Hello, i created this bitcoin profit calculator because most other calculators seems to be inaccurate or just calculating wrong. I've already seen some recalucalting difficulty every 4 weeks, wtf? If you find bugs, wanna suggest features, submit more hardware specifications, tell me how awesome i am or just tell me i should take a shower, feel free to pm user Evolyn (me) on bitcointalk.org forum.

This calculator is still very basic, doesn't look very fancy and is missing alot of features, but they'll come soon.
Current version 2.4, Last update 08.12.2013

to use all features (currently you'll only miss autofill hardware datas), you have to turn on javascript, but well, basics will work without js :)

Hardware
autofill hardwaredata	none
*1 price calculated from usd/btc-ratio *2 price unknown *3 power consumption unknown *4 hashrate unknown
Hashrate (GH/s)
Power consumption (W)
Costs of device (USD)
Delivery time (days)
Network
Current blockheight *
All needed networkdata (e.g. blockreward, next difficulty adjust, etc) will be calculated from blockheight
Difficulty
Difficulty *
Next estimated Difficulty *: 47150109358.96 (-0.92%)
in-/decrease % exponential linear degressive progressive each jump for the next months
- exponential will increase difficulty at same percent every jump (default, just select this if you dont know what to) - linear will increase difficulty at same value every jump - degressive will decrease the jump by half of itself every time (e.g. 25% will become 25%-25%/2=~21,9% next jump) - progressive same as degressive just other direction (this makes no sense, addes just for fun)
Miscellaneous
USD/BTC
USD/BTC in-/decrease per month (%)
Electricity costs (USD/kWh)
Time to calculate (days)
show calculations	daily weekly monthly
calculate reset insert current dif. and blockheight *
* default values are fetched from blockexplorer.com and cached up to 60 minutes unless cloudflare banns this host again :s

changelog
2.4:
- break-even point instead roi (people, me too, tend to mix up these two)
- shows BEP in USD and BTC when reached (honestly, only BEP in BTC is important, simply buy 'n hold bitcoin will outperform your mining unless you reach BEP in BTC)
- updated few hardwaredatas and created db for hardwaredata
2.3:
- added different options how future difficultyjumps are calculated

features comming soon
- autofetch current networkdata (difficulty, block height)
- autofetch fiat/btc ratio
- charts (due to rework of whole code removed for the moment)
- more/better charts
- selectable time to calculate (210 days atm)
- show when roi/max profit/least loss reached
- more hardwaredata
- fiat/btc ratio in-/decrease over time
- "expert" difficulty adjust settings
- estimated next difficulty change
- more infos (e.g. comparison to buy 'n hold)
- more fancy form
- switch usd/euro
- integrate block height for reward halving (still alot of time for this ^.^)
- hardware delivery time
- support for other coins
- dif max 2^256
- reworked "engine"

Disclaimer:
This calculator is free and you can use it at your own risk, as you understand there is no warranty of any kind.