You ask a client a question and wait. A full second passes before they respond—not because they’re thinking, but because your voice took that long to reach them. Then you both start talking at the same time because the delay threw off the natural rhythm of conversation.
That’s latency. It’s the most frustrating VoIP problem because it doesn’t cause static or dropped calls—it makes every conversation feel unnatural. People talk over each other, pauses feel awkward, and the person on the other end starts to doubt whether you’re really listening.
The fix requires identifying where in the network the delay is happening and addressing that specific link. Here’s how to do that systematically.
Latency measures the time it takes for your voice to travel from your microphone to the other person’s speaker, measured in milliseconds (ms).
Latency thresholds:
| One-Way Latency | Call Experience |
|---|---|
| Under 150ms | Normal conversation—no noticeable delay |
| 150-250ms | Slight delay—occasionally talking over each other |
| 250-400ms | Obvious delay—difficult to hold natural conversation |
| Over 400ms | Unusable—constant interruption and frustration |
For reference, a traditional landline call has roughly 40-60ms of latency. VoIP over a well-configured network typically delivers 20-80ms. Problems start when something adds delay beyond that baseline.
VoIP latency isn’t caused by a single factor. It’s the sum of delays at multiple points:
Processing delay: Time for your phone or softphone to encode audio into data packets, and for the receiving device to decode them back into sound. Modern hardware handles this in 1-5ms. Older devices can add 20-40ms.
Network delay: Time for packets to travel across your local network, through your ISP, and to the destination. This is where most latency problems originate. Distance, routing efficiency, and network congestion all contribute.
Queue delay: Time packets spend waiting in line at routers and switches. When a router is processing a flood of data traffic, VoIP packets wait their turn—adding delay that varies with network load.
The total of these delays determines what you hear on the call. Fixing latency means reducing delay at whichever stage is contributing the most.
Before changing anything, establish what your current latency looks like and where it originates.
Ping your VoIP provider’s server to measure round-trip time:
Run pings at different times of day. If latency is low in the morning but spikes at 2 PM, the problem is likely network congestion during peak hours.
A traceroute shows every hop between your network and the VoIP server, with latency at each one. This tells you exactly where delay is being introduced:
Jitter is the variation in latency between packets. Even if average latency is acceptable, high jitter (over 30ms) causes choppy audio because packets arrive at unpredictable intervals.
Most VoIP latency problems originate inside your own network—not with your ISP or VoIP provider. Start here.
QoS tells your router to send VoIP packets first, regardless of what else is happening on the network. Without QoS, a large file upload or video stream can push VoIP packets to the back of the queue, adding queue delay.
Log into your router’s admin panel, find QoS or Traffic Prioritization settings, and give SIP and RTP traffic the highest priority.
For offices with significant data traffic, put VoIP devices on their own VLAN. This isolates voice packets from data traffic so they aren’t affected by what’s happening on employees’ computers.
Every router, switch, and firewall between your VoIP phone and the internet adds processing time. Audit your network path and eliminate unnecessary devices. Connect VoIP phones to a switch that’s directly upstream of your router rather than daisy-chaining through multiple switches.
Wi-Fi introduces 2-10ms of variable latency per hop, plus the possibility of interference and retransmission. For any device making VoIP calls, use an Ethernet cable. The consistency improvement is immediate.
Aging equipment adds processing delay that compounds across multiple devices.
Consumer-grade routers process packets slower than business-grade equipment, especially under load. If your router is more than 3-4 years old and your office has grown significantly since it was installed, it may be a bottleneck.
Look for routers with dedicated hardware for QoS processing rather than software-based QoS, which adds CPU load and delay.
Older VoIP phones may use slower processors and less efficient codecs, adding encoding/decoding delay. Modern IP phones handle HD audio codecs (G.722, Opus) efficiently with minimal processing time.
Business telephone services that include modern IP phones ensure your endpoint hardware isn’t contributing to latency.
Damaged Ethernet cables cause packet errors that trigger retransmission, adding delay. Replace any cable that’s visibly damaged or that you’re not confident in. Cat5e or Cat6 cables are inexpensive insurance against this category of problem.
If local network optimization doesn’t resolve the latency, the problem may be your internet connection.
When total traffic approaches your connection’s capacity, everything slows down—including VoIP. Monitor bandwidth usage during peak hours and compare to your plan’s capacity.
If you’re regularly using more than 70% of available bandwidth during business hours, it’s time to upgrade. Business internet services with symmetrical speeds and SLAs for performance provide the consistent low-latency connection VoIP requires.
Cable internet often delivers upload speeds 10-20x slower than download. Since VoIP uses upload and download equally, the limited upload becomes the bottleneck. Fiber internet with symmetrical speeds eliminates this.
Sometimes latency is high because your ISP routes traffic inefficiently—packets take a longer path than necessary. Share traceroute data with your ISP and ask them to investigate. Changing to a different ISP or adding a secondary connection can also resolve persistent routing issues.
After making changes, confirm they worked and set up ongoing monitoring.
Ping tests and traceroutes after changes should show measurably lower latency. Compare side-by-side with your pre-fix measurements.
Set up automated monitoring that alerts you when latency exceeds thresholds. This catches regressions before users notice them—a new device on the network, a firmware update that reset QoS settings, or ISP performance degradation.
1stConnect includes monitoring capabilities that track communication quality across your network, helping you spot latency trends before they become call quality complaints.
Ask your team if call quality has improved. Technical metrics matter, but the ultimate test is whether conversations feel natural again.
One-way latency under 150ms produces a natural conversation experience. Under 80ms is excellent. Above 250ms, conversations become noticeably difficult with people talking over each other.
Peak-hour latency typically indicates bandwidth congestion—either on your local network or with your ISP’s shared infrastructure. Configure QoS to prioritize VoIP during busy periods, and consider upgrading to a dedicated or fiber connection if the issue is ISP-side.
Yes. Wi-Fi adds 2-10ms of variable latency per hop and is susceptible to interference. For any device making business VoIP calls, wired Ethernet provides consistently lower latency. If Wi-Fi is unavoidable, use the 5 GHz band and ensure strong signal strength.
Yes. If your provider’s servers are overloaded or their network routing is inefficient, latency increases on their side. Traceroute data showing high latency at the provider’s hops indicates their infrastructure is the issue—contact their support with the data.
Latency causes conversational delay—you speak and there’s a pause before the other person hears you. Jitter causes choppy, fragmented audio. Packet loss causes gaps or robotic-sounding speech. Run diagnostic tests measuring all three to identify which is affecting your calls.
Ready to eliminate VoIP latency? Start with reliable business internet that delivers consistent low-latency performance, pair it with business telephone services optimized for call quality, and monitor your communication with 1stConnect.