Top pick
APC
Back-UPS Pro 1500VA Tower
A reliable line-interactive UPS sized for a single workstation, monitor and small NAS.
Desktop PC: ~48 min
4.6 £150 – £220
The UK's backup-power sizing site
When the grid goes dark, keep the lights on.
Tell us what has to stay on. The Power Sizer works out the watts and watt-hours, then shows which UPS, home battery or power station can actually run it — and for how long.
Real runtime maths
UK appliances & plugs
No sponsored rankings
Quick sizer · homelive
What must stay on during a 24-hour power cut?
Peak draw—
Energy / day—
Battery you need—
Best match
Fine-tune in the full Power Sizer
How it works
Buy the right size first time
Most backup-power buying guides stop at a list of products. We start with what you actually need to run, then match products to it using real runtime maths.
01 — Pick
Choose what must stay on
Routers, fridges, boilers, CPAP machines, servers, van fridges — with typical UK wattages built in.
02 — Measure
Get your real numbers
Peak watts, energy per day and the UPS or battery size you need, including inverter losses.
03 — Match
See what actually fits
Every product shows how long it runs your kit — and we tell you when something won't cope.
Browse by situation
Where do you need backup power?
Top picks
Find your size instead
Our favourites, with runtimes
Top pick
CyberPower
OL3000 Rack/Tower UPS
A 3000VA double-conversion UPS built for network cabinets and small server racks.
Desktop PC: ~3h 4m
4.5 £650 – £950
Top pick
EcoFlow
PowerOcean Home Battery System
Pairs with rooftop solar to power your whole home through a grid outage.
Fridge-freezer: ~5d 22h
4.6 From £4,500 (installed)
Top pick
Jackery
Explorer 2000 Plus
An expandable solar generator that's ideal for backing up essential home circuits.
Fridge-freezer: ~1d 5h
4.4 £1,400 – £1,900
Top pick
EcoFlow
Delta Pro
A high-capacity power station built for van conversions, RVs and cabins.
12V compressor fridge: ~6d 9h
4.7 £2,600 – £3,300
Top pick
Anker
SOLIX F1200
A mid-size power station for weekend trips, car camping and small cabins.
12V compressor fridge: ~2d 4h
4.6 £800 – £1,100
Power cut survival
Know before the lights go
Things most UK homes find out mid-power-cut
Landlines now need mains power
As UK phone lines move to digital (VoIP), home phones stop working in a power cut unless the router and handset have battery backup.
Your gas boiler needs electricity
Combi and system boilers need power for their pump and controls — no electricity usually means no heating or hot water.
Medical kit? Join the PSR
If someone at home relies on powered medical equipment, the free Priority Services Register gets you extra support during outages.
Report a power cut on 105
Call 105 free from any phone in England, Scotland or Wales to report or get updates on a power cut in your area.
Built for real life
From the server cupboard to the campsite
60-second Power Sizer
Storm on the way? Know exactly what you need.
Pick your devices, choose how long they need to run, and get a shortlist that genuinely fits — with runtimes for each.
Open the Power Sizer