Ohm law calculator
Current, voltage, resistance: calculations related to Ohm law. Enter known values (e.g. voltage and resistance of conductor) and we'll show you step-by-step how to transform basic formula and find out missing value (e.g. current)

Beta version#

This online calculator is currently under heavy development. It may or it may NOT work correctly.
You CAN try to use it. You CAN even get the proper results.
However, please VERIFY all results on your own, as the level of completion of this item is NOT CONFIRMED.
Feel free to send any ideas and comments !

Symbolic algebra

ⓘ Hint: This calculator supports symbolic math. You can enter numbers, but also symbols like a, b, pi or even whole math expressions such as (a+b)/2. If you still don't sure how to make your life easier using symbolic algebra check out our another page: Symbolic calculations

What do you want to calculate today?#

Choose a scenario that best fits your needs

Calculations data - enter values, that you know here#

Current (I)
Voltage (U)
Resistance (R)

Units normalization#

Voltage (U)Show source230 [V]230\ \left[V\right]
Resistance (R)Show source460 [Ω]460\ \left[\Omega\right]
Current (I)

Result: Current (I)#

Used formulaShow sourceI=URI=\frac{U}{R}
ResultShow source12\frac{1}{2}
Numerical resultShow source0.5 [A]0.5\ \left[A\right]
Result step by step
1Show source230460\frac{230}{460}The original expression-
2Show source230460\frac{\cancel{230}}{\cancel{460}}Cancel terms or fractions
  • Dividing a number by itself gives one, colloquially we say that such numbers "cancel-out": aa=1 \frac{\cancel{a}}{\cancel{a}} = 1
  • to find-out the simplest form of fraction we can divide the numerator and denominator by the greatest common divisor (GCD) of both numbers.
3Show source12\frac{1}{2}ResultYour expression reduced to the simplest form known to us.
Numerical result step by step
1Show source0.50.5The original expression-
2Show source0.50.5ResultYour expression reduced to the simplest form known to us.
Units normalization
Show source0.5 [A]0.5\ \left[A\right]

Some facts#

  • The Ohm's law states that the electric current is directly proportional to the voltage (i.e. the difference of potentials between the ends of the conductor) and inversely proportional to resistance of the conductor.
  • Mathematically, Ohm's law can be written in the following form:
    I=URI = \dfrac{U}{R}
  • For practical reasons, all conductors (and also any electric or electronic elements that may appear in the circuit) are divided into:
    • linear elements - meeting Ohm's law (in given circumstances), which can be called "ohmic",
    • non-linear elements - where Ohm's law doesn't apply (like diodes)
  • It's important to note, that Ohm's law is stated as "for a conductor in given state", meaning that other cirumstances are intentionally ignored.
    For example, the temperature change:
    • if the voltage is increased, then the current will increase (by Ohm's law),
    • this may potentially increase the temperature of the conductor,
    • the resistivity of materials usually changes with temperature, so:
      • if the material is a metal (like copper), then the resistance will increase and so will reduce the current,
      • for some other materials (like germanium), the resistance will decrease and so will further increase the current,
    • in summary: the voltage increase changed indirectly also the resistance - additional factor to consider. It doesn't break the Ohm's law, but introduces additional factor (resistance change when temperature changes).

Tags and links to this website#

What tags this calculator has#


This is permalink. Permalink is the link containing your input data. Just copy it and share your work with friends:

Links to external sites (leaving Calculla?)#

JavaScript failed !
So this is static version of this website.
This website works a lot better in JavaScript enabled browser.
Please enable JavaScript.