Free Tool
Wholesale Billing Increment Calculator
Paste the call durations from your own traffic and see what each billing increment would charge. Rounding happens per call, so the answer depends on the spread of your calls, not just the average.
1. Your call durations
Answered calls only, in seconds. Separate values with commas, spaces, or new lines.
The samples are illustrative lists of 20 calls, not real traffic.
2. Routes to compare
The values below are placeholders. Replace them with the minimum, step, and rate from each row of your deck.
Route A
Route B
Route C
Results
How the calculation works
A call no longer than the route's minimum is billed the minimum. A longer call is billed the minimum plus the time beyond it, rounded up to the next full step.
otherwise: billed seconds = minimum + ceil((duration − minimum) ÷ step) × step
cost = billed seconds ÷ 60 × rate per minute
For example, a 13-second call on 6/6 is billed the 6-second minimum plus 7 more seconds rounded up to 2 steps, which is 18 seconds. On 60/60 the same call bills 60 seconds. When the minimum is a multiple of the step, as in 60/60, 30/6, and 6/6, this gives the same answer as rounding the whole duration up to the next step. If a provider's minimum is not a multiple of its step, confirm how it counts the steps. The billing increments guide walks through the same rule with worked examples and the sources behind it.
What the average-only rows show
The last rows of the results apply each route's rule to a pretend set of calls that all last exactly the average. The gap between that estimate and the real result is the error you make by sizing a deal on average call duration alone. It can run in either direction, depending on how your calls are spread.
What this tool does not do
- It does not know any provider's rates, increments, or rounding method. It uses the numbers you type.
- It prices answered calls only. It does not model setup fees, minimum commitments, or failed-attempt charges.
- It does not judge route quality. A cheaper increment on a route with a poor answer rate can still cost more per conversation. See the route cost calculator and the route quality metrics guide.
Billing increment questions
What do 60/60, 6/6, 30/6, and 1/1 mean?
The first number is the minimum call duration, the shortest time billed no matter how short the call was. The second is the step size, the amount a call is rounded up by after that minimum. 60/60 bills a one-minute minimum in one-minute steps. 6/6 bills a six-second minimum in six-second steps. 1/1 bills per second with no extra rounding. Providers choose their own pairs, so read the pair on each row of the deck.
Why paste call durations instead of typing an average?
Rounding is applied to each call, not to the average. Ten calls of 30 seconds and nine calls of 10 seconds plus one call of 210 seconds both average 30 seconds. On 60/60 the first set bills 600 seconds and the second bills 780 seconds. An average cannot tell those apart, which is why the calculator also shows what an average-only estimate would have said.
How are fractional seconds handled?
Billing systems differ. Some drop the fraction, some round to the nearest second, and some count any fraction as extra time. The choice matters mostly at a boundary: a 60.1-second call on 60/60 bills 60 seconds if the fraction is dropped and 120 if any fraction counts. The calculator lets you choose between these three rules. If your deck does not state the rule, ask.
Where do I get my call durations?
From your call detail records (CDRs): the duration, in seconds, of each answered call. Unanswered attempts have no duration and are not billed, so leave them out. The calculator ignores zero and negative values.
Does this calculator use my provider's real rules?
No. It applies the minimum and step you type in, to the durations you paste. It does not know any provider's rates or rounding method, and the example values are placeholders. Take the numbers from your rate deck, and confirm the increment and the rounding method in writing.
Want the increment stated for every route?
Request a rate deck and check the minimum and step on each row against your own call durations.