Edna,
That is a handy calculator, but it doesn't use the correct calculations for a Variable Wattage or Temp Control mod. Ohm's law must be calculated for both sides of the chip inside your mod. (The calculator works fine for a mechanical mod)
The simplest way to figure it is: Wattage / Low battery cut off voltage * 1.1 (add 10% for the inefficiency of the board) = Total Amp Draw
So if you have a mod (with any ohm coil that it will fire with) and it is set to 60 watts and has a single battery it will pull 18.86 amps because:
60/3.5*1.1=18.87
Most mods cut off around 3.5 Volts. With a board inside them amplifying the voltage to you atomizer the lower your batteries voltage, the more demand it is asking from the battery. On the example above, the board it having to amplify the batteries 4.2 Volts (at full charge) to 5.4 Volts at the atomizer to deliver 60 watts. This requires 15.71 Amps to boost the voltage when the battery is fully charged. When your battery is low (3.5 V) it requires 18.86 Amps.
Here is a link to the handiest calculator on the web, but it can be a bit complicated:
Steam Engine - Coil Wrapping
Steam Engine - Battery Draw - to use this make sure to check the "regulated" check box and "power regulation" check box.
I always recommend for beginners to use a pretty good Variable Wattage mod for building. It is just another level of safety. If the mod senses it is shorted, it won't fire, and if the battery gets too low it won't fire. You can still over tax the battery inside it, but it is much harder to do.
Have fun with it, building your own coils can be very satisfying. It not only lets you tailor the coil to your vape, but it is also much less expensive once you have your tools/supplies. I rewick my coils every 3 days or so. This gives me a "new coil" vape for pennies.