How to Get the Best SIP Trunk Pricing for Your Business

SIP trunking can be an ideal communications technology for many businesses, typically offering great cost savings, solid scalability, and high call quality for outbound and inbound calls. However, like Voice over Internet Protocol (VoIP), not all SIP trunking services are created equal, and you rarely want to go with the lowest-cost plan on the market.

Some providers that claim to offer the lowest price may have the lowest monthly fees but charge high rates for extra phone numbers, E911 access, text messaging, long-distance calls, and more.

It’s not just about finding the lowest-cost SIP trunk provider, but also about finding the best value without being tricked into paying more than necessary. 

This SIP trunk pricing guide will help you figure out which service is best for you and your budget.

What Is SIP Trunking?

SIP trunking is a method that allows businesses to make and receive phone calls over the internet, replacing traditional phone lines.

Session Initiation Protocol (SIP) is an open standard for establishing telephone connectivity between devices and software. It provides the technical means for calling, answering, and maintaining internet-based voice calls between users.

SIP trunking works as a bundle of phone lines, but over the internet. Many small and large companies rely on trunk to provide their office with a backbone of business voice channels for everyone in the office, so long as you have enough SIP channels.

The term “trunking” refers to the technology or method to make and receive calls over the internet via a single, virtual phone line or “trunk.” 

SIP trunking provides VoIP connectivity between an on-premises private branch exchange (PBX) and the public switched telephone network (PSTN).

SIP trunk doesn’t use analog telephone equipment to route voice calls. Instead, it sends your voice calls over data networks. In other words, SIP trunks serve as an intermediary between your phone systems and a cloud phone service provider. That happens through a SIP server — a program that handles signaling and voice access to a centralized service, such as an IP PBX.

Simply put, a SIP trunk provides service to an office PBX, allowing all its phone extensions to connect to the outside world.

Functionality of SIP trunking:

Here’s how it works, step by step:

1. Connection to PBX: Your business uses a PBX system (Private Branch Exchange) to manage internal and external phone calls.
2. Virtual Phone Line (SIP Trunk): A SIP trunk acts like a digital version of a phone line, connecting the PBX to the internet.
3. Internet Transmission: Calls are converted into digital signals and sent over the internet, not through copper lines.
4. VoIP Provider Role: The VoIP provider receives the calls and routes them to the appropriate phone numbers, whether they are on mobile, landline, or other VoIP services.

Why businesses choose SIP trunking

Many businesses today are considering VoIP systems relying on SIP trunking for several reasons:

• Replacing legacy systems — Some offices use legacy phone equipment that now needs to be replaced. One such example is the primary rate interface (PRI) using integrated services digital network technology. These were sold in multiples of 23 lines each. Today, SIP trunking offers a lot more scalability thanks to its virtual switching instead of physical lines.
• Cost savings — SIP trunking service is significantly more cost-effective than traditional phone systems because traditional telephone equipment is expensive. Migrating analog phone systems to the cloud often results in significant savings.
• Increased scalability — You don’t have to worry about setting up physical phone lines for each new employee in the office, which can be expensive and time-consuming. Additional call paths ensure maximum reliability.
• Uses existing infrastructure — For those with an existing PBX or call center infrastructure, SIP trunks provide reliable voice service without requiring an overhaul. As the organization grows, just add more trunks.

These perks are easy to understand on their own. SIP trunking with reliable providers consistently allows for high-quality calls at a massive scale, even if everyone in the office is placing a call at the same time.

Businesses often compare Primary Rate Interface (PRI) and Session Initiation Protocol (SIP) when thinking about agility and scalability. They both help you connect to the telephone network but in entirely different ways.

Feature	SIP Trunking	Traditional PRI
Cost per line	Low, ~$20/month (metered)	High, ~$100/month (fixed)
Scalability	Easy (add/remove lines)	Difficult (requires hardware)
Flexibility	Uses existing internet	Limited routing options

SIP Trunk Pricing Models

There are two main ways SIP trunk providers price their services:

• Metered: This is similar to a traditional phone plan where you are charged by the minute for your calls. This can be beneficial for businesses that don’t make many calls, but it can also be unpredictable and expensive if you have a high volume of long or international calls.
• Unmetered: With this model, you pay a flat monthly fee for a specified number of channels (concurrent calls) and have unlimited calling to a designated area, typically including local and domestic calls. This is a good option for businesses that make a predictable number of calls each month. Some providers may also offer unlimited plans for international calls, but these are typically more expensive.

