Guide
Billing increments: the rule that changes your bill by a third
Updated
Two providers can advertise almost the same per minute rate and bill you very differently, because the rate is only half the formula. The other half is the increment: the smallest unit of time the provider will charge you for. It is rarely on the pricing table and it is worth more than the rate difference between most of the providers here.
One second, thirty seconds, or unstated
Specialty Answering Service states it bills in one second increments. AnswerFirst calls it true one second billing with no rounding up. Ambs Call Center states that work time is calculated in 30 second increments and rounded up. PATLive and Abby Connect do not publish an increment at all.
That is three different disclosure standards in one market, and only the first two let you predict a bill.
What rounding costs on a short call
Take a 45 second call. Metered to the second at $1.23 a minute it costs about $0.92. Rounded up to a full minute at the same rate it costs $1.23. That is a third more for the identical call, and no rate comparison would show it.
The effect is worst exactly where answering services are most used: the quick message take. A business whose calls average under a minute can pay meaningfully more on a lower advertised rate, purely through rounding.
Ask for the increment in writing
Where the increment is not published, it still exists, and it is in the contract rather than on the website. Before signing, ask for it in writing along with three related questions: whether hold time is chargeable, whether the greeting and wrap up are inside the metered period, and what happens to a call that reaches the service and hangs up.
Providers who meter to the second generally answer these quickly, because the answer favours them. A vague answer to a specific question about billing is itself the answer.
The unmetered case
A per call provider has no increment, because nothing is metered. On Smith.ai a call is a call whatever its length, so the questions above collapse into one: what counts as a billable call. That is the equivalent thing to get in writing, and it is where a per call contract can surprise you: a wrong number, a robocall or a hang up may or may not be chargeable, and the pricing page is not where that is settled.