# Shockley Diode Equation Calculator

URL: https://speedycalculator.com/calculators/physics/shockley-diode/
Last updated: 2026-10-30

> The Shockley diode equation calculator finds the current through a p–n junction diode from its forward voltage, saturation current, ideality factor and temperature.

## Inputs

- Diode voltage V_D (V, mV, kV, µV, MV)
- Saturation current I_S (A)
- Ideality factor n
- Temperature (K, °C, °F)

## Results

- Thermal voltage V_T
- Diode current I

## Formula

```
I = I_S·(e^{V_D/(n·V_T)} − 1),  V_T = k·T/q
```

## Explanation

The diode equation describes the exponential current–voltage curve of a p–n junction: almost nothing flows until about 0.6 V for silicon, then current shoots up. Every 60 mV more increases the current roughly tenfold at room temperature.

### How to use the Shockley Diode Equation Calculator

- **Diode voltage V_D**
- **Saturation current I_S (A)**
- **Ideality factor n**
- **Temperature**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Enter the diode voltage, saturation current, ideality factor and temperature.

### Inputs explained

FieldWhat to enterDiode voltage V_DUnits: V, mV, kV, µV, MVSaturation current I_S (A)A numberIdeality factor nA numberTemperatureUnits: K, °C, °F

### What each result means

- **Thermal voltage V_T** = 1.380649e-23×[Temperature]÷1.602176634e-19×1000
- **Diode current I** = [Saturation current I_S (A)]×(exp([Diode voltage V_D]÷([Ideality factor n]×[Thermal voltage V_T]÷1000)) - 1)

### Example values

How the main result changes when **Diode voltage V_D** changes and everything else stays at the example values above:

Diode voltage V_D (V)Diode current I (mA)0.3252.8824e-60.48750.00150.650.83080.8125446.06610.975239,485.43321.369,030,147,778.7115

## Worked example

Inputs — Diode voltage V_D: 0.65 V; Saturation current I_S (A): 1e-14; Ideality factor n: 1; Temperature: 300 K.

Results — Thermal voltage V_T = 25.852 mV; **Diode current I = 0.83084 mA**.

## Key terms

- **Saturation current**: Reverse leakage current of an ideal diode.

## FAQ

**What is the thermal voltage at room temperature?**
About 25.85 mV at 300 K.

**What is the ideality factor?**
1 for an ideal diode, up to 2 with recombination.

**Why is reverse current tiny?**
It is limited to the saturation current, about 10⁻¹⁴ A for silicon.

**Does the equation work at high current?**
Series resistance makes real diodes deviate.


## Sources

- [OpenStax – University Physics Volume 2](https://openstax.org/details/books/university-physics-volume-2)
- [HyperPhysics (Georgia State University)](http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html)
- [NIST – Fundamental physical constants](https://physics.nist.gov/cuu/Constants/)