lot size formula for cfd and forex based on risk percentage

External question — Quantitative Finance Stack Exchange Author: Valometrics.com Original post: https://quant.stackexchange.com/questions/55841 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I have a question regarding the calculation of the lot size for cfd and forex instruments when we have a risk amount as a percentage of the balance. So how to compute the lot size to trade knowing the stop loss value and the entry point value for a buy trade in order to match the risk amount when the stop loss is reached? Thanks in advance for your answer!