SHA256 Mining for a beginner... Worth investing in? How to calculate?

[swarley]

Hey all,

So I am looking to get in to mining...
A little late to the party...

One of my buddies started. Invested a little over 2 grand and racked up 1 BTC in about a month.
This is going to decline steadily and quickly from what I have read.

I understand difficulty goes up over time, and that seems to make it very difficult to actually calculate a ROI.

I was looking at SHA256 profitability on CoinWarz.

Oh, a preface... My rent includes electricity. So no matter how high, my rent doesn't change.

Now if I purchased a SHA256 ASIC, lets say a comprable price with the Antminer S3+ 453 GH/s, $630 (ASIC, Pi, & PSU) and a 2% pool fee
TEKcoin: 96.65 days to break even, 68.24 for 1 BTC
BTC: 185.44 days to break even, 130.94 for 1 BTC.
So let's say I went with TEKcoins,
and got a 1 TH/s ASIC ($1000)
I'd be looking at 69 days to break even, 30.91 for 1 BTC.

What am I missing here? What am I not considering/do I not know about?
Is it difficulty that this calc lacks?
I feel like there is a logical flaw in all of this that I do not have the knowledge to know, but there is one present.
I am looking for a ROI. Not necessarily a HUGE one, but nice money on the side.

Thanks! Sorry if this is confusing/makes no sense...
It makes sense to my novice mind.

*edited to remove altcoin questions*

[philipma1957]

well here is a better calculator

https://bitcoinwisdom.com/bitcoin/calculator


Now for me I can get a pair of  s-3's for  1.16 btc
your tekcoin issue is simple  right now it is a better deal then btc but the tekcoin  diff growth will explode if it is much better for profit then btc.
auto programs will divert hash power from btc to tekcoins

15% growth



10 %  growth

[jonnybravo0311]

Oh, a preface... My rent includes electricity. So no matter how high, my rent doesn't change.

I'm pretty sure your landlord will come knocking on your door if suddenly your electricity usage costs him a few hundred extra dollars a month.

I was looking at SHA256 profitability on CoinWarz.

The problem with coinwarz is that it only gives you an instant snapshot of profitability in that moment in time.  It's great to see what coin might be worth pointing some hash to right now, but it does not offer you any insight into the future.  As philipma1957 pointed out, bitcoinwisdom provides a bit more information and can give you a better picture of your chances at making a positive ROI.  It isn't perfect (for example, you can only assume a static difficulty increase percentage, and you can't factor in potential changes in BTC->fiat ratios), but it's a pretty good way to estimate things.