VoIP Call Quality UK: How to Diagnose & Fix Poor Calls Quick Answer
Good VoIP call quality depends mainly on your internet connection, network configuration and VoIP service. If calls sound robotic, break up, lag, echo or drop entirely, the most common causes are high latency, jitter, packet loss, congested Wi-Fi, insufficient bandwidth or poorly configured network equipment.
As a practical business target, aim for:
Latency: below 150ms one wayJitter: below 30msPacket loss: below 1%, ideally as close to zero as possibleBandwidth: roughly 100 Kbps or more per simultaneous standard VoIP call, with spare capacity for other business traffic
If your network performs well but call quality remains consistently poor, the problem may sit with your VoIP configuration, hardware or provider.
See our business VoIP phone system comparison if you are considering changing your current setup.
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Authored by: Ally Cox (Business Technology & B2B Services Specialist 10+ Years’ Experience)
Reviewed by: James Ward (Telecoms Specialist, 12+ Years Experience)
Last Updated: September 2026
Key Takeaways
Latency, jitter and packet loss are three of the most important indicators of VoIP call quality.
High latency creates conversational delay and people talking over each other.
High jitter can make speech sound broken, robotic or distorted.
Packet loss causes missing words, audio gaps and dropped speech.
Poor Wi-Fi can cause bad VoIP calls even when your broadband speed looks good.
Ethernet connections are generally more predictable for fixed VoIP desk phones.
Quality of Service (QoS) can help prioritise voice traffic over downloads and other network activity.
Bandwidth needs should be calculated using simultaneous calls rather than total employees.
If your network is healthy but call problems continue, investigate your VoIP provider, configuration and hardware.
What Causes Poor VoIP Call Quality? VoIP calls are broken into small packets of data and carried across your network and the internet.
If those packets arrive too slowly, arrive at inconsistent intervals or fail to arrive at all, the quality of the conversation suffers.
Call problem Likely cause What to check first
Long delay before hearing the other person
High latency
Internet routing, congestion and connection quality
Robotic or distorted voice
Jitter or packet loss
Wi-Fi, congestion, router and packet-loss test
Words keep cutting out
Packet loss
Network stability and overloaded connections
Calls drop completely
Connectivity or configuration issue
Internet connection, router, firewall and provider logs
Call quality gets worse at busy times
Network congestion
Bandwidth usage and QoS configuration
Calls are poor only on Wi-Fi
Wireless interference or weak signal
Access points, coverage, channels and Ethernet testing
Only one user has problems
Device, headset or local connection
Handset, cable, Wi-Fi signal and software
Everyone has problems
Network or provider issue
Broadband, router, firewall and VoIP platform
Only external calls are poor
Provider/PSTN routing issue
Provider call logs and external routing
What Is Good VoIP Call Quality? There is no single number that guarantees a perfect call, but several network measurements are useful indicators.
Metric Good business target What poor performance sounds like
Latency
Below 150ms one way
Delay, awkward pauses and talking over each other
Jitter
Below 30ms
Choppy, robotic or uneven audio
Packet loss
Below 1%, ideally near 0%
Missing words, audio gaps and distortion
Bandwidth
Allow roughly 100 Kbps+ per concurrent standard voice call
Degradation when network usage increases
These should be treated as useful network-planning targets rather than absolute guarantees. Your codec, VoIP platform, network topology and other internet traffic also affect performance.
For a deeper technical explanation, see our guide to acceptable jitter and latency for VoIP .
What Is VoIP Latency? Latency is the time it takes voice data to travel across the network.
If latency becomes too high, the call can feel delayed even if the audio itself sounds clear so you might notice:
awkward pauses
people speaking over each other
delayed responses
a noticeable gap between speaking and hearing a reply
For high-quality real-time voice, a commonly used target is less than around 150ms one-way latency .
Higher latency does not necessarily make a call impossible, but the conversation becomes increasingly unnatural.
What Is Jitter? Jitter is variation in the time it takes individual voice packets to arrive.
Ideally, packets should arrive at consistent intervals – if some arrive significantly later than others, your VoIP system has to compensate using a jitter buffer. Excessive variation can result in:
robotic audio
broken speech
words arriving unevenly
distortion
A useful target for business VoIP is generally below 30ms jitter , although lower is better.
See our dedicated jitter and latency guide if your network test is showing inconsistent results.
What Is Packet Loss? Packet loss occurs when some of the voice data sent across the network never reaches its destination.
Unlike downloading a file, real-time voice cannot simply wait indefinitely for missing information to be retransmitted.
Packet loss therefore tends to produce:
missing words
audio clipping
short silent gaps
distorted speech
poor call quality
For high-quality business voice, aim for less than 1% packet loss and ideally as close to zero as possible.
How Much Bandwidth Does VoIP Need? VoIP itself does not normally require huge amounts of bandwidth.
The important factor is the number of simultaneous calls , rather than simply the number of employees.
