The more someone wins by discretion, the more sloppy their lot size calculations tend to be problem

Hello,lulu.fx here to introduce myself.

I usually trade discretionary, focusing on GOLD (XAUUSD), and I am a current trader with Fintokei qualification experience.

Today, I will write a somewhat strict piece about the area where discretionary traders tend to deceive themselves the most"lot size calculation".

In short: the usual 0.5 lots are the most dangerous

The more you win by discretion, the more you tend to fall into this routine.

「SL is… well, in the usual position」

「The lot is… well, the usual 0.5」

「Okay, entry」

That used to be me. I still slip back if I’m not careful.

But when you think about it carefully,it’s extremely dangerous.

Because,the position of SL (= pip width) changes, so even with the same 0.5 lot, the risk amount is completely different.

For example:

• 0.5 lot with SL 8 pips: loss 4,000 yen → 0.4% risk on a 1,000,000 account
• 0.5 lot with SL 30 pips: loss 15,000 yen → 1.5% risk on a 1,000,000 account
• 0.5 lot with SL 80 pips: loss 40,000 yen → risk 4.0% on a 1,000,000 account← outside Fintokei disqualification

Even with the same 0.5 lot, the risk can differ by10 times.

In this way, as soon as you draw the line, you automatically evaluate risk to 0.3% and a healthy move. Details later in the article.

Why do discretionary traders end up choosing the "usual lot"?

In my view, there are three reasons.

❶ Calculations are a hassle

To accurately calculate the lot that keeps risk at 1%:

• Account balance
• 1 pip value of the currency pair
• Current rate
• Pips to SL
• Allowed risk%

You need to utilize all of these. Mental math is not enough, and switching to Excel is a pain.

Then it becomes“Well, maybe just use the usual 0.5”.

❷ A memory that “this lot won me in the past”

Humans remember a winning lot as the “correct answer”.「That’s the right approach」. And you want to repeat the same lot.

The problem is that the winning lot in the past was a result of the combination with that SL pips. If the SL pips change, the risk with the same lot is completely different.

❸ The effort to open a lot-calculator equals missed entry opportunities

Discretion traders are eager to enter at the moment when 「now is the only time」. Opening Excel or an online calculator takes about 30 seconds, which creates a sense of missing the entry opportunity.

As a result, they compromise with 「oh well, I’ll use the usual lot」.

From here on, I will share deeper discussion and solutions

If you’ve read this far and think 「I get it, that’s me」, please keep reading the rest.

From here, I will share what I observed on Discord: 「A discretionary trader who was winning for 5 years blew away annual profits in a month due to sloppy lot calculations,」 and the complete features of the MT4 tool I built for myself to prevent that tragedy.This tool allows you to draw three lines for Entry, SL, and TP, and

finish a 30-second lot calculation in 5 seconds. Since I started using it, my habit of entering roughly with the usual lot has completely disappeared.