US Fax Number: How to Get One (Local or Toll-Free)

By Michael Chen · Published February 18, 2026 · Updated June 8, 2026 · 8 min read

Quick Answer: The easiest way to get a US fax number is through an online fax service. mFax Business lets you claim a local or toll-free US number in under 5 minutes — no hardware, no phone line, plans from about $9/mo (billed annually).

Getting a US fax number used to mean calling your phone company and waiting for a technician. Today it takes under five minutes online. You pick a local area code or a toll-free prefix, create an account, and faxes start arriving in your email.

This guide covers what a US fax number actually is, the difference between local and toll-free, how to get one, and what the setup looks like step by step.

What Is a US Fax Number?

A US fax number is a standard 10-digit phone number — formatted as (XXX) XXX-XXXX — that receives and sends fax transmissions. It works the same way a regular phone number does, but instead of voice calls it handles fax signals.

US fax numbers follow the North American Numbering Plan (NANP). The first three digits are the area code, which ties the number to a geographic region. Toll-free numbers use special three-digit prefixes (800, 888, 877, 855, 866, 833) instead of a geographic area code.

You don't need a fax machine or phone line to use one. Online fax services assign virtual fax numbers that route faxes to your email or a web portal — the number behaves identically to a traditional one from the sender's perspective.

Local vs. Toll-Free: Which Do You Need?

The biggest decision when getting a US fax number is whether to go local or toll-free. Both work the same way technically. The difference is what they communicate.

Local US Fax Numbers

A local number carries a geographic area code — 212 for New York City, 415 for San Francisco, 312 for Chicago. When a contact sees your number, they recognize where you operate.

Good for:

• Businesses serving a specific city or region
• Sole proprietors and freelancers who want to appear local
• Healthcare practices and law offices with regional clientele
• Building trust with customers who prefer local vendors

Toll-Free US Fax Numbers

Toll-free numbers (800, 888, 877, 855, 866, 833) have no geographic attachment. They work across all of North America and signal a national or enterprise-level presence. The "800" prefix has the longest history and highest recognition, but all toll-free prefixes are functionally identical.

Good for:

• Businesses with clients across multiple states
• Companies that want to project a national brand
• High-volume fax operations (insurance, finance, healthcare systems)
• Situations where the 800-prefix vanity number helps with recall

Side-by-Side Comparison

3 Ways to Get a US Fax Number

1. Online Fax Service (Recommended)

An online fax service gives you a virtual fax number that works entirely over the internet. You sign up, pick your number, and faxes arrive as PDFs in your email or app. No machine. No line. No toner.

This is the right choice for nearly everyone — individuals, small businesses, healthcare providers, and large enterprises alike.

How to get a US fax number through an online service:

Cost: $7–50/month depending on the provider and page volume. mFax Business starts at about $9/mo with usage-based pricing — build your own plan by choosing the exact seats and pages you need, pay only for what you use, no fixed tiers — and supports both local and toll-free US numbers.

2. VoIP Provider Add-On

If your business already runs on a VoIP phone system (RingCentral, 8x8, Vonage, etc.), check whether fax is included in your existing plan. Many unified communications platforms offer fax as an add-on.

How it works: Enable the fax feature in your provider's dashboard, choose a number (often included in business-tier plans), and send/receive faxes through the same web portal you use for calls.

Cost: Often $5–15/month extra, or bundled with business plans at $20–40/month for the full voice + fax package.

One limitation to know: Fax over VoIP uses the T.38 protocol, which is sensitive to network jitter and packet loss. If your internet connection isn't stable, fax delivery can fail silently. For compliance-sensitive documents (healthcare, legal), a dedicated online fax service is more reliable than a VoIP add-on.

3. Traditional Phone Line

You can get a dedicated fax line through AT&T, Verizon, or a regional carrier. A technician provisions a second phone number on your existing line, or installs a new physical line. You connect a fax machine or multifunction printer, and it works.

