How Much Data Does a Business SIM Need? 20GB vs Unlimited 5G (UK 2026)
How Much Data Does a Business SIM Need? 20GB vs Unlimited 5G (UK 2026)
A phone sips data. A laptop gulps it. That one fact decides whether your business needs a 20GB SIM or an unlimited 5G SIM.
Most businesses guess. Then they either pay for data nobody uses, or they run out in week three.
This guide shows you how to do the sums in five minutes. It is written by GleeSim, a boutique telecom company in Livingston, Scotland.
Want the answer done for you? Ask GleeSim for a free data check.
How much data does a business SIM need?
A business SIM used only in a phone for email, CRM, maps and a few video calls needs about 10GB to 20GB a month. A business SIM that feeds a laptop hotspot or a 4G/5G router needs 50GB or more, so unlimited data is the safer choice.
Think of data like water. Email is a dripping tap. Video is a garden hose. A router shared by six people is a fire engine.
How many GB does each work task use?
These are typical planning figures. Your apps and settings will change them a little.
|
Work task |
Data used (about) |
Size |
|
Email without big attachments |
A few MB a day |
Tiny |
|
Maps and sat nav |
5MB to 10MB an hour |
Tiny |
|
Voice-only Teams or Zoom call |
50MB an hour |
Small |
|
Web browsing and cloud CRM |
50MB to 150MB an hour |
Small |
|
Group video call in HD |
About 1GB an hour |
Big |
|
HD video streaming |
2GB to 3GB an hour |
Very big |
|
Laptop software update |
1GB to 5GB each time |
Very big |
The pattern is easy to see. Video and laptops eat the data. Everything else is small change.
Three real sums: 13GB, 71GB and "too much to count"
Sam, a field sales rep with a phone
Sam does email, CRM and sat nav every day. That is about 0.2GB a day, or 4.4GB over 22 working days.
Sam also joins two hours of video calls a week. That adds about 9GB a month.
Total: about 13GB. A 20GB business SIM gives Sam plenty of room.
Priya, a consultant who hotspots her laptop
Priya runs two hours of video calls a day through her hotspot. That is 44GB a month.
Her laptop browsing and cloud files add 1GB a day, so 22GB more. One software update adds 5GB.
Total: about 71GB. A 20GB plan would be empty in the first week. Priya needs unlimited.
A site office with six people on one router
Six laptops, a printer, video meetings and file uploads all share one SIM. This is mobile broadband (MBB), not a phone plan.
Usage runs into hundreds of GB a month. Do not put a capped SIM in a shared router.
GleeSim's Three Unlimited 5G Data SIM is built for this job. It is listed from £17 to £24.99 a month, with speeds up to 100Mbps and plug-and-play setup. Check the live page for current terms and fair-use rules.
The 15GB rule: when to move from 20GB to unlimited
Look at your last three bills. Then use this rule.
|
Your monthly usage |
What to buy |
|
Under 15GB, phone only |
20GB business SIM |
|
15GB to 20GB, or it jumps about |
Unlimited 5G business SIM |
|
Any laptop hotspot most days |
Unlimited 5G business SIM |
|
SIM goes in a 4G/5G router |
Unlimited 5G business SIM |
|
Machine sending small readings (M2M or IoT) |
IoT SIM in MB, not GB |
Why 15GB and not 20GB? Because one busy month will push you over. You want a safety gap.
There is a money check too. If unlimited costs only a few pounds more than 20GB, one overage charge wipes out the saving.
Ready to switch the heavy users? See GleeSim's unlimited 5G data SIMs.
Do not give every employee the same SIM
This is where most businesses waste money. They buy one tariff for the whole team.
Take a ten-person company. Seven people are like Sam. Three are like Priya.
Put seven on 20GB and three on unlimited. Everyone has enough, and nobody pays for data they never touch.
GleeSim builds this kind of mixed plan as a bespoke solution. One account can hold: