Free Shipping on orders over £40

What is Ohm’s Law?

Ohm’s law comes into play with vaping once you decide to step up from disposable vape kits and starter kits and want to customise your experience. Advancing to using customisable vape kits enables you to discover which coil, wattage and resistance produces the lung hit and cloud size of your liking.

Moving onto advanced vaping with the use of sub-ohm kits and tanks can seem pretty daunting, so we’ve covered the theory to inform your journey. Understanding the fundamentals of Ohm’s law is the first step in altering your vape to suit your personal preferences, and is highly recommended if you want to ensure that you are practicing safe vaping. Especially if you’re advancing to direct-to-lung (DTL) vaping, you’re going to need to understand Ohm’s law as particularly sub-ohm vaping requires additional knowledge.

Not only this, having an understanding of Ohm’s law ensures you have a safe and long-lasting vaping experience. Using this law allows you to avoid overheating the coil and damaging your e-cig to the point where you would have to replace the whole device.

The object of customising your vape using this law is to maximise the power output of the device. More power means better performance, increased warmth and flavour in your e-cigarette. Finding the perfect balance of wattage to resistance can be immensely satisfying for vapers as you achieve your perfect clouds and overall unique vaping experience.

So, what is Ohm's law?

You’ll probably recognise the Ohms law triangle from your high school physics lessons. To avoid bringing up any secondary school trauma, we’re not going to dwell on the physics aspect of Ohm’s law for too long.

You want to understand how Ohms affects your vaping, and understanding the fundamentals of the theory can inform which vape kits you buy and which coils and wattage are best for you.

Ohm’s law details the relationship between voltage (the amount of energy), current (the flow of energy around a circuit) and resistance (how much a material can resist the current flowing through it). The formula for this equation is:

E (voltage) = I (intensity of current) x R (resistance)

The well-known Ohms triangle may help to visualise the equation a little better…

The definition of Ohm’s law is that the electrical current is proportional to voltage and inversely proportional to resistance. This sounds much more confusing than it is, so let’s put it into practice.


Voltage is measured in volts and acts like pressure in an electrical circuit. Voltage is potential difference, or in other word, the pushing force of a circuit. The electrical current of a circuit is directly proportional to the voltage of the batteries, so the higher the voltage, the higher the current. Explore our different vaping batteries to find your perfect push!

The problem is, upping the voltage to get a higher current (and more power) in your vape can be dangerous, as the voltage surpasses safe limits. Under constant resistance, applying a higher voltage would cause the coil to heat up too quickly and overload the circuit, damaging the vape kit.


Current is measured in amperes, or amps (a) for short. The current flows through a conductor in an electrical circuit (ie: wire) and tells us how much power the vape has.

There’s a limit as to how many amps can flow through your vape kit at any one point, so it’s not as simple as increasing the current to get more power. Decreasing resistance is the best way to maximise the impact of your vape.


If you are reading this guide in an effort to increase your understanding of advanced vaping, you will be more than accustomed to coil resistance by now, but for those who are not, the lower the ohms that your coil has, the more intense your vapour production will be.

Resistance is measured in ohms, and has the most impact on your vaping experience. Ohm resistance is inversely proportional to the current, so with a higher resistance coil, the amp reading for the circuit will decrease.

The coil in your vaping device is the resistor of the circuit and responsible for heating the e-liquid. As the resistance of the coil increases, it requires more voltage from the battery to produce the same current throughout the circuit.

For vapers, picking the right resistance coil for your e-cig essentially determines its power output. If your vape batteries are inbuilt, you won’t have much control over voltage. However, this will not be the case if you opt for an external battery unit. Discover our range of coils and find out which can create your perfect vaping experience.

Not the best at physics and don't want to be fussed with Ohms law equations?

It’s not the nineteenth century any more, and we’re sure that George Ohm wouldn’t mind us saving the headache and using an Ohms law calculator to calculate this relationship.

One more thing...

You’re probably thinking, that all sounds great, but most vape kits usually talk about watts, not volts. That’s because watts tell us the amount of push in the circuit, not the power output itself. Wattage is the measurement of power in an electrical device.


The power output (P) of any electric circuit is measured in watts (W) and is simply the voltage of the battery multiplied the current. In a DC circuit, like the one in your vape device,

P (watts) = I (amperes) x V (volts)

Now we haven’t mentioned Ohms here, that’s because wattage and resistance aren’t directly related. Luckily, as electrical current and voltage are proportional, we can apply the same principle that Ohms are inversely proportional to wattage.

So, the lower the ohms, the higher the wattage output.

Here’s a pie chart to demonstrate exactly how the electrical elements voltage, wattage, power and resistance relate to one another.

How Ohms law affects your vape mod

Okay, the physics lesson is over! Vape kits are electrical circuits at the end of the day, so understanding the fundamentals of their electricals helps to nail your vaping experience.

How can you customise your vape to its optimum performance?

1) Reduce the resistance of the coil in your vape

Swapping out your coil for a lower resistance coil is the quickest way to amp up the current in your e-cig. For vapers who want to try sub-ohm vaping, remember: lower ohms + higher wattage = bigger clouds.

Remember to change the coils in your vape every 1-3 weeks to ensure that they are still performing at its optimum level, don’t burn out and ensure the maximum taste from your e-liquids.

2) Go for batteries with a larger voltage

If you’re an advanced vaper or want to upgrade to a fully customisable device, go for an external battery vape to control every aspect of your hit. Having a larger battery in your device will enable you to output a higher wattage at a low resistance.

Thicker e-liquids (High VG e-liquids) are designed for use in e-cigs with larger batteries as the vegetable glycerine: propylene glycol (VG: PG) ratio requires more power to heat up and results in larger clouds.

Kits with high voltage batteries function best with low resistance coils as the lower ohm resistance facilitates quicker heating of the liquid to maximise the power flowing through the circuit.

Understanding Ohm's law can transform your vaping experience

Customising your vaping practice is a process of trial-and-error to find the perfect combination of resistance, power and wattage for you.

Still transitioning from using mouth-to lung tanks to direct-to-lung tanks or wanting to advance your vaping but don’t know where to start? Try our sub-ohm kits to get a taste of what custom vaping feels like.

Ready to go with custom vaping and want to get stuck into different flavours of e-liquid? Find our range of shortfills for your vape device here.

We will be happy to hear your thoughts

Leave a reply

Legion Of Vapers
Register New Account
Reset Password
Shopping cart