Cost: $30–80/month for the line, plus $100–500 upfront for hardware, plus paper and toner ongoing. Long-distance faxes cost extra.

This approach made sense when it was the only option. In 2026, it costs 2–4x more than online alternatives, requires maintenance, and offers less functionality. It's worth considering only if your organization has a regulatory or infrastructure requirement for physical fax lines.

How to Port an Existing US Fax Number

If you already have a fax number — from a traditional line or a previous online service — you can transfer it to a new provider without losing it. Your contacts keep the same number; faxes just start routing through a different system.

The porting process:

1. Sign up with your new provider and request number porting during or after setup
2. Sign a Letter of Authorization (LOA) — this is required by the FCC for all number transfers
3. Submit a recent phone bill (within 30 days) showing the account holder name, billing address, and the number being ported
4. Wait for transfer — typically 5–10 business days; your provider assigns a temporary number to use during this time
5. Old number activates on the new service; temporary number is retired

Cost: Porting is free at most providers, including mFax Business. Some carriers charge a porting-out fee — check with your current provider before starting.

US Fax Numbers for Healthcare and Legal

If you're in healthcare or law, the type of fax number matters less than whether your provider is compliant.

Healthcare (HIPAA)

HIPAA-compliant faxing requires:

• TLS encryption for all transmissions
• Business Associate Agreement (BAA) signed with your fax provider
• Access controls limiting who can view incoming faxes
• Audit logging tracking all send/receive activity

Any US fax number — local or toll-free — can be used for healthcare as long as the underlying service meets these requirements. mFax Business includes all of them and is designed for medical practices, hospitals, and health systems.

Legal (GLBA and Court Compliance)

Law firms that use fax for court filings and client records need end-to-end encryption, audit trails, and an ethical data handling policy. Federal Rule of Civil Procedure 5(b)(2)(E) permits service of process by fax. The fax number itself doesn't need to be special — what matters is that the provider supports encrypted delivery and maintains records.

For more on this, see our guide to HIPAA fax requirements and business fax services.

What Does a US Fax Number Cost?

mFax Business pricing:

• Usage-based pricing from about $9/mo — pay per seat ($3/seat/month) + pages ($4 per 100 pages/month), no fixed tiers, with 20% off annual billing
• Every plan includes a local or toll-free US number, web/mobile/desktop apps, API access, and HIPAA compliance + signed BAA — no per-tier gating

Additional US fax numbers are typically $4.99/month each across most providers.

Frequently Asked Questions

Do I need a US address to get a US fax number?

No. Online fax services assign US fax numbers based on your plan selection, not your physical location. Businesses and individuals anywhere in the world can get a US local or toll-free number through an online service.

Can I have more than one US fax number?

Yes. Most providers let you add additional numbers for $4–5/month each. This is common for multi-department businesses (one number per team) or healthcare practices with multiple providers.

Is a toll-free fax number free for people who send me faxes?

For traditional phone-based faxing, yes — the business owning the toll-free number pays for incoming calls. With online fax services, the sender's costs depend on their own fax plan. In practice, most online fax senders don't pay per-fax charges for outbound calls to toll-free numbers.

Can I use a US fax number to receive faxes internationally?

Yes. Any party with a fax capability — anywhere in the world — can send to a US fax number by dialing the country code (+1) followed by the 10-digit number. Your online fax service receives and delivers the fax regardless of the sender's location.

Get Your US Fax Number Today

Getting a US fax number no longer requires a phone company visit, a fax machine, or a dedicated landline. An online fax service gives you a local or toll-free number in under five minutes, with faxes delivered directly to your email.

For personal or occasional faxing, the mFax app is the simplest option — pay per fax or subscribe, and send from your phone.

For businesses, healthcare, and legal, mFax Business gives you a dedicated US fax number, HIPAA compliance, team accounts, and an audit trail — starting at about $9/mo.

Already have a number you want to keep? Start a port request when you sign up — your existing US fax number moves over in about a week, and nothing changes for the people who fax you.