# Simple calculation formulas of coil inductance

Formulas and numerical methods of calculation of inductance coils, which uses Coil32, you can look in the help section of the site, namely:

- One turn loop inductance
- Single-layer RF air core coil inductance with close winding
- One-layer helical solenoid with gap between turns
- Non-circular coil with winding pitch
- Multilayer air core coil inductance
- Coil inductance on a ferrite ring core
- Coil in the pot core
- Coil inductance on PCB with spiral square form of turns
- Coil inductance on PCB with spiral round form of turns
- Inductor as a single straight conductor on PCB

Here are the simple handbook formulas for the calculation of inductances, which Coil32 does not use, but which can be useful for electronics hobbyists and students.

Inductance | Formula | |
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Straight conductor | ||

Parallel conductors (current in one direction)r≪w |
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Parallel conductors (current in opposite directions)r≪w |
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Microstrip line | ||

Coaxial line | ||

Single-layer coil(l > 0.8 R) Wheeler's formula(online calculator) |
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Multilayer coil(l ≈ w) Wheeler's formula(online calculator) |
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Flat coil Wheeler's formula (online calculator) |
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Conical coil Wheeler's formula (online calculator) |
L _{H}-inductance of equivalent cylindrical coilL _{P}-inductance of equivalent flat coil |

*In all equations all dimensions are in meters, inductance in Henry. *