Break-Even Price
The MLRT price at which the value of coins you mine in a day exactly equals the cost of the electricity you spent producing them.
Break-even price is the clean floor in any honest profitability calculation. It is your daily power cost divided by the MLRT you produce per day at current network conditions. If the market price of MLRT is above this number, you are net-positive on electricity for that day. If it is below, you are subsidising the network from your wallet, which is a valid choice but worth doing on purpose rather than by accident. Break-even price does not include hardware depreciation or your time, so it is a floor, not a profit figure.