Heating Element Resistance Calculator

The formula

A heating element is a fixed resistance. Its resistance, voltage, and power are tied together by Ohm's law and the power equation, so if you know any two you can find the rest:

Worked example. A kiln element rated 2,500 W on a 240 V supply should read about 240² ÷ 2,500 = 23.0 Ω, and draw 2,500 ÷ 240 ≈ 10.4 A. Because Kanthal (FeCrAl) wire has a very small temperature coefficient of resistance, a cold reading on your multimeter lands very close to this operating value — so you can compare them directly.

Is my element still good?

Heating-element wire doesn't fail all at once. As FeCrAl wire oxidizes and ages, its cross-section thins and its resistance creeps up — so it draws less current, makes less heat, and your firings get slower until the kiln finally stalls short of temperature. Comparing a measured resistance to the target above is the quickest way to catch this:

• Within ~5% of target — healthy; keep firing.
• 5–11% high — aging; firings will lengthen. Order a set so you're not caught mid-project.
• More than ~11% high, or an open circuit (∞ Ω) — replace the element.

These thresholds are a practical field rule of thumb, not a substitute for your kiln manufacturer's spec. Always measure with the kiln unplugged and the leads disconnected, and compare each element in a multi-element kiln — a single odd reading points to the element that's gone.