# Converters & Calculators

## Use the below converter to convert mils to: mm, Oz, um, inch.

## Use below to calculate any control impedance conductor (if you don't see it just refresh the page):

## Use below calculator to calculate trace width , and via diameter according to requested current:

This Javascript web calculator calculates the resistance, voltage drop, and power loss of printed circuit board vias.

**Inputs:
**

Finished Hole Dia | ||

Plating Thickness | ||

Via Length |

**Optional Inputs:
**

Applied Current | Amps | |

Plating Resistivity | Ohm-cm |

**Electrical Results:
**

Resistance | Ohms | |

Voltage Drop | Volts | |

Power Loss | Watts | |

Estimated Ampacity | Amps |

**Thermal Results:
**

Thermal Resistance | Deg. C/Watt |

**Notes:
**Resistance = Resistivity*Length/Area

Area = pi*(Inner_dia + Plating_thk)*Plating_thk

Resistivity = 1.9E-6 Ohm-cm (plated copper)

(plated copper is much more resistive than pure copper)

Copper Thermal_Resistivity = 0.249 cm-K/W (at 300K)

Est_Ampacity [Amps] = k*(Temp_Rise [deg C])^b*(Area [mils^2])^c

For IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725

Disclaimer:

These calculations are believed to be correct, but not guaranteed. Use at your own risk!

This Javascript web calculator calculates the trace width for printed circuit boards based on a curve fit to IPC-2221 (formerly IPC-D-275).

**Inputs:
**

Current | Amps | |

Thickness |

**Optional Inputs:
**

Temperature Rise | Deg | |

Ambient Temperature | Deg | |

Trace Length |

**Results for Internal Layers:
**

Required Trace Width | ||

Resistance | Ohms | |

Voltage Drop | Volts | |

Power Loss | Watts |

**Results for **External Layers in Air:

Required Trace Width | ||

Resistance | Ohms | |

Voltage Drop | Volts | |

Power Loss | Watts |

**Notes:**

The trace width is calculated as follows:

First, the Area is calculated:

Area[mils^2] = (Current[Amps]/(k*(Temp_Rise[deg. C])^b))^(1/c)

Then, the Width is calculated:

Width[mils] = Area[mils^2]/(Thickness[oz]*1.378[mils/oz])

For IPC-2221 internal layers: k = 0.024, b = 0.44, c = 0.725

For IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725

where k, b, and c are constants resulting from curve fitting to the IPC-2221 curves

**For geometry diagrams, click on the pictures below.**

Disclaimer:

These calculations are believed to be correct, but not guaranteed. Use at your own risk!

Zeev Jabotinsky St,

Bursa, Ramat-Gan, Israel