Best VoIP Phone Systems for 100 Employees

A hundred employees sitting on a legacy phone system is an expensive problem hiding in plain sight. Maintenance contracts, per-line fees, and limited remote calling capability add up quickly. Moving to a cloud VoIP platform at this scale is not merely a technology upgrade, it is a meaningful cost and productivity decision. The challenge is that the market is crowded, and providers vary enormously in call quality, reliability, integrations, and actual price once you move beyond the headline per-user figure.

This guide cuts through the noise. Whether you are replacing an on-premises PBX, consolidating multiple office locations, or building a phone system from scratch for a growing company, here is what you need to know.

Why 100 Employees Is a Pivotal Threshold

At this headcount, you are squarely in the mid-market bracket. You are too large to tolerate consumer-grade reliability, but often not large enough to negotiate true enterprise contracts without some effort. The good news is that most leading VoIP providers treat 100 seats as a sweet spot, which means you will generally see competitive pricing, responsive account management, and access to premium feature tiers.

You will also need to think carefully about deployment. Do all 100 users work from one office, across multiple locations, or in a hybrid setup? The answer shapes whether you prioritise features like multi-site management, softphone apps, or advanced call routing. A distributed team of 100 has very different needs from a single-site contact centre of the same size.

Top VoIP Providers for Teams of 100

RingCentral

RingCentral is consistently rated one of the strongest all-round business phone platforms for mid-sized organisations. Its unified communications suite combines voice, video, messaging, and fax under a single licence. Best for companies needing a mature, feature-rich platform that integrates with tools like Salesforce, Microsoft Teams, and Google Workspace. At 100 users, RingCentral's Advanced or Ultra tiers unlock analytics, auto-call recording, and CRM screen-pop features. Pricing at this scale typically falls in the £20 to £35 per user per month range depending on tier and contract length.

Nextiva

Nextiva earns strong marks for call quality and customer support, two things that matter enormously when you have a hundred people relying on the phone every day. Its platform covers standard VoIP calling, video conferencing, team messaging, and a built-in CRM. Nextiva is particularly well suited to service-oriented businesses such as professional services firms, healthcare practices, or financial advisers. The interface is clean and onboarding is straightforward, which reduces IT overhead during rollout.

8x8

8x8 offers a compelling proposition for businesses with international calling needs. Its X Series plans bundle unlimited calling to a wide range of countries, which can deliver serious savings if your 100-person team includes staff or clients in multiple markets. 8x8 X4 and above plans include contact centre capabilities, making it a natural choice if a portion of your headcount operates in a customer-facing calling role. The platform also carries strong security and compliance certifications, which matter in regulated sectors.

Vonage Business

Vonage Business Communications provides a highly customisable environment. It appeals to teams that want to pick and choose add-ons rather than pay for an all-inclusive bundle. Best for technology-forward businesses that want API access and developer-friendly integrations. At 100 seats, Vonage can be competitive on price, though costs can climb if you stack multiple premium add-ons.

Zoom Phone

If your organisation already uses Zoom for video meetings, Zoom Phone is a natural extension. It layers cloud calling directly into the familiar Zoom interface, reducing the learning curve significantly. Pricing starts at around £10 to £15 per user per month for metered plans, making it one of the more affordable entry points at scale. It is best suited to companies where video-first collaboration is already embedded in daily workflows.

Key Features to Evaluate at This Scale

• Auto-attendant and IVR: Essential for routing 100 users efficiently without a full-time receptionist.
• Call recording and analytics, particularly if you manage a sales or support team that benefits from performance review.
• Mobile and desktop softphone apps, especially important for hybrid or fully remote workforces.
• CRM integrations with platforms like HubSpot, Salesforce, or Zoho, so call data flows into your existing records automatically.
• Uptime guarantees: look for providers offering 99.999% SLA commitments, which translates to less than six minutes of annual downtime.
• Number porting support, to migrate your existing business numbers without disruption.
• Admin portal quality, because managing 100 extensions, call groups, and ring strategies through a clunky dashboard wastes IT time constantly.

Understanding Total Cost of Ownership

The headline per-user price rarely tells the whole story. At 100 seats, you should also factor in hardware costs if you plan to use desk phones, setup and onboarding fees, international calling bundles if relevant, and any add-ons for call recording, analytics, or contact centre functionality. Requesting itemised quotes from at least three providers is strongly recommended before signing any contract. Our Best Business Phone Systems comparison resource is a good starting point for benchmarking providers side by side.

Many providers will negotiate contract terms more readily at 100 seats than at 10. Annual billing typically unlocks discounts of 15 to 25 percent compared to monthly rolling plans, and multi-year commitments can push savings even further.

Conclusion

Selecting the right VoIP phone system for 100 employees requires balancing call quality, feature depth, integration compatibility, and realistic total cost. RingCentral and Nextiva suit most general business needs, 8x8 excels in international and contact centre scenarios, Vonage appeals to developer-driven teams, and Zoom Phone is a smart fit where video collaboration is already central. Take the time to run trials, stress-test call quality across your actual locations, and compare contract terms carefully. The right decision here will serve your team reliably for years.

Next step

Compare business phone systems on Compare Bazaar

Review our Best Business Phone Systems blog, then get matched vendor quotes with no obligation.

Get Free Phone System Quotes Best Business Phone Systems →