I've been playing around with a few metrics to try to determine how to value LTC versus BTC; these are:

1. Return in USD per day per USD invested

2. Cost of electricity to produce 1 USD

Let's start with 1.

**BTC**: KnC 275 GH/s @ $3,000

$200.00 per coin

0.3485 coins/day at difficulty 391m

or 69.70 USD/day after electicity (300 watts), 1.5% fee, 0.15 cents/kWh

**0.0232333 USD day ^-1 USD invested^-1****LTC**: 40x 7950 (+PSU/mobo/memory/HDD valued at $4000) @ $12,000

$2.40 per coin

23.8434 coins/day at difficulty 1080

or $27.632 USD/day after electicity (9600 watts), 1.5% fee, 0.15 cents/kWh

**0.002302666 USD day^-1 USD invested^-1**How does this look if we chart it out, with BTC difficulty inflating at a rate of 25% every two weeks and LTC difficulty inflating at a rate of 2% every two weeks, given constant prices for both currencies?

Well, that's pretty interesting. In order to hit the same USD return per day per investment dollar, BTC difficulty needs to increase at the same rate (25% per two weeks) for 22 weeks, or almost half a year.

How about 2, cost of electricity to produce 1 USD for both currencies?

With BTC at $200 USD and LTC at $2.40 USD, the equivalent of 1 USD is 0.005 BTC and 0.41666 LTC respectively.

How much power is used to produce this 1 USD? The calculations should be pretty straightforward, so I won't detail them here, but you should be able to plug this into allchains.info and see it for yourself.

BTC

KnC Saturn @ 275 GH/s, 300 W at the wall, 1.5% pool fee, difficulty 391M

0.0154949785 cents per USD

LTC

7970 @ 630 KH/s, 225 W at the wall (my own measurements from one of my rigs), 1.5% pool fee, difficulty 1080

0.5887987788 cents per USD

That's a

**40 fold greater cost of electricity to produce 1 USD in LTC as compared to BTC!** Of course, over time and progressive difficulty increases this will continued to come down, but unless there are massive price swings in the near future or ultra efficient LTC FPGAs/ASICs come out, the cost of production of 1 USD with Litecoin will continue to be many fold that of Bitcoin.

Finally, it's worth mentioning that LTC block reward will undergo halving in less than 2 years time, while Bitcoin is looking at 3.5 years from the current date.

Feel free to point out any stupid oversights or assumptions, but these have been my thoughts over the past week or so, especially as BTC price continues to rise.