Resistance Wire Calculator

Wire diameter · Length · Resistance · Surface load

Diameter formulad = (1 / k_d) · ³√( I² · ρ · C_t / p_s )

Input Parameters

Alloy grade

Power P

Voltage U

Element temperature

°C

Target surface load p_s

W/cm²

Temperature correction C_t (auto by alloy & temp, editable)

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Specified wire dia. d (optional · verify length & load)

Required length and actual surface load are recomputed for this diameter.

Stainless rod OD (mandrel · adjustable)

Pitch ratio S/d (stretched pitch · adjustable, manual 2–4)

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Ratio of pitch S to wire dia. d; gives stretched length L = (S/d)·L_N.

Calculated wire diameter d

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Required length l —m Wire mass —kg

Current I = P/U

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Resistivity ρ

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Hot resistance R_T

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Cold resistance R₂₀

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Resistance/m R′

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Wire length l

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Actual surface load

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Wire mass

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Helical coil dimensions (wound on stainless rod)

Inner dia. = rod+1

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Mean dia. = inner+wire

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Outer dia. = mean+wire

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Mean/wire D/d

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Turns N

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Close-wound L_N = N·d

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Stretched L = (S/d)·L_N

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Pitch ratio S/d

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Wire detail (shared by both methods)

Application cases (three heater shapes)

密绕长度 L_N = — mm；Stretched L = (S/d)·L_N = — m（密绕长度经 2–4 倍拉伸后的线圈物理长度，非线长 l），拉伸螺距 S = — mm。逐形状校验拉伸长度能否在加热器内合理分布（可布丝长度 ≥ 拉伸长度）。

Cylinder heatertwo wiring methods

Inner dia. ID

Wall t

Height H

Lead-out gap (Method 1)

Top/bottom edge (Method 2, 10–30)

Actual columns N (Method 2)

cols

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Half-cylinder heatertransverse / longitudinal

Inner dia. ID

Wall t

Height H

Outer dia. OD (blank = ID+2t)

End clearance to OD face (transverse, 15–20)

Top/bottom edge (longitudinal, 10–30)

Actual columns N (longitudinal)

cols

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Plate heatercolumns along length

Length A

Width B

Thickness t

End clearance (20–50)

Actual columns N

cols

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Cylinder: OD=ID+2×wall, winding dia.=ID, layout on stretched length L=(S/d)·L_N. Method 1: turns from circumference π×ID, pitch from height/lead gap. Method 2: usable height=H−2×edge(10–30mm), N=stretched/usable (editable), stretched length split into N parts (axial part=stretched/N), actual column length=N×usable, actual stretch factor=column/close-wound. Each column is a vertical straight wire (no coil), direction perpendicular to the circumference, N columns equally spaced around the circle. Half-circle π(D²−d²)/(8S) and plate A·B/S check capacity by area/pitch.

Calculation steps (KANTHAL manual · direct method)

Diameter vs surface load (current P / U / temp)

Curve from the diameter formula: at fixed power/voltage, a higher target surface load gives a smaller diameter. The dot marks the current case.

Diameter formula source: KANTHAL "A Resistance Materials Handbook" p.52 "Design of Wire Elements · Direct calculation method", d = (1/2.91)·³√(I²·ρ·Ct/ps), metric k_d=2.91, d in mm. Length: R₂₀ = U²/(P·C_t), R′ = 4ρ/(πd²), l = R₂₀/R′ (p.53).