Crypto volatility math you actually use

Volatility as a number you can read

Volatility is the word people throw around to mean 'this thing moves a lot.' For a crypto trader, three flavors of it are useful and they all live on the same chart in different shapes. Realized volatility is how much the asset actually moved over the last 30 days or so. Implied volatility is how much the options market thinks it will move going forward. ATR — Average True Range — is a smoothed average of recent per-bar range. None of them are exotic. All three are readable in a glance once you know what you are looking at.

Realized volatility tells you 'recent reality.' If BTC has been running at 60% annualized realized volatility, you are in a higher-vol regime than a year when it ran at 30%. Implied volatility tells you 'the market's bet about the future.' When implied is much higher than realized, the options market is pricing fear or excitement that has not shown up in price yet. After a big event, implied tends to collapse — that is what 'IV crush' refers to. You do not have to trade options to find this useful. The gap between realized and implied is a sentiment thermometer.

For day-to-day sizing on a $500 account, ATR is the most directly useful number. The 14-period ATR on your trading timeframe gives you an estimate of how far the asset usually moves per bar. If ATR on your daily chart is $1,500 on BTC, that is the normal daily swing — not a panic, not a rally, just the daily breathing. Sizing decisions made without knowing ATR are sizing decisions made blind to the asset's own behavior.

Here is the rule that actually keeps you in the game. Set your stop so that a normal one-ATR move against you equals one R of risk, not three. If you do that, you have already won the most important fight in crypto — the fight to stay alive long enough for the edge to play out. A trader who gets stopped by one-ATR noise on every entry has not lost their edge. They have lost their seat.

Recap. Three numbers — realized, implied, ATR. ATR is the one you will look at every day. Size so a normal one-ATR move against you is one R. The math is simple, and it is the difference between participating in the move and being scraped off the chart by it.