However, there are other factors that can affect SIP trunk pricing.

Factors Affecting SIP Trunk Pricing

Before choosing a SIP trunk service, it’s a good idea to understand the factors that impact pricing and how they drive the total cost associated with the system.

On average, most businesses can expect to pay between $10 to $25 per SIP trunk per month, but the pricing can vary based on your VoIP provider and your call volume. For those on a metered plan, many providers charge additional fees for phone numbers and assess different charges depending on the volume and origination/destination of phone calls.

The following factors are addressed below that impact pricing.

📌 1. Number of SIP Channels (Concurrent Calls)

• A SIP channel is like a line that handles one call at a time. The more simultaneous calls you need, the more channels you pay for.
• Some providers charge per channel, others include a bundle.

📌 2. Call Volume & Destination

• Outbound calling is usually metered unless you’re on an unlimited plan.
• Calls to:
  • U.S. and Canada are cheap or unlimited.
  • International numbers cost more — rates vary by country.

📌 3. Type of Plan

• Metered (pay-per-minute) is cheaper upfront but varies with usage.
• Unlimited calling plans cost more per channel but offer predictable billing.
• Hybrid plans combine a base fee with usage-based pricing.

📌 4. DID (Direct Inward Dialing) Numbers

• Each individual phone number (DID) usually costs $1–$2/month.
• More numbers = higher monthly cost.

📌 5. Inbound vs. Outbound Calls

• Some providers charge separately for inbound and outbound minutes.
• Toll-free inbound calling often costs more than local.

📌 6. Contract Length

• Long-term contracts often come with lower rates.
• Month-to-month offers flexibility but can cost slightly more.

📌 7. Add-On Products

• E911 (emergency calling), caller ID and CNAM, call recording, call data records, fax support, analytics, etc., may add extra costs.
• Some are flat fees, others are per-minute or per-user.

📌 8. Provider Infrastructure

• Some providers may charge more for (often embedded in usage or add-on fees):
  • Global reach
  • High reliability
  • Advanced tools/APIs

📌 9. Monthly Service Fees

• Some providers charge a flat monthly service fee in addition to per-channel or per-minute charges to cover:
  • Account maintenance
  • Access to portals or tools
  • Basic support or monitoring features

📌 10. Setup or Activation Fees

• Some providers charge one-time fees for:
  • Setting up your SIP trunks
  • Porting in existing phone numbers
  • Configuring PBX connections

📌 11. Additional PBX costs

• You must still use a PBX to operate the SIP trunk service, which means that you may incur additional PBX, including:
  • On-prem servers or cloud hosting
  • Systems engineers
  • Maintenance services
  • PBX software licensing
  • Security auditing

Make sure you’re accounting for all of these factors when reviewing your budget. Shop around and compare prices from different providers before selecting a SIP trunk plan. Be sure to factor in all costs, including the monthly fee, per-minute charges, phone number fees, and any additional features you may need.

SIP Trunk Pricing Comparison

Looking for a quick breakdown of SIP trunk provider service costs side-by-side?

Some companies offer straightforward and transparent pricing online, while others may require you to contact sales for customized quotes. That said, here’s the SIP pricing information you need:

SIP Provider	Key Features	Monthly Plan (Unlimited Calling Nationwide)	Per Minute Costs (Metered)
Nextiva	Easy setup and works with almost all PBX solutions  Straightforward pricing Includes a free local phone number and a toll-free number Superior reliability and customer support team	$24.95	$14.95 monthly – plus $0.008 per minute
Broadvoice	Omnichannel cloud contact center 24/7 tech and customer support  Features like call attendants and routing available	$17 per user per month (3-year contract required)	$11 monthly – 5,000 minutes included, and then $0.029 per minute (3-year contract required)
SIP.us	Fast and easy setup through an online dashboard Flexible options allow you to choose your own providers, including phones and carriers Microsoft Teams integrations	$24.95 per channel per month	N/A
Twilio	Easy scaling up or down No contracts, channel fees, or porting fees  Fraud prevention features Worldwide coverage	Need to talk to sales for an unlimited plan.	$1.15 – $2.15 per month per number  Outbound local calls: $0.0053 per minute (depending on location), Inbound local calls: $0.0034 per minute E911: $0.75 per number
Telnyx	Features such as call recording, emergency calling, and custom voice routing Five-minute set-up process Private multi-cloud network with excellent uptime	Need to talk to sales for an unlimited plan.	$1 per month per number Inbound local calls: $0.0035 per minute Outbound local calls: $0.005 per minute E911: $1.50 per month per number

