From this site

One project, every trade

Each calculator adds its lines to a single estimate — consolidated BOM, schedule and cash-flow included.

Open My Project →

Amps to Watts Calculator (230 V)

Convert current into power on a 230 V single-phase supply, as used across the UK, Europe and Australia.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax

Power

2990 W

High confidence

P = V × I at 230 V single phase, power factor 1 assumed. Single phase only. Three-phase power adds a factor of √3 and a power-factor term.

Conversion factor applied
230 W per A

Outside North America the single-phase supply is nominally 230 V, so the same current produces roughly twice the power it would on a US circuit — which is why a British kettle boils noticeably faster than an American one on the same current. The arithmetic is the same simple product, but two local details matter. The 13 A fuse in a UK plug is a protective maximum for the flexible cord, not a description of the appliance, so it should never be used as the current figure. And harmonisation set the nominal figure at 230 V while many real supplies still sit closer to 240 V, comfortably inside tolerance; that gap accounts for a few percent whenever a measured reading disagrees with a calculated one. For three-phase equipment none of this applies directly, since that relationship carries an additional root-three term.

Add the equipment this sizes

This result is a specification — 2,990 W — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • P = V x I for a resistive single-phase load
  • UK, EU and AU single-phase supply is nominally 230 V

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

Is UK mains 230 V or 240 V?
Nominally 230 V since harmonisation, though the tolerance band means real supplies often sit nearer 240 V. Calculations should use 230 V; if you are checking a measured figure against a nameplate, the difference explains a few percent of discrepancy.
Why does a 13 A fuse not mean a 3 kW appliance?
The plug fuse is the maximum the plug will pass before it protects the flex, not a statement of load. Many appliances fitted with a 13 A plug draw far less; a fused spur or a lower-rated fuse is often more appropriate for small loads.
How does this differ on a three-phase supply?
Substantially. Three-phase power is the line voltage times current times the square root of three, times the power factor. Applying the single-phase relationship to a three-phase load underestimates the power by a factor of about 1.73.