E-Textile Resistance Calculator

Calculate conductive thread and e-textile trace resistance from material type, thread dimensions, stitch count, wash cycles, and operating temperature.

Inputs

Thread material

Thread/trace length (cm)

Thread diameter (mm)

Number of stitch junctions

Contact resistance per stitch (ohm)

Wash cycles completed

Operating temperature (C)

Tab to move between fields

Results

Total resistance (ohm)

218.4

Thread resistance (ohm)200

Stitch junction resistance (ohm)10

Resistance per cm (ohm/cm)2

Current at 3.3V (mA)15.11

Power at 3.3V (mW)49.86

Wash degradation (%)0

Resistance after 50 washes (ohm)436.8

Safe Current Ma$7.07

Safe Current Calc$15.13

How to Use This Calculator

Select your conductive thread material (silver-coated nylon, stainless steel, carbon, or copper wire).
Enter the total thread length (cm), thread diameter (mm), and number of stitch junctions in the circuit.
Set the contact resistance per stitch (Ω) based on construction quality — typically 0.1–2 Ω.
Enter wash cycles completed and operating temperature (°C) to account for degradation.
Review total resistance (Ω), estimated current at 3.3 V, and power dissipation in the outputs.

How the result changes with Thread diameter (mm)

Thread diameter (mm)	Total resistance (ohm)
0.25	322.27
0.73	45.24
1.32	21.14
1.8	16.18

What each input means

Thread material: Select the thread material
Thread/trace length (cm): Total length of the conductive path in centimeters.
Thread diameter (mm): Diameter of the conductive thread in millimeters.
Number of stitch junctions: Number of stitch connection points adding contact resistance.
Contact resistance per stitch (ohm): Electrical contact resistance at each stitch junction.
Wash cycles completed: Number of machine wash cycles the garment has undergone.
Operating temperature (C): Temperature during use. Body contact is typically 33-37C.

What each result means

Total resistance (ohm): Total end-to-end resistance including thread, stitches, wash degradation, and temperature effects.
Thread resistance (ohm): Resistance from the conductive thread alone (before stitches, wash, temp).
Stitch junction resistance (ohm): Total resistance added by all stitch contact junctions.
Resistance per cm (ohm/cm): Linear resistance per centimeter for this thread diameter.
Current at 3.3V (mA): Current flow when 3.3V (typical wearable supply) is applied.
Power at 3.3V (mW): Power dissipated as heat at 3.3V supply.
Wash degradation (%): Percentage resistance increase due to washing.
Resistance after 50 washes (ohm): Projected resistance after 50 machine wash cycles.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Thread material = 0, Thread/trace length (cm) = 100, Thread diameter (mm) = 0.3, Number of stitch junctions = 20 = 7 input(s) provided
Calculate Total resistance
Total resistance = baseResistance * washFactor * tempFactor
218.4 = 218.4
Calculate Thread resistance
Thread resistance = rPerCm * threadLengthCm
200 = 200
Calculate Stitch junction resistance
Stitch junction resistance = numStitches * stitchContactResistance
10 = 10

Engine last updated July 28, 2026. Checked against 3 independently-derived tests — how we verify calculators.

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