SIP providers summary table

Provider	Best For	Pros	Cons
Nextiva	Midsize businesses	Support, simplicity	Less flexible for devs
Broadvoice	Steady-volume teams	Unlimited plans	Contract and connector fee
SIP.US	Cost-conscious PBX users	Flat-rate simplicity	Fewer modern tools
Twilio	Developers, global needs	Full programmability	Requires tech knowledge
Telnyx	Tech-savvy SMBs or enterprises	Price + power balance	Learning curve

Estimating SIP Trunk Usage

If you’re trying to assess how much you’ll spend with SIP trunking, you first need to consider your estimated SIP trunk usage.

Assessing call volume and needs

First, you’ll need to know the direct-dial numbers, known as direct inward dialing. These phone numbers allow your company to connect a block of phone numbers to your business’s PBX and its extensions so you can set up virtual numbers. Direct Inward Dialing is easily scalable as your business grows.

SIP trunking in action for a business:

You’ll also want to consider the cost of E911, which is part of the emergency phone system that automatically provides the location of the caller to 911 dispatchers. This has been a mandated service for VoIP providers since 2005.

Finally, think about your average inbound and outbound call volume. It’s important.

Knowing how many lines you use concurrently will affect the cost of a SIP trunk. Here’s a quick video that explains this.

Impact of seasonal trends on costs

Keep in mind that seasonal trends can cause significant swings in call volume, directly impacting SIP trunk pricing. For businesses with seasonal peaks, call volumes can rise by 30–40% or more during busy periods like holidays or special promotions.

SIP trunking’s scalability allows businesses to easily add channels during busy seasons and reduce them when demand drops, ensuring you only pay for what you need. This flexibility helps avoid over-provisioning and unnecessary expenses during slow periods while ensuring sufficient capacity during peaks – or as your business scales up. 

Tips to Lower Your SIP Trunking Cost

If you know you want to use a SIP trunk service but want to keep your costs down, consider these tips:

1) Choose the right pricing model

Consider your volume of inbound vs. outbound calls, average call minutes, and the features you need. This can help you choose the right monthly price point and the right pricing model.

If you generally have lower usage, a metered plan could work. But if you’re continuing to scale your voice usage, an unmetered SIP trunk plan offers the best value.

2) Bundle your services

Many SIP trunk providers, such as Nextiva, offer other VoIP or telecom services. You can bundle services and, in many cases, receive a discount on the total package.

3) Negotiate your contract

Work directly with a sales representative to find a custom plan for you. This may not be an option with all SIP trunk providers, but it never hurts to ask to find the best monthly fee.

For instance, if you don’t need direct inward dial numbers for every user, you could save on those extra costs.

4) Manage your call volume

While this can be tricky, there are strategies you can use to reduce call volumes. A lot of SIP trunk service and PBX systems are priced by concurrent call — or phone calls happening in real-time.

For example, having support and help desk sections on your website can answer commonly asked questions that customers may have otherwise called for. Live chat options on your site can also help mitigate a high call volume.

Trunking vs. Business Phone Service

You might be wondering about the differences between SIP trunking vs. an all-inclusive business phone system. While they both use VoIP, they differ in terms of features, functionality, and ease of use.

Business phone systems are hosted and managed entirely on the provider’s side. This is one option for VoIP phone lines, allowing you to leverage the power of the internet to increase call quality and overall scalability, even with simultaneous calls.

SIP trunking, on the other hand, potentially lets you use hardware that you already have in the office.

