SIP trunk pricing follows three models: per channel (a fixed monthly fee for each simultaneous call, often with local minutes included), per minute (pay only for the minutes you use) and bundles (a set of minutes for a fixed fee). On top come number fees, setup fees and the billing increment. The cheapest model depends on how many calls you make at once and where you call.
How does SIP trunk pricing work?
A SIP trunk is a virtual connection between your phone system and a provider, measured in channels: one channel carries one call at a time. Providers charge for the capacity (channels), for the usage (minutes) or both, and separately for phone numbers. For the basics, see what is SIP trunking and VoIP channels and CPS.
Per channel vs per minute: which is cheaper?
| Model | How you pay | Cheaper when |
|---|---|---|
| Per channel (unmetered) | Monthly fee per concurrent call, local or national minutes included | Channels are busy most of the day with domestic calls |
| Per minute (metered) | Small or no channel fee, every minute billed | Volume is low or irregular, or much of it is international |
| Bundle | A fixed number of minutes per month, overage billed per minute | Volume is steady and predictable |
| Wholesale termination | Per minute by destination, from a rate deck | High volume, many destinations, own switch |
A quick test: divide the per channel fee by the per minute rate for the same calls. If each channel carries more minutes than that per month, per channel wins. International calls are almost always billed per minute whatever the plan.
What is included in SIP trunk cost?
- Setup fee: sometimes charged per trunk or per account.
- Channel fee: per concurrent call, or a fixed trunk fee with a channel limit.
- Number fees: monthly rental per DID, higher for toll-free and some countries. See what is a DID number.
- Outbound minutes: by destination and number type; calls to mobiles usually cost more than to landlines.
- Inbound minutes: often free on local numbers, charged on toll-free.
- Taxes and regulatory fees: in some countries, such as US federal and state fees on interconnected VoIP.
- Extras: CNAM, call recording, emergency calling, porting fees.
How does the billing increment change the price?
The billing increment decides how call length is rounded. At 60/60, a 10 second call costs a full minute; at 1/1 you pay 10 seconds. Offices with longer calls barely notice. Call centers and dialers with many short calls can pay far more on 60/60 billing: a 20 second call billed as 60 seconds costs three times its real length. See billing increments.
How to run a SIP trunk pricing comparison
- Export one month of CDRs: destinations, minutes, calls, peak concurrent calls.
- Count numbers by country and type.
- Price the month with each quote, including increments, number fees and taxes.
- Check quality on your top destinations before you decide, because a cheaper rate with lower ASR can cost more per completed call. See ASR, ACD and PDD.
For the non-price criteria, use the checklist in how to choose a SIP trunk provider. For per minute rates by destination, see VoIP termination pricing and what is a VoIP rate deck.
How can you lower SIP trunk cost?
- Right-size channels: check peak concurrent calls in your CDRs and stop paying for channels that never fill.
- Split traffic: keep a per channel plan for domestic calls and send international calls to a per minute route.
- Negotiate increments: per second billing often saves more than a lower headline rate.
- Drop unused numbers: number rental adds up across countries.
- Protect against fraud: set spending limits and block destinations you never call, so a hacked PBX cannot create a large bill. See toll fraud and PBX hacking.
Wholesale rates for high volume
If your outbound volume is large, buying termination by destination is usually cheaper than a retail SIP trunk plan. VoIPMatcher sources VoIP termination from its carriers at wholesale rates. Request a voice route quote with your destinations and monthly minutes.
Frequently asked questions
How much does a SIP trunk cost?
It depends on the country, the model and your traffic. Costs usually combine a fee per channel or per trunk, a monthly fee per phone number, and per minute rates for calls outside any bundle. Local calls in competitive markets are cheap, while calls to mobiles abroad and premium destinations cost much more. Price your own call profile to get a real figure.
Is SIP trunking cheaper than a phone line?
Usually, yes. SIP trunks replace physical lines with channels over your internet connection, so you pay for the capacity and minutes you use and avoid line rental per circuit. Savings are largest for multi-site businesses and international calling. You still need a reliable internet connection with enough bandwidth, which is a cost to include.
Why does SIP trunk cost differ by country?
Prices follow what local operators charge to terminate calls, taxes and regulatory fees, and how competitive the market is. Some countries have high mobile termination rates or restrict VoIP to licensed operators, which raises cost. Number rental also varies, because some countries require local address or identity documents for each number.
Are inbound calls free on a SIP trunk?
Inbound calls to geographic numbers are often included or very cheap, but not always. Toll-free numbers usually charge you per minute for every inbound call, because the caller does not pay. Some providers also charge for inbound calls forwarded from mobile networks. Check the inbound rate for each number type.
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