Sideline vs Google Voice: Complete Comparison for 2026

Looking for a second phone number for your business? Sideline and Google Voice are two of the most popular options, but choosing between them isn't straightforward. Both promise to keep your personal and business calls separate, but they take very different approaches—and neither offers the AI-powered features modern businesses need.

In this detailed comparison, we'll break down the real differences in pricing, features, and capabilities so you can make an informed decision. We'll also show you why thousands of businesses are choosing a third option that offers something neither Sideline nor Google Voice can match.

Sideline vs Google Voice: Quick Overview

What is Sideline?

Sideline is a business phone app that adds a second number to your existing smartphone. Unlike pure VoIP services, Sideline works through your mobile carrier's network, which means it uses your cellular minutes and data plan rather than relying solely on internet connectivity.

The app supports calling, texting, and voicemail, letting you keep business communications separate from personal ones without carrying a second device.

What is Google Voice?

Google Voice is Google's unified communications service that provides a single phone number across all your devices. It routes calls, SMS, and voicemails through the internet (VoIP), allowing you to manage everything from your computer, phone, or tablet.

For business use, Google Voice requires a Google Workspace subscription, which adds to the overall cost but integrates with Google's productivity suite.

Features: Google Voice vs Sideline

Both services cover the basics, but there are significant differences in what you get. Here's how the features compare:

Core Features Comparison

Where Sideline Wins

• Carrier-based reliability: Works through your mobile network, so calls work even with poor internet

• Team mobile numbers: Multiple team members can share a business line

• Simple setup: Download app, pick a number, start using it

Where Google Voice Wins

• Google ecosystem integration: Seamless connection with Gmail, Calendar, and Meet

• Desktop experience: Full web interface for managing calls from your computer

• Call recording: Built-in recording for inbound calls

• Video meetings: Google Meet included with business plans

Pricing: Sideline vs Google Voice

Pricing is where these two services really diverge. Let's break down what you'll actually pay:

Sideline Pricing

• Monthly: $9.99/month

• 6 Months: $49.99 ($8.33/month)

• Annual: $99/year ($8.25/month)

Includes: Second business number, toll-free inbound, call routing, voicemail transcription, and auto-reply.

Google Voice Pricing

Here's where it gets complicated. Google Voice for business requires two separate subscriptions:

1. Google Voice: Starting at $10/user/month (Starter plan)

2. Google Workspace: $6/user/month (required for Google Voice business)

Real cost: $16/user/month minimum

For a 5-person team, that's $80/month—and you still don't get features like AI call answering or shared inboxes.

The Hidden Cost Problem

Both Sideline and Google Voice have a fundamental limitation: when you can't answer, calls go to voicemail. According to research, 80% of callers won't leave voicemails—they'll just call a competitor instead.

That means the cheapest second line might actually be the most expensive if it's costing you customers.

Between Sideline and Google Voice, Which One is Best?

Choose Sideline if:

• You're a solo entrepreneur who needs a simple second number

• You work in areas with unreliable internet but good cell coverage

• You want the lowest possible monthly cost

Choose Google Voice if:

• You're already paying for Google Workspace

• You need deep integration with Gmail and Google Calendar

• Desktop calling is important to your workflow

Choose neither if:

• You miss calls that turn into lost revenue

• You need calls answered 24/7 (even when you can't answer)

• You want AI to qualify leads and capture information

• You have a team that needs to share a business line

An Alternative You Might Not Have Considered

While Sideline and Google Voice focus on being a second phone number, Ring4 approaches the problem differently: what if your business phone could actually answer calls for you?

Ring4 is an AI-powered business phone system that combines everything you'd expect from a virtual number—calling, texting, voicemail—with an AI receptionist that handles calls when you can't.

What Makes Ring4 Different

AI that actually answers: When you're busy, Ring4's AI receptionist picks up, has a natural conversation with callers, captures their information, and either schedules them or routes urgent calls through. No more voicemail black holes.

Call summaries and transcripts: Every call gets an AI-generated summary highlighting key points and action items. Know what happened without listening to recordings. Learn more about call summaries.

Team collaboration built in: Shared inbox lets your whole team see and respond to calls and messages. Assign conversations, leave internal notes, and never drop the ball on follow-ups.

Works everywhere: Mobile app, desktop app, or just forward to your existing phone. Use the same business number from anywhere.

Ring4 Pricing vs Sideline vs Google Voice

*Google Voice requires Google Workspace ($6/user/mo minimum) plus Google Voice ($10/user/mo minimum)

See our complete pricing page for all plan options.

Why is Ring4 Better than Google Voice and Sideline?

The fundamental question isn't which second line app is cheaper—it's which one actually solves your business problem.

If your problem is just wanting a separate number, Sideline or Google Voice will work fine.

But if your problem is missing calls that could be customers, neither solution actually solves it. You're still limited to answering when you're available, and voicemail when you're not.

Ring4 Solves the Real Problem

1. 24/7 coverage without hiring staff. AI receptionist answers when you can't—evenings, weekends, during meetings.

2. Lead qualification on autopilot. AI captures caller information, asks qualifying questions, and routes appropriately.

3. Team-ready from day one. Shared inbox means everyone sees what's happening, no conversations fall through cracks.

4. Professional setup support. Business plan includes guided onboarding to configure your AI receptionist properly.

Making Your Decision

Here's the bottom line:

• Sideline is the cheapest option for a basic second number with good cell coverage reliability.

• Google Voice makes sense if you already use Google Workspace and want tight integration.

• Ring4 is the choice when you need calls actually answered, leads captured, and team collaboration built in.

The best way to know is to try it. Ring4 offers a 7-day free trial with full AI receptionist capabilities—no credit card required. See what it's like to never miss a call again.

Ready to Stop Missing Calls?

Start your free trial and experience the difference AI-powered call handling makes.