Ohmica

Ohmica — The Electronics Calculator Your Multimeter Doesn't Have

Most electronics calculators give you a result.

Ohmica shows the result, the formula behind it, the values substituted into it, and the assumptions used.

Because when you're working on a real circuit, seeing the math matters.

Built for Arduino, ESP32, Raspberry Pi, makers, technicians, electronics hobbyists, and engineers, Ohmica helps you solve real-world electronics calculations quickly and confidently.

WHY OHMICA

• Shows the actual formula used for every calculation
• Supports engineering notation such as 4k7, 100nF, and 20mA
• Works completely offline
• No account required
• No ads
• Available in English and Vietnamese

Unlike generic calculators, Ohmica lets you verify the model behind the result.

For example, when calculating voltage drop, Ohmica can show:

Vdrop = 500 mA × 847 mΩ
(AWG 14, Copper, 40 m Total Run)

You can immediately see what assumptions were used. If a result doesn't match your expectation, you'll know whether the calculation is wrong or your assumptions need adjustment.

CORE CALCULATORS

Fundamentals

• Ohm's Law
• LED Resistor
• Voltage Divider
• Resistor Color Code

Passive Components

• Series / Parallel Resistance
• Series / Parallel Capacitance
• RC Time Constant
• Capacitor Code

Power & Wiring

• AWG Reference
• Voltage Drop
• Battery Runtime
• PCB Trace Width

Signal & Timing

• PWM & Frequency
• I²C Pull-up Resistor

Every calculator is designed for practical electronics work rather than classroom exercises.

Whether you're designing an ESP32 project, sizing LED resistors, checking wire voltage drop, calculating RC timing, or selecting PCB trace widths, Ohmica helps you get answers without opening a browser or doing calculations by hand.

HISTORY & FAVORITES

• Save calculations for later
• Restore previous inputs instantly
• Search tools quickly
• Keep frequently used calculators within easy reach

OHMICA PRO

Unlock advanced professional tools with a one-time purchase.

Pro includes:

• Logic Levels
• Voltage Regulator
• Power Budget
• Pull-down Resistor
• Export History
• Future Pro calculators

No subscription.
No recurring fees.
Pay once, use forever.

If Ohmica saves you time on the bench, Ohmica Pro helps support continued development while keeping the app independent and ad-free.

The calculator your multimeter doesn't have.