Per-minute or per-call pricing?

Most of this category bills per minute. Rosie, Dialzara, AnswerConnect and Abby Connect all do, as do the developer voice platforms underneath them.

Smith.ai made per-call its explicit selling point. Goodcall went further and bills per unique caller per month, so the same person ringing three times costs once.

Slang.ai bills per location and publishes no volumes at any tier, which makes a like-for-like comparison impossible rather than expensive.

Pull last month's inbound calls and their durations. Most phone systems export this, and if yours does not, a week's sample is enough to see the shape.

Work out the mean length and the spread. A business whose calls average two minutes with almost none over five is a per-minute business. A business with a long tail of eight and twelve minute calls is not.

Run both models on the same month. Take the per-minute plan's included minutes and its overage rate, then the per-call plan's included calls and its rate, and compare the totals.

Then check the worst case rather than the average. The month that hurts is the busy one, and per-minute plans hurt most exactly when your phone is busiest.

Take an estate-planning attorney who gets 120 calls a month at around nine minutes each. That's 1,080 minutes. Now take a tire shop with 900 calls a month at about 70 seconds each, which comes to 1,050 minutes. On a minutes meter these two businesses look almost identical.

Price them on a per-minute plan charging 20 cents a minute and they pay $216 and $210. Switch to per-call pricing on GreetKeeper and they split apart. The attorney's 120 calls fit inside Starter at $49. Those 900 tire shop calls need Professional at $149 plus 150 overage calls at $0.35, so $201.50.

So the attorney saves $167 a month by paying per call, and the tire shop saves $8.50, which is close enough to call even. Long conversations are where per-call pricing earns its keep. A shop with short, frequent calls should compare carefully and might do just as well on minutes.

Ask every per-minute vendor how they round. If calls bill in whole-minute increments, a 70-second call is a two-minute call. The tire shop's 1,050 real minutes become 1,800 billed minutes, and that $210 bill becomes $360. Six-second or one-second increments are far kinder, and the pricing page rarely says which applies.

Find out when the meter stops. After a transfer to your own staff, some services keep counting while your employee talks, because the call still runs through their platform. On a per-minute plan that can turn one long handover into the most expensive call of the week.

Per-call plans have their own fine print, which is what counts as a call. With us, very short calls, robocalls and calls the assistant screens out don't count toward your plan, and the pricing page has the table. Put the same question to any other per-call vendor, and check your log for how many of last month's calls were over almost as soon as they began.

Whichever model you lean toward, do the sum on your busiest month of the past year. The average month flatters every plan.

GreetKeeper counts answered calls, so a long call and a short call cost the same. A caller who needs ten minutes gets ten minutes without anybody watching a meter.

The overage rate is printed next to each plan. Rosie, Slang, Ruby and AnswerConnect all publish a monthly price and leave the overage off the page entirely.

Three tiers, three rates: $49 for 200 calls at $0.45, $149 for 750 at $0.35, $349 for 2,000 at $0.25. Annual billing is two months free.