Formula Construction

I need help creating a formula to perform the following.

Let position 1 = A
Let position size 1 = AX
Let position 2 = B
Let position size 2 = BX
Let old stop loss = C
Let new stop loss = D

I opened a long position (AX) in GBPUSD at 1.5260 (A) with a stop loss at 1.51460 (C) with a risk of 5%. At the time I write this GBPUSD is pretty much where I opened, but earlier was down 20 pips and also at that time my stop loss had moved up to 1.5164 (D) which decreased my risk from 5% to something less.

What I want to do is open an additional long position (BX) so that I increase my risk back to 5% based off the current price (B) and the new stop loss (D) when combined with my current open position.

Any ideas on a formula?

I need to make this clearer I think so let me be specific...

Lets assume 10000 account size. According to forexcalc.com my lot size would be .45 based on a 110 pip SL. (no, i dont know the formula for this either )

So assume entry of .45 lots at 1.5260.

Later the price dropped to 1.5245 and the indicator I use for SL position moved up to 1.5164 or an 81 pip SL, making my original entry a 3.68% risk leaving me with 1.32%.

According to forexcalc.com that would equal .16 lots.

This would make my average entry 1.5255016 with a 91 pip SL. Per forexcalc.com a 5% risk with that size SL comes out to .54 lots, not the .61...

Im so confused.

I can help with part of this,

10000$ X 5% = 500$

500$ / 110SL = 4.54$ per pip

as 1 lot = 10$ then 4.5$ = 0.45 of a lot.

hope that helps a bit.

Steve.

I'm not confused at all.

You should be able to calculate alone your position size!

C = your capital
R = your risk per trade (in your case 5)
S = your stoploss in pips, i.e. the difference between your open price and stop loss price

Lot size = R / (C * S * 10)

PS. Good example above, we posted in the same time.