How many watts does a phone charger use?
By Tom Calder · Figures checked 4 November 2026 · Costs at 26.32p per kWh (Ofgem cap, 1 October to 31 December 2026)
A phone charger draws from about 5W for an old basic charger (not separately sourced) to about 45W (the fastest Samsung charger) at its peak, then tapers as the battery fills. An hour of charging costs at most 0.1p to 1p at 26.32p per kWh: a phone is one of the cheapest things you charge.
The numbers
- Running watts
- 5W to 45W
- Amps at 230V (most)
- 0.2A
- Energy an hour of charging at most
- 0.005 to 0.045 kWh
- Peak charger draw for an hour, an upper bound: charging tapers as the battery fills.
- Cost an hour of charging at most
- 0.1p to 1p
- On a 1kWh power station
- 14 hours to 2 days
- On a 2kWh power station
- 28 hours to 4.5 days
Costs use 26.32p per kWh, the Ofgem price cap's average Direct Debit electricity unit rate for 1 October to 31 December 2026. Your own rate is on your bill; on a fixed or time-of-use tariff it will differ.
How it’s used, and what that costs
Apple lists 20W to 40W USB-C adapters for fast-charging recent iPhones, and Samsung’s 45W Super Fast Charging 2.0 adapter supports its Plus and Ultra models. The fast part lasts only for the first part of a charge.
For a power cut, a charged power bank is the simplest answer: if phones are all you need to keep going, you may not need a power station at all.
In a power cut: how long a power station would run it
A 1kWh power station: 14 hours to 2 days. A 2kWh power station: 28 hours to 4.5 days. These use the same planning method as our power station pages: capacity × 90% usable depth × 85% inverter efficiency, divided by the load plus about 10W the unit uses itself (BLUETTI’s UK formula).
Output matters as much as capacity. The 7 units around 1kWh we list supply 1,500W to 2,000W continuously, and the 6 around 2kWh supply 2,200W to 3,000W, so check a unit’s rated output covers 45W before you rely on it.
On a power station, charge phones from the USB ports rather than a mains socket; EcoFlow notes the DC outputs avoid the inverter’s losses.
To size one for everything you’d want to keep running, use the sizer on our power stations comparison.
Compare: Laptop · Broadband router · LED light bulb
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Start free →Sources (8)
- Apple fast charge: 18W, 20W, 30W or greater USB-C adapters; 40W Dynamic Power Adapter with 60W Max
- Samsung UK: 45W Super Fast Charging 2.0 for Galaxy S22+/Ultra through S24+/Ultra and others
- EcoFlow: use DC ports for routers and phones to avoid inverter losses
- Ofgem: Energy price cap unit rates and standing charges, 1 October to 31 December 2026electricity 26.32p per kWh, Direct Debit; no VAT on electricity from 1 October 2026 to 31 March 2027
- BLUETTI UK — Elite 200 V2 (runtime formula: DoD 90%, η 85%, self-consumption about 10W)
- BLUETTI UK — Elite 100 V2 (self-consumption about 10W)
- Jackery UK — runtime formula (capacity × 0.85 ÷ watts)
- EcoFlow — test runtime before an emergency0.80–0.90 for AC; DC ports for routers and phones
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