What Is a VoIP Phone?
A VoIP phone is a device or app that uses Voice over Internet Protocol to make calls: it turns your voice into data, sends it over an internet connection, and plays the other person's voice from data it receives. It does the same job as a landline or mobile phone, but the call travels over your network rather than a copper line or cell tower.
A VoIP phone on its own can't call anyone. It signs in to a VoIP service (a business phone system or calling provider), which gives it a number, connects its calls to other phones, and supplies features such as voicemail and transfers. Because the phone is tied to an account rather than a line, you can move it to another desk, another office, or another country and it keeps the same number. For the technology underneath, see what VoIP is.
How Does a VoIP Phone Work?
A VoIP phone works by registering with your provider over the internet, then sending and receiving calls as small packets of audio data. Your provider connects those calls to other VoIP phones or to the ordinary phone network.
- The phone registers: When it's switched on or the app opens, the phone signs in to your provider using SIP (Session Initiation Protocol) credentials, so the provider knows where to send your calls.
- You place or receive a call: The phone sends a SIP message with the number dialled, and the provider rings the other party, whether that's another app, a landline, or a mobile.
- Your voice becomes data: A codec compresses your voice into packets, usually every 20 milliseconds, and sends them over Wi-Fi, Ethernet, or mobile data.
- The provider connects the two sides: For calls to landlines or mobiles, the provider's gateway converts between VoIP and the phone network in both directions.
- Sound comes out the other end: The receiving phone puts the packets back in order and plays them as sound, fast enough to feel like a normal call.
Each call uses roughly 100 kbps in each direction, so an ordinary broadband connection handles several phones at once. A stable connection matters more than a fast one, and the VoIP bandwidth guide covers larger offices.
Types of VoIP Phones
There are six main types of VoIP phone. Most businesses mix two or three: apps for everyone, and desk or conference phones where people need them.
IP desk phones Physical phones with a handset, keypad, and screen that plug into the office network (often powered by the network cable itself, using PoE). They suit receptionists, front desks, and people who spend the day on the phone.
Softphones on a computer Desktop or browser apps that turn a laptop into a phone with a headset. They're ideal for remote and hybrid workers and anyone who works at a computer. Many work straight from the browser, so staff can call from a browser without installing anything.
Mobile VoIP apps (a "VoIP cell phone") Your provider's app on an iPhone or Android phone, which adds your business number alongside your personal one. This is how most small teams use VoIP today, and it's covered in more detail below.
Conference phones Speakerphones with several microphones for meeting rooms, so everyone around the table can be heard clearly.
Cordless IP (DECT) phones Handsets that roam around a shop floor, warehouse, or clinic while connected to a base station on the network.
Analogue telephone adapters (ATAs) Small boxes that connect an existing analogue phone or fax machine to a VoIP service, so older equipment keeps working.
VoIP Phone vs. Regular Phone
A VoIP phone differs from a landline or mobile phone in how the call travels and what the phone is tied to. Callers hear the same thing; the differences show up in flexibility and features.
# | VoIP phone | Landline phone | Mobile phone (regular calls) |
| Call travels over | Internet or office network | A copper phone line | The mobile carrier's network |
| Tied to | An account; works anywhere with internet | One line at one address | One SIM card |
| Numbers | Any area code or country; several on one device | The line's number | The SIM's number |
| One number on several devices | Yes | No | No |
| Business features | Transfers, menus, recording, voicemail to email, analytics | Basic | Basic |
| Needs | Internet and power | The line (traditionally powered from the exchange) | Signal and battery |
| Emergency calls | Use the address registered with the provider | Location tied to the line | Carrier location |
Using VoIP on Your Cell Phone
Any smartphone becomes a VoIP phone when you install a VoIP provider's app. The app adds a second line to the phone: your business number, with business features, next to your personal number. People sometimes call this a "VoIP cell phone", but it's simply a regular smartphone running a VoIP app.
How VoIP works on a cell phone
The app signs in to your provider and uses Wi-Fi or mobile data to make and receive calls on your business number. Incoming calls show which number they came in on, and outgoing calls show your business caller ID, so customers never see your personal number.
Why businesses use VoIP on cell phones
Keeps personal numbers private Staff can use their own phones for work without giving customers their personal numbers.
The number belongs to the business When someone leaves, the number and its call history stay with the company and can be reassigned.
Business features in your pocket Transfers, voicemail to email, call recording, business texting, and call logs that plain mobile calling doesn't offer.
A shared number for the team Several people can answer the same number, so a customer isn't stuck waiting for one person.
Lower cost than a second phone No second handset or second mobile contract to pay for.
Drawbacks to plan for
Connection quality Weak Wi-Fi or mobile signal causes choppy audio or dropped calls. Most apps switch between Wi-Fi and mobile data as you move.
Battery and data use The app runs in the background to receive calls, which uses some battery, and calls on mobile data use roughly 0.5–1 MB per minute.
Public Wi-Fi Use a provider that encrypts calls, and avoid sensitive calls on unsecured networks.
Emergency calls Use your regular mobile dialler for emergency calls, because it gives emergency services your location automatically.
