My name is Justas. I'm a trader based in Lithuania. In late 2021 I put a chunk of my savings into a 25x position on an altcoin and didn't properly check where the liquidation price was. By the time I looked, the position was gone. The candle that took it out was a 3.8% wick — normal market noise at that leverage.
That's the short version of how RektCalc started.
The longer version: after that trade I went looking for a liquidation calculator I could trust, and what I found was either behind a paywall, shoved full of ads for the exchanges I was using, or just wrong — they'd show me a number that didn't account for maintenance margin, and they certainly didn't tell me that at 25x I had 3.5% of runway before the exchange force-closed me. I needed something honest.
So I built the liquidation calculator first. Then position sizing, because that's the thing that would have actually saved me — if I'd sized to a 1% account risk, I'd have lost $80 instead of everything in that position. Then a DCA calculator that shows you real break-even rather than "look how much lower your average is now." Then 230 more calculators, because once you start pulling on the thread of what traders actually need to know before clicking open, there's a lot of thread.
What's different here
Everything runs in your browser. Nothing you type is sent anywhere, stored, or sold. No account. No email. The tools include fees and funding in the math, because those are not rounding errors — at 50x leverage, 0.055% taker fees per trade are 2.75% of your margin before price moves at all. Most calculators hide that.
The blog uses real backtest data and real trade results, not "trading is risky, please consult a financial advisor" filler. When a strategy loses money in testing, I say it loses money. When a rule like "set your stop before you open the trade" has actual statistical backing, I explain why.
How the site stays free
Some links go to exchanges and tools I personally use — Bybit, Binance, OKX, TradingView. If you sign up through those links I get a small commission. That's it. No sponsored calculator results, no paid rankings in the tool list. The full disclosure is here.
Questions or corrections: contact page. If a calculator gives wrong numbers for your exchange's specific margin tier, I want to know. And whatever you trade — don't get rekt.