All Magnifi calls are billed by the minute. Call invoices are rounded down to the nearest minute (e.g. a call lasting 10:30 will be billed for 10 minutes). Callers are charged at the Expert's per-minute rate, multiplied by the call duration (in rounded-down minutes, minus any applicable free minutes granted by the Expert for first-time callers).
Any calls under 1 minute in duration are not charged - this is to account for potential issues where calls are interrupted or disconnected.