Definition · AI Receptionists
Per-minute vs per-call vs flat billing
Also known as: per-minute pricing, per-call pricing, flat-rate pricing, usage-based call pricing
These are the three ways voice software charges. Flat billing is a fixed monthly fee for a bundle of usage. Per-minute billing charges for each minute of call time. Per-call billing charges a set rate for each answered call. The model — not the headline price — decides which vendor is cheapest at a given call volume.
A flat plan bundles a quota (minutes or calls) into a monthly fee, with an overage rate once the quota is exceeded. A per-minute model bills every minute of talk time at a marginal rate, often on top of a small or zero platform fee — common with developer voice platforms. A per-call model bills a fixed amount per answered call regardless of length. Many vendors are hybrid: a base subscription plus metered usage.
The models cross over. At low volume, usage-based pricing (per-minute or per-call) is cheapest because you pay only for what you use. As volume rises, the marginal rate compounds and a flat plan with a large included bundle becomes cheaper. The break-even depends on both how many calls you take and how long they run — a per-minute plan punishes long calls, a per-call plan punishes short ones.
This is why a sticker price is meaningless in isolation. The only honest comparison normalizes every vendor to the same workload — a fixed number of calls at an average length — and computes the effective monthly cost for each.