
| Type of call | Calls | Real length |
|---|---|---|
| Hang-up or voicemail | 400 | 8s |
| Short conversation | 300 | 35s |
| Proper conversation | 200 | 2m 10s |
| Long call | 100 | 6m 20s |
The real talk time across those calls is 1,295 minutes. Here is what each billing scheme turns it into:
| Billing | Minutes billed | vs per-second |
|---|---|---|
| 1/1 | 1,295 | — |
| 30/6 | 1,460 | +12.7% |
| 60/1 | 1,767 | +36.4% |
| 60/60 | 2,000 | +54.4% |
Nothing about the calls changed. The same people, the same conversations, the same 1,295 minutes on the phone — billed as anything up to 2,000.
The cheaper rate that is not cheaper
Put two offers side by side. Route A charges 0.80p a minute on 60/60. Route B charges 1.00p a minute, per second.
- Route A: 2,000 minutes × 0.80p = £16.00
- Route B: 1,295 minutes × 1.00p = £12.95
The route that is 20% cheaper on the rate sheet costs 24% more on the invoice. Across 50,000 answered calls a month, that is about £150 a month for nothing.
Where the increment hurts most
- Outbound campaigns, because so many answered calls last only seconds.
- Transfers and short IVR legs, where one customer journey can create several brief calls.
- Much less on long inbound calls: a few seconds of rounding on a ten-minute support call barely registers.
Questions to ask before you compare rates
- What is the minimum and the increment — and is it the same for mobile and landline destinations?
- Is there a connection charge per call? A fee on every call behaves like a minimum, whatever the increment says.
- When does billing start? It should be when the far end answers. If you suspect it starts earlier, see false answer supervision.
- Can you test with your own traffic before committing?
Compare bills, not ratesTake one ordinary day of your own call records and price it under each provider’s rate and increment. It takes half an hour in a spreadsheet and it is the only comparison that tells you what you will actually pay.
VOIPNOX routes are billed per second, with no monthly fee and no minimum spend.
See pricing
