Age Verification 21+ Only

The products on this website are intended for adults only. By selecting YES, you certify that you are at least 21 years old and of legal smoking age.

Skip to content
WARNING: This product contains nicotine. Nicotine is an addictive chemical.
WARNING: This product contains nicotine. Nicotine is an addictive chemical.
Enter The Vape Casino Today - Click Here
Enter The Vape Casino Today - Click Here
Tutorial: Ohms Law and Vape Safety Calculator

Tutorial: Ohms Law and Vape Safety Calculator

Overview of Ohms Law Calculator and Vape Safety

Mechanical mods, high wattage regulated mods, rebuild-able dripping atomizers and rebuild-able tank atomizers are becoming extremely popular. Most experienced vapers quickly realize the cost savings of rebuilding and make simple RDA's / RBA's and RTA's part of their daily life. It's no surprise - for the cost of a pack of coils you could buy a year supply of kanthal wire and organic cotton - the building blocks of most vape coils built today. Additionally, self build coils in RDA's tend to produce a lot more vapor and superb flavor over traditional coils, but this post is not about that.

This post is about vaping safely and what that means. And of course out free vape calculator. Let's face it, a metal tube with a high voltage battery or a high wattage (think 150W) box mod with two is nothing to smirk at. You are putting that thing right next to your eyes, mouth and face and firing (activating) it. You WANT to be safe! Before building your first coil, it is highly recommended to buy an ohms meter. This is a device that will tell you the resistance of the coils on your atomizer. Armed with resistance (Ω) you will be able to easily figure out if your setup is safe. But first, what exactly is "safety" when it comes to mods and e-cigs? Easy, the batteries used today for most mechanical and box mods are either 18650 or 20700 series batteries. These batteries vary in Amps - amps are batteries' ability to discharge stored energy (current). When a battery is pushed above its limits, the battery can vent, which means hot chemicals exit the battery under very high pressure or the battery could blow up. Yep. It's as scary as it sounds. That's why you should never push a battery beyond its capability. You should always check the resistance of your coil and calculate the amps the coil will pull from the battery, using either the volts for mechanical mods (4.2 for most 18650 and 26650 batteries) or watts you will set your box mod to. Sub-Ohming is easy and can be done safely, as long as you follow the simple guidelines above. For those of us not in favor of doing the math on our own and converting ohms to watts in your head, we built a handy Ohm's Law Calculator in our signature easy to understand style. Notice, each variable is color coded to represent a piece on the mod below.

Vape Ohm's Law Calculator

To use the Ohms Law Calculator to ensure vape safety, enter any two variables in their respective boxes and hit calculate. If the AMPS value comes out higher than what your battery is rated for, adjust either Ohms on your coil build or wattage output on your box mod. Be sure to check out vape ohms chart in our Variable Voltage and Vaping Power Chart Tutorial.

Enter any two variables

Vape Ohms Icon
Vape Amps Icon
Vape Watts Icon
Vape Volts Icon
Vape Arrow Icon

For the mathematically and scientifically gifted out there, Ohm's Law defines the relationship between power, voltage, current, and resistance. The various possible formulas for Ohm's law are as follows. But if you are feeling lazy you can always default to our vape coil calculator for quick and easy number crunching.

Vape Ohms Law Chart Calculator


NEW: Suorin
NEW: Starbuzz Carbine Hookah

Recommended Links:

Lem'nBerry E-Juice

Our recommended vape batteries for your Vape Devices: Efest IMR 18650 LiMn 3000 mAh Battery Purple and Sony VTC6 18650 3000 mAh Battery 

Vape Tutorials and Guides

Previous article Mechanical MODs Infographics


Ally - December 9, 2021

Tori, I have had the DRAG 2 mod with a different tank and my issue was that my coil wasn’t fully connected to the tank it was in, so the mod wouldn’t recognize it. With the DRAG 3, you can change the mode it’s in, and that might be the issue. Try using SMART or RBA mode and see if that works.
Hope this helps!

Tori - December 9, 2021

Hi everyone! I’ve just bought an Aspire Prestige RTA tank and I am using it with a Voopoo Drag3 mod. I’ve just built the coil up and its working nicely, however for some reason my Mod will not go above 28w since I added the new RTA tank. The coil is around 0.55ohm and the batteries are 3.7v. The problem is its spitting out a little bit of e-liquid due to the low wattage. I need to use a much higher wattage to get some better clouds and flavour. At the moment I’m not getting very much vape out of it. Has anyone got any ideas as to how I can make the wattage higher on the Voopoo Drag3 mod in a safe way please? Cheers!

Matt - September 21, 2021

Im using a .34ohm at 70w

Sebastian - September 21, 2021

Hello everyone commenting, to see if your battery is safe just look the battery worksheet up and check the max current discharge, if ur current is lower than the max discharge rate, you should be fine! Cheers Sebastian.

Timothy r - September 21, 2021

Very useful!

Frankie Emilione - September 21, 2021

Thank you for that calculation chart

Robert - September 21, 2021

So I’ve built the second rda and it seems to be running great with this site is like to be running my mod at 60 but ill take 43 for the right flavor

Chriss - September 21, 2021

For anyone who still confused.

Let’s say you using a battery with 20A.

For electrical mod, just focusing on the total ohms resistance on the calculator, and power, and amp result, no need to worry of the voltages, because the voltages adjusted automatically by your device. My safe ohm is 0.15, with 50W power, amp result is 18A. I don’t like using power over 50W.

For mechanical mod, or electrical mod in “Bypass” mode, pay attention to ohm and voltage, and amp result, for me the save ohm is 0.23, 4.2V, Amp 18A.

The most important thing is always using authentic battery from big brand, Sony, Samsung, LG.
Stay away from that fancy look “vape battery”, because mostly they’re re-wrapped from LG or Samsung battery, and we don’t know exactly what the battery spec is.

Reggy gagabi - September 21, 2021

I have tesla nano 120W is it ok the resistant is .13 and the voltage is 3.26 im using 78W and tiger coil 5loops. Thanks

Steve - November 4, 2018

I have a coil art mage mech tricker with dual coils at 0.1 ohm with a sony vc6. In my reg mod I use dual coils at 0.12 ohm at 112 watts gives perfect flavour with my juice. Would I be able to use the 0.12 ohm coils in my mech safely I want to lower the output to increase the flavour I’m assuming that would give 114 watts through the mech at average current of 3.7 volts am I correct in my thinking

Leave a comment

Comments must be approved before appearing

* Required fields