How this calculator works
Internet speed is a shared pipe. Everyone in your office — and every phone, camera and guest device — uses the same connection at the same time. This calculator adds up what each activity uses at your busiest moment, separately for download (data coming in) and upload (data going out), then adds headroom and rounds up to a tidy number you can compare with internet plans.
Speeds are in Mbps (megabits per second), the unit internet providers advertise. Where a vendor publishes a figure, we use it and say so. Where no official figure exists — like "general office use" — we use a labeled estimate you can change.
Where the numbers come from
| Activity | Default | Source |
|---|---|---|
| Teams video meeting (per person) | 2.5 Mbps up / 4 Mbps down (recommended) | Microsoft Learn — minimum 0.15/0.2, best 4/4 |
| VoIP phone call | 0.1 Mbps each way | Cisco: G.711 = 87.2 kbps per call over Ethernet, rounded up |
| Cloud practice-management / EHR user | 1.5 Mbps down / 0.4 up | One hosted dental system (Carestream PracticeWorks) advises at least 1.5 Mbps per simultaneous user; upload is our estimate |
| General computer use | 1.5 down / 0.5 up per active person | Estimate — email, web, Microsoft 365, light file sync |
| Guest Wi-Fi device | 1 down / 0.25 up | Estimate — best enforced as a speed limit on your firewall |
| Security camera uploading | 2 Mbps up | Estimate for 1080p video — check your camera's bitrate setting |
| Imaging uploads | GB per day spread over upload hours | Calculated: GB × 8,000 ÷ (hours × 3,600) |
Sources: Microsoft Learn, Prepare your organization's network for Teams (bandwidth requirements table, per endpoint); Cisco, Voice Over IP – Per Call Bandwidth Consumption; Carestream Dental, PracticeWorks hosted system requirements. Your own vendors' requirements override all of these — check what your EHR, practice-management, imaging and phone providers publish.
Download vs upload: why both matter
Most internet plans are sold on download speed, but offices increasingly need upload. Every video call sends your camera and screen share out; every VoIP call sends your voice out; cloud backups, imaging uploads to a cloud archive and cloud-recorded cameras all push data out continuously. When upload is saturated, calls are the first thing to suffer — voices go robotic, video freezes — even if downloads look fine.
If your calculated upload need is high relative to download, the tool flags it. That's a sign to look at fiber or a business plan with matching ("symmetrical") upload and download, rather than a bigger cable package.
Choosing sensible inputs
- Think about the busiest moment, not the average. A dental office at 8:30 a.m. might have every phone line ringing, the front desk in the practice-management system, a hygienist uploading X-rays, and the office manager on a Teams call.
- "Share online at the busiest time" accounts for the fact that not every person uses the internet heavily at the same moment.
- Imaging uploads are spread over the hours you enter. If your system uploads in bursts — say, right after each scan — the real peak will be higher. Scheduling big uploads overnight reduces daytime load.
- Headroom covers Windows updates, software downloads, growth and the fact that you rarely get 100% of the advertised speed. 25–50% is a common planning range.
A worked example
The calculator starts with a typical small practice: 12 staff on computers with 80% active at the busiest time, 4 phone calls, 2 HD video meetings, 8 people in a cloud practice-management system, 2 GB of imaging uploaded over the working day, and 5 guest phones. That adds up to about 40 Mbps down and 15 Mbps up at peak. With 30% headroom, it recommends a 75 Mbps download and 20 Mbps upload connection.
Notice where the load comes from. The two video meetings alone use 8 Mbps down and 5 Mbps up — more upload than all twelve staff browsing and emailing. Add four cloud-recorded security cameras at 2 Mbps each and the upload need jumps by another 8 Mbps before headroom. If your current plan's upload is only 10 or 20 Mbps, that's where calls will start to break up first.
Planning a backup internet line
The calculator also estimates what a failover connection needs to carry to keep the essentials running: phones, your cloud EHR or practice-management system, one video call and basic computer use for half the active staff. Guest Wi-Fi, cameras and imaging uploads are assumed paused during an outage.
A backup line works best when it doesn't share a weak point with the main one. Two services in the same cable bundle can fail together; a cellular (5G/LTE) router or a second provider using a different technology is more independent. The firewall should switch over automatically. That's exactly what kept a dental practice we work with running during internet outages — see the dental practice case study — and our EHR downtime and internet failover plan walks through the options.
Speed isn't the only thing that matters
Plenty of offices with fast internet still have bad calls. Other things to check:
- Latency and jitter — delay and variation in delay. Voice and video are sensitive to both.
- Quality of service (QoS) — firewall rules that put voice and video ahead of downloads and backups. Microsoft recommends QoS for Teams.
- Wi-Fi — weak coverage or crowded channels can ruin calls on a fast connection. Wire desk phones and workstations where you can.
- Guest separation — keep guest Wi-Fi on its own network (a VLAN) with a speed limit, away from clinical and office systems.
Our small office network, Wi-Fi and phone guide covers these in detail, and dental offices should read the dental imaging network guide.
Next steps
Print the results and compare them with your current plan (run a speed test during a busy time, not after hours). If you're choosing a new provider or adding a backup line, we can help size it and set up automatic failover — see our services or book a free call.