Watts to Amps UK Chart: 13 Amp Plug, Kettle, Shower, MCB Sizes
On UK mains, amps = watts ÷ 230. A 13 amp plug can supply 2,990 watts, a 3 kW kettle draws 13.0 amps, and a 10.5 kW shower draws 45.7 amps. This guide has the chart, the plug fuse for each load, and the MCB sizes. The UK watts to amps calculator converts any power, and the amps to watts calculator goes the other way.
Watts to amps on 230 V
Single-phase, power factor 1:
| Watts | Amps | Plug fuse | Smallest MCB |
|---|---|---|---|
| 10 W | 0.04 A | 3 A | 6 A |
| 60 W | 0.26 A | 3 A | 6 A |
| 100 W | 0.43 A | 3 A | 6 A |
| 500 W | 2.17 A | 3 A | 6 A |
| 690 W | 3.00 A | 3 A | 6 A |
| 1,000 W | 4.35 A | 5 A | 6 A |
| 1,150 W | 5.00 A | 5 A | 6 A |
| 1,500 W | 6.52 A | 13 A | 10 A |
| 2,000 W | 8.70 A | 13 A | 10 A |
| 2,500 W | 10.87 A | 13 A | 16 A |
| 2,990 W | 13.00 A | 13 A | 16 A |
| 3,000 W | 13.04 A | 13 A | 16 A |
| 4,000 W | 17.39 A | Too much for a plug: needs its own circuit | 20 A |
| 7,360 W | 32.00 A | Too much for a plug: needs its own circuit | 32 A |
| 7,500 W | 32.61 A | Too much for a plug: needs its own circuit | 40 A |
| 8,500 W | 36.96 A | Too much for a plug: needs its own circuit | 40 A |
| 9,500 W | 41.30 A | Too much for a plug: needs its own circuit | 50 A |
| 10,500 W | 45.65 A | Too much for a plug: needs its own circuit | 50 A |
Typical appliances
Typical power ratings; check the label on yours:
| Appliance | Watts | Amps at 230 V | Plug fuse |
|---|---|---|---|
| LED bulb | 8 W | 0.0 A | 3 A |
| Phone charger | 10 W | 0.0 A | 3 A |
| Laptop | 65 W | 0.3 A | 3 A |
| Television | 100 W | 0.4 A | 3 A |
| Fridge freezer (running) | 150 W | 0.7 A | 3 A |
| Microwave | 800 W | 3.5 A | 5 A |
| Fan heater | 2,000 W | 8.7 A | 13 A |
| Iron | 2,400 W | 10.4 A | 13 A |
| Kettle | 3,000 W | 13.0 A | 13 A |
| Dishwasher | 2,000 W | 8.7 A | 13 A |
| Tumble dryer | 2,500 W | 10.9 A | 13 A |
| Oven (electric, full) | 3,500 W | 15.2 A | Too much for a plug: needs its own circuit |
| Immersion heater | 3,000 W | 13.0 A | 13 A |
| Electric shower (8.5 kW) | 8,500 W | 37.0 A | Too much for a plug: needs its own circuit |
| Electric shower (10.5 kW) | 10,500 W | 45.7 A | Too much for a plug: needs its own circuit |
| Electric car charger (7.4 kW) | 7,400 W | 32.2 A | Too much for a plug: needs its own circuit |
Watts for each circuit rating
The most a circuit of this rating can supply at 230 V:
| Current | Watts | Kilowatts |
|---|---|---|
| 6 A | 1,380 W | 1.38 kW |
| 10 A | 2,300 W | 2.30 kW |
| 16 A | 3,680 W | 3.68 kW |
| 20 A | 4,600 W | 4.60 kW |
| 25 A | 5,750 W | 5.75 kW |
| 32 A | 7,360 W | 7.36 kW |
| 40 A | 9,200 W | 9.20 kW |
| 45 A | 10,350 W | 10.35 kW |
| 50 A | 11,500 W | 11.50 kW |
| 63 A | 14,490 W | 14.49 kW |
A ring final circuit of 32 A supplies all the sockets on the ring, so the total of everything plugged in should stay below 7.4 kW. Running several 3 kW heaters on one ring will trip the MCB.
Which fuse goes in the plug?
- 3 A for appliances up to about 690 W: lamps, TVs, chargers, small electronics.
- 5 A for appliances up to about 1,150 W: some small heaters and food mixers.
- 13 A for anything above that, up to 2,990 W: kettles, irons, fan heaters, toasters.
- Use the fuse in the manual. Never put in a larger fuse than the appliance asks for, since the fuse protects the flex.
Showers, cookers and car chargers
Appliances above 3 kW cannot use a plug: they are wired to their own circuit. An 8.5 kW shower draws 37.0 A and a 10.5 kW shower 45.7 A. A 7.4 kW car charger draws 32.2 A. The MCB, the cable size and the way the cable is run (in insulation or clipped to a surface) are set by the wiring regulations (BS 7671), and the work must follow Part P of the Building Regulations. Use a registered electrician.
How much does it cost to run?
Kilowatts times hours times your price per kWh. A 3 kW kettle that runs for a few minutes a day costs pennies, while a fan heater of 2 kW (8.7 A) left on for 4 hours uses 8 kWh. Use the electricity cost calculator with your own tariff.
Electrical work can start fires and kill. Use this for planning, and have a registered electrician do or check any wiring. Estimates only.
Frequently asked questions
How do you convert watts to amps?
Divide the watts by the volts. UK mains is 230 V, so 3,000 W ÷ 230 V = 13.0 A.
How many watts is a 13 amp plug?
2,990 watts at 230 volts, which is why most plug-in kettles and heaters are rated at 3 kW or less.
How many amps is a 3 kW kettle?
13.0 amps, just inside a 13 A plug (which has a 13 A fuse).
How many watts can a 32 amp ring main take?
7,360 watts (7.36 kW) in total across all sockets on the ring. Any single plug is still limited to 13 A.
How many amps is a 10.5 kW electric shower?
45.7 amps, so it needs its own circuit, normally on a 45 A MCB with 10 mm² cable (and more for a long run).
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and check the Building Regulations and any planning rules for anything structural or close to a boundary.