Please enter all required numeric values.
RESULTS
Input Parameters Specification
Wire Diameter dRound conductor diameter used for straight wire self inductance calculation.
Wire Length lTotal physical length of the single straight conductor.
Unit SelectionChoose mm, cm, um, inch, or mil for quick RF wire inductance conversion.
OutputSelf inductance result in nH for circuit parasitic inductance estimation.
Practical Operational Examples
RF Lead Inductance
Estimate straight conductor inductance for component leads, jumpers, and RF wiring.
PCB Prototype Wire
Change conductor diameter and length to compare parasitic inductance in high-speed layouts.
Diagrams & Theory
Wire self inductance depends mainly on conductor length and wire diameter. Longer conductors increase inductance, while thicker conductors reduce it.
Formulas & Mathematical Logic
Step 1: Convert wire diameter d and wire length l using the selected unit multipliers.
Step 2: x = d / (2 × l)
Step 3: L = 2 × l × [ ln((2 × l / d) × (1 + sqrt(1 + x²))) - sqrt(1 + x²) + 0.25 + x ]
Step 4: Display L in nH with 3 decimal places, preserving the original JavaScript calculation logic.
Step-by-Step Example
Example: wire diameter d = 1 mm and wire length l = 5 cm.
The calculator converts diameter and length using the selected unit multipliers.
Then x = d / (2 × l) is calculated.
The straight-wire self inductance expression is applied using the converted dimensions.
The result is displayed in nanohenries, which is useful for RF and high-speed circuit work.
How to Use This Calculator
Enter the round wire diameter.
Select the diameter unit: mm, cm, um, inch, or mil.
Enter the physical wire length.
Select the length unit.
Click Calculate to get the estimated self inductance in nH.
About This Calculator
Estimate parasitic inductance of a straight round wire.
The CalcBoy Wire Self Inductance Calculator helps estimate how much inductance is added by a single straight conductor, jumper, lead, or prototype wire.
Straight wire inductance is easy to ignore, but it can become important in RF circuits, fast switching power supplies, gate-drive loops, pulse circuits, and high-current wiring. Even a short jumper can add enough parasitic inductance to create ringing, voltage overshoot, slower edge transitions, or measurement errors. This calculator gives a quick estimate using wire length and conductor diameter.
The main design lesson is simple: longer wire increases inductance, and thicker wire changes the result slightly through the diameter term. In most practical layouts, reducing wire length and keeping the return path close is more effective than only increasing conductor diameter. Use this calculator for early checks, then verify critical circuits with measurement when very fast edges or RF performance matter.
Best UseComponent leads, jumper wires, RF prototypes, pulse wiring, and quick parasitic checks.
Length EffectLonger wires usually add more self inductance.
Diameter EffectThicker conductors slightly reduce the calculated value for the same length.
Design ReminderReal circuits also depend on return path, bends, solder pads, and nearby conductors.
Tip: In MOSFET gate loops, RF jumpers, and pulsed-current paths, shaving a few millimeters from lead length can reduce ringing more than expected.
Frequently Asked Questions
What is wire self inductance?
Wire self inductance is the inductance of a single conductor caused by magnetic energy stored around the wire when current flows through it.
Why does wire length matter so much?
A longer wire creates a larger magnetic field path, so the estimated inductance generally increases with length.
Does thicker wire reduce inductance?
For the same length, a larger wire diameter usually reduces the calculated self inductance slightly.
Can I use this for PCB traces?
This calculator is for round wire. PCB traces have flat geometry, copper thickness, and reference-plane effects, so a PCB trace calculator is better.
Why is the result in nH?
Short conductor inductance is usually very small, so nanohenries are more practical than henries.
Is this useful for RF circuits?
Yes. At high frequency, even small nH values can create noticeable reactance and affect tuning, matching, or signal integrity.
Does this include return-path inductance?
No. It estimates straight wire self inductance only. A full circuit loop also depends on the return conductor and layout geometry.
Related Calculators
Wire Loop Inductance CalculatorEstimate inductance of a circular wire loop.
Wire Over Plane Inductance CalculatorCalculate wire inductance above a reference plane.
Parallel Wire Inductance CalculatorEstimate inductance of two parallel conductors.
Inductance Reactance CalculatorConvert inductance into reactance at frequency.