VoIP vs Non-VoIP Numbers: What’s the Difference?

If a sign-up form has ever told you “this phone number can’t be used”, you have already run into the difference between VoIP and non-VoIP numbers. The two look identical: same length, same country code, same format. But to the website checking them, they are completely different things.

This guide explains what each type is, why so many websites reject VoIP numbers for verification, how to tell which kind you have, and when each one is the right choice.

The short answer

• A VoIP number works over the internet. It is issued by a VoIP provider or an app, not by a mobile network, and it isn’t tied to a SIM card.
• A non-VoIP number is a real mobile number issued by a carrier, on a SIM card, just like the number on your own phone.
• Websites that verify accounts by SMS generally trust non-VoIP numbers and often reject VoIP ones.

What is a VoIP number?

VoIP stands for Voice over Internet Protocol. Instead of travelling over a mobile network, your calls and texts are sent as data over an internet connection, and the phone number is assigned by the VoIP provider rather than by a carrier. That makes VoIP numbers cheap, flexible and quick to set up, which is why so many apps and phone systems use them.

Not all VoIP numbers are the same, though. Phone-number databases split them into two groups.

Fixed VoIP vs non-fixed VoIP

• Fixed VoIP numbers are tied to a physical line or device, such as a home or office phone service. Twilio, whose lookup service many websites use, describes a fixed VoIP number as “a virtual phone number associated with a physical device”, giving Comcast and Vonage as examples.
• Non-fixed VoIP numbers are created online, with no physical device involved. Twilio defines them as numbers “obtained online without requiring a physical device”, and gives Google Voice and Enflick (the company behind TextNow) as examples. Most free “second number” apps hand out non-fixed VoIP numbers: see virtual phone numbers and how to get a second phone number.

One naming trap to avoid: non-fixed VoIP is not the same as non-VoIP. A non-fixed VoIP number is still VoIP, and usually the kind websites are most suspicious of.

What is a non-VoIP number?

A non-VoIP number is a real mobile number issued by a mobile carrier and attached to a SIM card. When a website runs a carrier lookup on it, the result says “mobile”, exactly as it would for your personal number. That is the whole point: as far as the website can tell, a non-VoIP number is an ordinary phone.

VoIP vs non-VoIP at a glance

Why do websites reject VoIP numbers?

Phone verification exists to link an account to a real person. Non-fixed VoIP numbers can be created in seconds, often for free and in bulk, so they are popular with spammers and fake-account farms. To keep those out, many services run every number through a carrier-lookup service when you sign up. Twilio’s Lookup API, for example, reports a number’s line type as mobile, landline, fixedVoip or nonFixedVoip, among others, and the website decides which types to accept.

That is why the same number can work on one site and fail on another. Banks, payment apps, marketplaces and messaging apps tend to be the strictest; smaller sites may accept any number that can receive a text.

How to tell if a number is VoIP

The quickest way is a carrier lookup. Free tools such as Phone Validator show a number’s line type and carrier: “mobile” or “wireless” with a major carrier means non-VoIP, while “VoIP” means it isn’t. For the full walkthrough, including the API that businesses use, see our guide on how to check if a number is VoIP.

When to use each type

Use a VoIP number when you need:

• A business line that rings on your laptop, desk phone and mobile at once
• Call forwarding, voicemail transcription or cheap international calls
• A second number for everyday calls and texts with people you know

Use a non-VoIP number when you need:

• To receive a verification code from a site that blocks VoIP numbers
• To sign up for a service without handing over your personal number
• To keep work or project sign-ups separate from your own phone

Is a non-VoIP number anonymous?

No, and it isn’t meant to be. A non-VoIP number is an ordinary carrier number. It keeps your personal number away from the sites you sign up for and protects you from spam calls and data leaks, but it is not a way to hide unlawful activity. Our terms prohibit fraud, impersonation, spam and any other illegal use.

How to get a non-VoIP number

PVADeals rents real non-VoIP numbers from major carriers in the United States, the United Kingdom, Hong Kong, Indonesia and Australia. (Our Canadian numbers are VoIP, which most websites accept.) You can:

• Rent a short-term number for 20 minutes, to receive a one-off code
• Rent a long-term number for 3, 7, 14 or 30 days, and renew it for as long as you need
• Choose an All Services plan for a number that works on any website

You pay with crypto or a card through Stripe, and every charge is logged in your account. If an eligible number receives no SMS during the rental, its cost comes back automatically as store credit.

Just want to try one first? We also give away a free non-VoIP number. Everyone can read the codes it receives, so use it only for sign-ups that don’t matter. Comparing providers? See our comparison of non-VoIP number services.

Getting started takes a few minutes:

1. Create a free account and add credits.
2. Pick the country, the website you want to verify and the rental length.
3. Paste the number into the website.
4. Read the code on your PVADeals dashboard and finish verifying.

Need help with a specific case? See how to get a temporary phone number for verification, how to receive SMS online in the USA, or check the price estimator.