As a broad planning guide:
Concurrent calls Approximate voice bandwidth guide
1 call
Around 100 Kbps+
5 calls
Around 500 Kbps+
10 calls
Around 1 Mbps+
20 calls
Around 2 Mbps+
50 calls
Around 5 Mbps+
These figures are only for voice traffic. Your connection also needs enough spare capacity for normal business use such as:
Microsoft Teams video
cloud applications
large file transfers
software updates
backups
web browsing
streaming
other employee internet traffic
See our full guide to how much bandwidth VoIP needs .
Why Can VoIP Be Poor Even With Fast Broadband? A fast speed-test result does not automatically mean your connection is good for voice.
A 500 Mbps connection with packet loss and unstable latency can provide worse call quality than a much slower but stable business connection.
VoIP depends on:
consistent latency
low jitter
minimal packet loss
stable upload performance
proper network configuration
This is why you should assess quality and stability , not just download speed.
Wi-Fi vs Ethernet for VoIP Wi-Fi can work perfectly well for VoIP, particularly for laptops and mobile devices, but it introduces additional variables.
Wireless performance can be affected by:
distance from the access point
walls and building materials
interference
too many connected devices
poor access-point placement
overlapping Wi-Fi channels
weak coverage
If a user has poor call quality over Wi-Fi, test the same call using Ethernet – if the problem disappears when wired, the issue is more likely to be your wireless network than the VoIP service itself.
For fixed desk phones, wired Ethernet normally offers a more consistent connection.
What Is QoS for VoIP? Quality of Service, or QoS, lets network equipment prioritise voice traffic over less time-sensitive data.
For example, without QoS, a large cloud backup or file download could compete with a live customer call for network resources.
Proper QoS configuration can help ensure voice packets are processed before less urgent traffic.
This is particularly useful for:
busy offices
call centres
sales teams
shared internet connections
sites with limited upload bandwidth
QoS cannot fix an fundamentally unreliable connection, but it can help manage congestion on a healthy network.
How to Improve VoIP Call Quality 1. Test your connection
Check latency, jitter, packet loss and bandwidth rather than relying only on a standard broadband speed test.
2. Test using Ethernet
If users normally connect through Wi-Fi, run a wired test. This quickly helps identify whether wireless performance is contributing to the problem.
3. Check for network congestion
Look for large downloads, backups, cloud synchronisation, video calls and other bandwidth-heavy activity during periods when voice quality deteriorates.
4. Configure QoS
Where supported, prioritise VoIP traffic through your router, switches and wider network.
5. Review the router
Old or low-spec routers can become a bottleneck when many users, calls and cloud applications share the same connection.
6. Improve Wi-Fi coverage
Check access-point placement, channel congestion and signal strength for employees using wireless VoIP.
7. Check phones and headsets
If one person has a problem while everyone else sounds fine, test another handset, headset, cable or computer.
8. Check your VoIP configuration
Review codecs, firewall settings, SIP configuration, NAT, session border controllers and provider recommendations where relevant.
9. Check broadband capacity
If your business has grown significantly since the phone system was installed, your connectivity may no longer match the number of concurrent calls and cloud applications.
10. Escalate to your VoIP provider
If your internal connection is stable but calls remain poor, ask your provider to investigate routing, platform performance, call logs and the affected numbers or destinations.
Is the Problem Your Broadband or Your VoIP Provider?
What you notice More likely cause
Internet and VoIP both slow down
Broadband or internal network
VoIP worsens when staff upload large files
Network congestion/QoS
Only Wi-Fi callers have problems
Wireless network
Only one handset has problems
Device or local connection
All calls to one destination/network are poor
Provider or external routing
Everyone experiences poor calls but internet tests are healthy
VoIP provider/configuration
Problems happen only at specific times
Congestion or provider capacity
Do not switch VoIP provider before checking the underlying network. Equally, do not continually upgrade broadband if the problem actually lies with the phone platform.
When Does a Business Need Better Connectivity for VoIP? Your existing business broadband may be perfectly adequate for a small hosted VoIP deployment.
You should consider stronger or more resilient connectivity if:
you operate a call centre
calls are business-critical
you have many concurrent calls
several sites share cloud systems
your upload performance is unstable
your connection regularly becomes congested
you need guaranteed performance or stronger service levels
you need automatic internet failover
Depending on the business, this might mean FTTP, dedicated business broadband, secondary 4G/5G connectivity or a business leased line .
Should You Use a Leased Line for VoIP? You do not automatically need a leased line just because you use VoIP.
For a small office with relatively few simultaneous calls, good-quality business broadband or FTTP may be sufficient.
A leased line becomes more relevant where:
voice is business-critical
you have many concurrent calls
you operate a contact centre
you need symmetrical upload and download capacity
you require stronger service guarantees
you have significant cloud and voice traffic sharing one connection
See our guide to leased line costs if your connectivity is becoming the limiting factor.
Can Changing VoIP Provider Improve Call Quality? Potentially, but only if the provider or its configuration is actually the problem.
Different providers can vary in:
network architecture
call routing
platform resilience
support quality
monitoring
hardware configuration
failover options
implementation quality
If your network consistently meets good latency, jitter and packet-loss targets but users continue to experience poor calls, comparing alternative providers is reasonable.