How to set up VoIP on your cell phone
Step 1: Download the app Install your provider's app from the App Store or Google Play.
Step 2: Sign in Log in with your business account; your number is added automatically.
Step 3: Allow permissions Give access to the microphone, notifications, and contacts, so calls ring and caller names show.
Step 4: Set your preferences Choose your voicemail greeting, working hours, and whether calls ring on Wi-Fi only or on mobile data too.
Step 5: Test it Call in and out on Wi-Fi and on mobile data before you give the number to customers.
Features to Look For in a VoIP Phone
The right VoIP phone depends on how you'll use it. For desk and conference phones, these are the features that matter most.
- Provider compatibility: Check that the model is supported by your provider, ideally with automatic setup.
- HD voice: Wideband audio (often listed as G.722 or HD voice) makes calls noticeably clearer.
- Power over Ethernet (PoE): One cable for both network and power, with no plug adapter at each desk.
- Lines and programmable keys: More keys for monitoring colleagues' lines, transfers, and speed dials, useful at reception.
- Headset support: A headset port or Bluetooth for people who are on the phone all day.
- Wi-Fi option: Useful where running network cables to each desk isn't practical.
- Security: Support for encrypted calls (TLS and SRTP) and regular firmware updates.
For apps, look for a clear call screen, reliable notifications, switching between Wi-Fi and mobile data, and support for business texting.
How Much Does a VoIP Phone Cost?
A VoIP phone costs nothing extra as an app, because softphones usually come with the service, and roughly $50–$300 as a desk phone, depending on the model. You also pay for the VoIP service itself.
Item | Typical cost (2026) |
| Softphone app (mobile or desktop) | Usually included with the service |
| Entry-level IP desk phone | About $50–$80 |
| Mid-range IP desk phone | About $80–$150 |
| Advanced or executive desk phone | About $150–$250+ |
| Headset | About $15–$350 |
| Analogue telephone adapter (ATA) | About $50–$60 |
| VoIP service for a business | Most plans $15–$50 per user per month |
Some providers lease desk phones for a monthly fee instead of selling them. Over a few years, buying is usually cheaper, but leasing can include replacements. The full VoIP cost breakdown covers the service side of the bill.
How to Set Up a VoIP Desk Phone
Setting up a VoIP desk phone takes a few minutes once you have a VoIP service. Most providers now configure phones automatically.
Step 1: Check compatibility Confirm your provider supports the phone model.
Step 2: Connect it Plug the phone into a network port (or a PoE switch, which also powers it), or join it to Wi-Fi if it supports that.
Step 3: Provision it Add the phone to your account in the provider's dashboard, usually by entering its MAC address. The phone downloads its settings when it restarts. Otherwise, enter the SIP credentials the provider gives you.
Step 4: Register an emergency address Make sure the address on the account matches where the phone is used.
Step 5: Test calls Make and receive a few calls, check voicemail, and try a transfer.
How to set up VoIP phones covers the process for common models in more detail.
Pros and Cons of VoIP Phones
VoIP phones are cheaper and more flexible than landline phones, but they depend on your network and on power.
Pros:
- Use it anywhere: The number works wherever the phone or app has internet.
- One number, many devices: Desk phone, laptop, and mobile can all ring together.
- Business features included: Transfers, menus, recording, and voicemail to email.
- No new wiring: Phones use the existing network, and apps need no hardware at all.
Cons:
- Needs internet: No connection, no calls on that device, though forwarding to a mobile covers outages.
- Needs power: Desk phones and routers stop in a power cut unless they have battery backup; mobile apps keep working.
- Quality depends on your network: Busy Wi-Fi causes most choppy calls. QoS for VoIP helps.
Next step
Choose the VoIP Phone That Fits How You Work
A VoIP phone can be a handset on the front desk, a headset on a laptop, or the app on a phone you already carry. For most teams, apps cover everyone and desk phones are added only where they earn their place.
If you'd like to try it, every Calilio plan includes a free US, Canada, or UK local number and a monthly bundle of free minutes and SMS, on the mobile and desktop apps.
Frequently Asked Questions
Short answers to the questions people ask most about VoIP phones.
Can I use a VoIP phone as a regular phone?
Yes. A VoIP phone connected to a VoIP service can call and receive calls from any landline or mobile number, just like a regular phone.
Can a cell phone be a VoIP phone?
Yes. Install a VoIP provider's app and your smartphone makes and receives calls on a VoIP number over Wi-Fi or mobile data, alongside your normal mobile number.
What is the difference between a cell phone and a VoIP phone?
A regular cell phone call uses the carrier's network and your SIM's number. A VoIP call uses the internet and a number tied to your VoIP account, which can ring on several devices at once and comes with business features.
Do VoIP phones need a provider?
Yes. A VoIP phone needs a VoIP service to give it a number and connect its calls to other phones. The phone or app on its own can't place calls.
Do I need special phones for VoIP?
No. You can use the provider's app on the phones and computers you already own. Desk phones are optional, and an adapter can connect an existing analogue phone.
Do VoIP phones work during a power cut?
Desk phones and routers need power, so they stop unless they have battery backup. Mobile apps keep working on mobile data.