This guide follows on from Part 8 of my step by step guide to building a 6 GPU Mining rig. In this part I’m going to look at calculating your profit and ROI. You should now be mining 24/7 with 180-190 Mh/s on Ethereum or 4.5-5Kh/s on Monero. These two coins and other coins that use the same block chains are generally the most profitable right now for ATI card mining rigs.
Return on Investment ROI
Now the hard part of building your rig is over, you need to make sure you maximize your profit to get the rig paid for ASAP. Once you have made enough money after electric costs to pay for your rig, everything else from then onward is profit.
You should have kept a detailed record of the total build cost of your rig. If you have been following my guide your rig should have cost you in the region of £2,200 / €2,500 including all the extras. In the US you can probably pick everything up for around $2,000- $2,250 because prices are generally cheaper then the UK/EU.
This cost is important to calculate your ROI.
Switch to the Cheapest Electric Provider
Unless you are lucky enough to have free power the next thing to do is find out how much your electricity cost is per kw/h. Once you have this information you can now search for a better deal. In the UK electric tariff’s have two elements a “standing charge” and a “usage charge”. A standing charge is just a fixed rate you pay every day no matter how much electricity you use. A usage charge is an amount you are charged per kw/h, which is therefore directly proportional to your usage.
Generally the higher the standing charge (or fixed part of your bill) the lower your usage charge. For almost all miners you want the cheapest usage charge you can find. This will probably have one of the highest standing charges, but that doesn’t matter because you are going to be using a lot more power than a normal residential user.
In the UK you should be aiming for under £0.12 per kw/h which as of December 2017 is still available from some providers. The rest of Europe prices range widely from country to country due to local taxes, but expect to pay anywhere between €.10 to €.30 euros per kw/h. The US is cheaper at around $0.10 to $0.12 per kw/h.
My cost is currently 11.44p per kw/h fixed until next summer.
Measuring your Power
Now you know how much you pay per kw/h your next job is to find out how much your rig is drawing at the wall. For this you will need some kind of wall power monitor. As discussed in my previous guide I use a TP-Link HS110 Wi-Fi Smart Plug which provides the data directly to your phone.
The advantage of this plug is that it monitors your power 24/7 and provides you with a 30 day running total. This is very handy to check at the end of each month, so you know exactly how much power your rig has used. My rig uses 930W at the wall mining ethereum and 780W using the cryptonight algorithm.
This means that after 24 hours of continuous use my rig will have used:-
- 0.93w x 24 = 22.32 kw/h mining Ethereum.
- 0.78w x 24 = 18.72 kw/h mining Monero.
Now we can multiply the daily kw/h rate by your usage charge to get your daily cost:-
- 22.32 x £0.1144 kw/h = £2.55 a day mining Ethereum.
- 18.72 x £0.1144 kw/h = £2.14 a day mining Monero.
If you are in the US, or Europe, just plug your own figures into the above to get your daily electric costs.
Calculating your Profit
If you are using Nicehash and mining to a Nicehash wallet (which you should be) you should be making the minimum payment threshold every day. It is therefore easy to see how much you have actually earnt after Nicehash fees each day.
If you want you can then transfer to an external wallet at the end of each month which provides you with a nice easy way to see exactly how much you have earnt that month after all costs and transfer fees.
At the time of writing the Cryptonight algorithm is currently the best for ATI rigs and for the last 30 days I’ve average £12 a day for my 6 x RX 580 GPU mining rig.
I can work out my profit as follows (converted into dollars and euros based on my costs):-
- £360, less electric costs £64 = £296 profit
- €400, less electric costs €70 = €320 profit
- $485, less electric costs $85 = $400 profit.
Calculating your ROI
Your ROI is now pretty easy to calculate, you just take the cost of your mining rig and divide it by your monthly profit. Taking the above examples and applying to our original build cost we get:-
- £2,200 / £296 = 7.4 months
- €2,500 / €320 = 7.8 months
- $2,000 / $400 = 5 months
Note that three months ago the ROI was a lot longer, typically 10 to 12 months, but the recent rise in bitcoin prices and the increase in cryptonight algorithm has reduced the ROI significantly for ATI rigs.
Now the above assumes that every month you sell your bitcoin, pay your power costs and bank the rest in your local currency. This is perfectly fine and is the lowest risk method to get your investment back, but it is by no means the quickest.
By taking a little more risk and holding onto your mined coins you can gain a lot more (but also risk losing more!).
My Profit in 3 months
Below are my actual earnings and electric costs from the rig in this guide since I started in September 2017:-
- September 2017 – BTC 0.0522681 – Electric costs £72.5
- October 2017 – BTC 0.04707751 – Electric costs £69.5
- November 2017 – BTC 0.0567512 – Electric costs £64
Now if I had converted to £ at the end of each month my profit after electric would have been something like this:-
- September 2017 – £96
- October 2017 – £155
- November 2017 – £352
Total profit £603 / €663 / $814
However, instead I’ve kept all the bitcoin which at today’s price of £8,370 = £1,306, less electric pf £206 =
- Total profit £1,100 / €1,210 / $1,485.
That’s 82% more than I would have earnt if I had cashed in early. If mining profitability continues I should hit my ROI in another 2 to 3 months. When I started only three months ago I had calculated it would take me just over 12 months, yet I’m now looking at 5-6 months total.
That’s why it is important not to rely too much on the ROI calculators. You are of course taking a risk on the price of bitcoin increasing. It can just as easily go the other way too and take longer than your initial calculations.
Once you hit your ROI you can cash in your bitcoin and from then onward everything you mine, less electric will be profit. Plus you still have the second hand value of your rig once you stop or upgrade.