Our main Business VoIP Phone Systems UK guide compares hosted VoIP, Microsoft Teams Phone, SIP and other business phone-system options.
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VoIP Call Quality Troubleshooting Checklist If your calls sound poor, work through these steps in order:
Check whether the problem affects one user or everyone.
Record when the problem occurs.
Test latency, jitter and packet loss.
Check available upload and download capacity.
Run the same call over Ethernet instead of Wi-Fi.
Check whether backups, downloads or video traffic coincide with the problem.
Review QoS configuration.
Check the user’s headset, phone or computer.
Restart or review routers and network equipment where appropriate.
Test more than one call destination.
Review provider status and call logs.
Escalate persistent problems to the VoIP provider.
VoIP Call Quality for Remote Workers Remote employees can introduce additional variables because the business may not control their home broadband, router or Wi-Fi.
For important remote-working roles:
test the employee’s actual home connection
encourage Ethernet where practical
avoid very weak Wi-Fi locations
use appropriate headsets
check whether VPN routing affects call performance
provide a backup option for important users
See our guide to VoIP for remote teams for more detail.
Does VoIP Security Affect Call Quality? Security and call quality are separate issues, but poor configuration can sometimes affect both.
Firewalls, VPNs, session border controllers and security policies need to be configured correctly so that voice traffic is protected without being unnecessarily delayed or blocked.
See our VoIP security checklist when reviewing a business phone deployment.
Our Verdict: How Do You Improve VoIP Call Quality? Start with the network before blaming the phone system.
Check latency, jitter and packet loss, then test wired versus Wi-Fi performance and identify whether congestion coincides with the problem.
As practical targets, aim for:
latency below 150ms one way
jitter below 30ms
packet loss below 1%
enough spare bandwidth for all concurrent calls and normal internet use
If those measurements are consistently healthy but calls remain poor, investigate your VoIP configuration, hardware and provider.
If the system itself no longer meets your business requirements, compare alternatives through our business VoIP phone system guide .
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Frequently Asked Questions What is good VoIP call quality?
Good VoIP provides clear, consistent speech without noticeable delay, robotic audio, missing words or dropped calls. Network quality depends particularly on latency, jitter and packet loss.
What is a good latency for VoIP?
A commonly used target for high-quality voice is less than around 150ms one-way latency. Higher latency can introduce noticeable conversational delay.
What is a good jitter level for VoIP?
Keeping jitter below around 30ms is a useful target for business voice. Lower jitter means voice packets are arriving at more consistent intervals.
How much packet loss is acceptable for VoIP?
Packet loss should ideally be as close to zero as possible. Keeping it below around 1% is a common target for good-quality business voice.
How much bandwidth does a VoIP call need?
A standard VoIP call may require roughly 100 Kbps or more in each direction depending on the codec and service. Calculate requirements based on simultaneous calls and allow spare capacity for normal business internet use.
Why does my VoIP sound robotic?
Robotic or distorted audio is commonly associated with jitter, packet loss, poor Wi-Fi or network congestion.
Why do people keep talking over each other on VoIP?
High latency can introduce enough conversational delay that callers begin speaking before hearing the other person’s response.
Why do my VoIP calls keep cutting out?
Audio cutting out can result from packet loss, unstable Wi-Fi, congestion, broadband interruptions, hardware issues or a VoIP-provider problem.
Is Ethernet better than Wi-Fi for VoIP?
Ethernet usually provides a more predictable connection for fixed phones, although properly designed business Wi-Fi can also deliver good VoIP performance.
Does QoS improve VoIP calls?
QoS can improve call stability when voice traffic competes with other internet activity by giving real-time voice packets greater priority. It cannot compensate for a fundamentally unreliable connection.
Can slow broadband cause bad VoIP quality?
Yes, but raw speed is only one factor. A fast connection with high jitter or packet loss can still produce poor calls.
Do I need a leased line for VoIP?
Not necessarily. Many small businesses can run VoIP over business broadband or FTTP. Leased lines are more relevant where call volumes are high, connectivity is business-critical or stronger performance guarantees are needed.
Can changing VoIP provider fix poor call quality?
It can if the provider, routing or platform configuration is causing the issue. Check your local network and broadband first so that you do not switch providers without addressing the actual problem.
How can I test my VoIP call quality?
Test latency, jitter, packet loss and available bandwidth under normal working conditions. Ideally test at busy times as well as when the network is quiet.
Compare Business VoIP Systems If your current phone service has persistent quality problems despite a healthy network, it might just be time to compare the system itself.
See our business VoIP phone systems pillar , compare business VoIP providers or review hosted VoIP solutions .
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Hi, I’m Ally Cox , a senior copywriter and blogger at CompareYourBusinessCosts.co.uk, the UK’s trusted platform for comparing business services.over a decade of experience in the B2B sector, I specialise in simplifying complex topics like leased lines, VoIP, business energy, HR and payroll solutions, accounting software, and EPOS systems .HR, copywriting, and business operations- from clocking-in systems to card machines and office technology .informed, confident decisions when choosing products and services that improve efficiency and save money.