If you’re considering hosted PBX and SIP trunking, here are the key differences and comparisons you should keep in mind:

• Cost of initial setup — A hosted PBX costs less if you have no on-prem PBX equipment, low for SIP if you already own equipment.
• Ongoing costs — Expect to pay between $15 and $60 per phone line per month.
• Maintenance — Your VoIP provider handles maintenance and updates for hosted PBX.
• Company size — Hosted PBX systems are best for small businesses. SIP trunking is best for high-volume call settings, such as at a call center.
• Call quality — Hosted PBX is suitable for fewer concurrent calls, while SIP trunking tends to handle high volume much better, depending on your PBX solution.
• Security — SIP trunking offers equivalent security features at a technical level, but a Hosted PBX can be connected to Single Sign On and call logs are readily available to IT admins.

SIP trunking typically requires that businesses are technical, and it can become complicated relatively quickly. It may also lack customer support that IT managers (and users!) need, though this depends on the provider.

It’s worth considering that the cloud phone system by Nextiva can offer all the advanced features, call uptime, customer support, and ease of use that growing businesses need.

Choosing a Reliable SIP Trunk Provider

When choosing a reliable SIP trunk provider, look for the following:

• Reliability with redundant points of presence (POPs) and impressive uptime
• 24/7 customer support that’s available with knowledgeable, friendly reps
• Ease of use, including ways to scale your SIP channels instantly

Questions to Ask When Considering SIP Trunking Pricing

You should always ask a comprehensive set of questions to fully understand the costs and ensure they are getting the best value for their needs. Here’s a breakdown of relevant SIP trunk pricing questions, categorized for clarity:

1. Core Pricing Structure:

• What is the pricing model? (e.g., per SIP channel, per minute, flat rate, bundled, usage-based)
• What are the different pricing tiers or packages available?
• What is the cost per concurrent call (SIP channel)?
• What is the cost per minute for inbound and outbound calls? (Specify local, long-distance, and international rates.)
• Are there any setup fees or installation costs?
• Are there any monthly minimum commitments or volume discounts?
• Is there a free trial period or a money-back guarantee?

2. Call Charges & Usage:

• How are call minutes calculated? (e.g., rounded up to the nearest minute, actual usage)
• Are there separate charges for inbound and outbound calls?
• What are the rates for calls to specific countries or regions? (Request a detailed rate sheet.)
• Are there any surcharges for calls to mobile phones or premium numbers?
• What is the cost for toll-free numbers (800, 888, etc.)?
• How is call detail record (CDR) information provided, and is there a cost for it?
• Is there a limit on the number of concurrent calls?
• Are there any usage overage fees?
• Are there any charges for idle channels?

3. Features & Services:

• Are essential features included in the base price, or are they add-ons? (e.g., caller ID, call forwarding, voicemail, call waiting, E911)
• What is the cost of adding extra phone numbers (DIDs)?
• What is the cost of porting existing phone numbers?
• Are there any fees for advanced features like call recording, call queuing, or IVR?
• Is there a charge for SMS or MMS capabilities?
• What level of support is included, and are there additional charges for premium support?
• Is there a charge for access to an online portal to manage the SIP trunk?
• Is there a charge for failover or disaster recovery options?
• What codecs are supported, and are there any charges for specific codecs?

4. Network & Quality of Service (QoS):

• What is the provider’s network uptime guarantee (SLA)?
• What is the provider’s network latency and jitter performance?
• Does the provider offer QoS features like prioritization of voice traffic?
• What redundancy measures are in place to ensure service reliability?
• Where are the provider’s data centers located?
• How does the provider handle network congestion?
• Does the provider support secure SIP (TLS/SRTP)?

5. Billing & Payment:

• What is the billing cycle?
• What payment methods are accepted?
• Are there any hidden fees or charges not explicitly stated?

SIP Trunking Made Simple with Nextiva

Get reliable, cost-effective SIP trunking that connects your existing PBX to the cloud — with crystal-clear voice, seamless scalability, and zero hassle.

Nextiva’s affordable SIP trunk pricing lets you modernize your phone system without replacing your hardware. Say goodbye to expensive phone lines and hello to a smarter, cloud-powered solution that grows with your business.

Enjoy the power of business VoIP without the stress of complex setup or ongoing maintenance. With Nextiva, SIP trunking is just the beginning.

SIP Trunking FAQs