Mining Investment Calculators and their inconsistencies.

I'm in the process of investing into an S9.
So I've spent the last couple days trying to figure out if it is worth it.

So, I used 2 calculators to estimate my revenue.

However, I've come across some heavy inconsistencies, that don't paint a good picture about the functionality of these simulations.

1. TP's Bitcoin Calculator.
   

• The calculation @ 2000 USD/XBT had some contradicting results. [Link]
  

Supposedly I should break even after 206 days.

However, the 'Net profit in Investment Period' shows only 1380 USD generated. That's calculating with 255 days, and a 1900 USD initial investment. Basic math tells me that I would not break even during that 255 days period, yet the calculator shows 206 days...

So I'm guessing the creator of the calculator doesn't know what NET PROFIT means. NET PROFIT should already include electricity costs, but it does not for some reason.

1. Whattomine
   

• Here we see 11.34 USD for daily profit. Yet back on the other calculator that same value is 26 USD, excluding the electricity costs I assume. And I guess Whattomine accounts for pool fees, whereas the other does not.

Still, the difference is massive.
Aren't these calcuators supposed to use the same variables and similar algorithms to roughly estimate revenue?
Why is there such a difference between results?
How can one create a good enough investment calculation when there are such differing results?

I'm trying to put together an investment analysis, but it is quite difficult with these inconsistencies, and large differences between calculators.

Maybe I'm missing something. Please let me know if I am, and point me towards a reliable calculator/source. Thanks.

Submitted September 02, 2017 at 10:00PM by terasia http://bit.ly/2vTtRhw