The $4,500 Tuesday

It was late 2021. I was working from home, the kids were at school, and I'd just passed three Apex evaluations in my first month of prop trading. I felt like a genius. Three funded accounts, $150K in combined buying power. I was going to retire by 43.

The problem was, I was trading 10 contracts of MNQ on every account. On a $1,500 trailing drawdown. That's roughly $50 of risk per point, per account. One bad morning of NQ selling off 30 points and I was done. Three accounts, gone. Not because my trade idea was wrong — NQ actually reversed and ripped 60 points that afternoon. I just didn't survive long enough to see it.

The uncomfortable truth: I didn't have a strategy problem. I had a math problem. I was risking 33% of my drawdown on a single trade. One loser and I was in the danger zone. Two losers and I was cooked.

The Spreadsheet Phase

After licking my wounds (and explaining to my wife why the "side project" had a setback), I did what any self-respecting software engineer would do: I opened a spreadsheet.

I built a little calculator. Drawdown amount, risk percentage, instrument tick value, stop loss in points. It spat out a contract count. Simple enough for one account.

But I had six accounts. Different firms. Different drawdown types — Apex uses intraday trailing that locks, TopStep uses end-of-day trailing, some firms use static drawdown. The rules are different for each one, and the amount of risk you can take depends on which type you have. My spreadsheet turned into a monster with 14 tabs.

My 14-year-old daughter walked past my desk, looked at the screen, and said: "Dad, you're a way better coder than trader."

She wasn't wrong.

So I Built the Thing

I'm a full-stack developer. I've been writing code since before my kids were born. Building a web tool is faster for me than maintaining a spreadsheet. So one weekend, while the kids were at their mom's soccer tournament, I sat down and built the first version of what would become FundedSizer.

The idea was dead simple: tell me your accounts, tell me your risk tolerance, tell me what you're trading, and I'll tell you exactly how many contracts to put on each account. Not a guess. Not "oh, I usually trade 5 lots." An actual number based on your real drawdown today.

Version one took a weekend. It handled Apex, TopStep, and a couple others. You'd add your accounts, set a risk percentage, pick an instrument and stop loss, and it would distribute contracts proportionally based on each account's available drawdown.

I used it every morning before trading. And something clicked. I stopped blowing accounts.

What It Actually Does

FundedSizer isn't magic. It's just math that I was too lazy (or too proud) to do by hand every morning. Here's what it calculates:

The key insight: Most prop traders don't fail because they can't find good entries. They fail because they don't know how much they're actually risking relative to their drawdown. A 2% risk on a $3,000 static drawdown is very different from 2% on a $1,500 intraday trailing drawdown.

Why It's Free

Because I built it for myself. The tool already existed before anyone else used it. Hosting a static HTML page costs nothing. There's no backend, no database, no accounts to manage, no data to store.

I shared it with a few guys in my trading Discord. They shared it with their groups. People kept asking "what's the catch?" The catch is that some of the prop firm links are affiliate links. If you open a new account through one, I get a small referral. It costs you nothing extra and it keeps the lights on.

That's it. No premium tier. No "pro features behind a paywall." No email capture. No course to sell you. Just a tool that does one thing well.

Better Coder Than Trader

My daughter was right. I'm a better coder than I am a trader. My win rate hovers around 52%. My R-multiple is about 1.3. My edge is small but positive. I'm never going to be one of those guys posting million-dollar funded account screenshots on Twitter.

But I don't blow accounts anymore. And when I sit down to trade at 9:25 AM, I know exactly how many contracts to put on, how much I'm risking, and how many losers I can survive. That knowledge alone has saved me thousands in drawdown resets.

If you're reading this, you probably trade prop firm accounts too. You probably have a strategy you believe in. And you probably don't do the position sizing math as carefully as you should.

That's what this tool is for. It takes 60 seconds. Try it.

Try the thing I built

60 seconds, all your accounts, one answer. It's the tool I use every morning before I trade.

Open the calculator