Question 1

What is IV rank and how is it different from implied volatility?

Accepted Answer

Implied volatility is a single number — the volatility the option market is currently pricing in — and on its own it tells you almost nothing, because 60% is high for one asset in a quiet month and low for another in a violent one. IV rank fixes that by placing today's implied volatility on its own recent range: it is the percentage of the way current IV sits between its lowest and highest readings over a lookback window, usually the past year. An IV rank of zero means volatility is at the cheapest it has been all year, one hundred means it is at the most expensive, and fifty means it is exactly mid-range. That context is the whole point. Option sellers want to sell when premium is expensive relative to its own history — a high IV rank — and buyers want to pay up only when it is cheap. This calculator takes your current IV and its high and low over the lookback and returns the rank, so a raw volatility figure becomes an actionable read on whether the market is charging a lot or a little for the same options right now.

Question 2

What is the variance risk premium and why does IV vs realized volatility matter?

Accepted Answer

The variance risk premium is the gap between what the option market charges for future volatility and what the asset actually delivers — implied volatility minus realized volatility. It is almost always positive, because option sellers demand to be paid for taking on the risk of a big move, and that structural overpricing is the edge premium sellers are harvesting. When IV sits well above realized — say implied 55% against a realized 42% — options are rich: the market is charging thirteen volatility points more than the asset has been moving, which favours strategies that collect premium. When implied drops below realized, options are cheap relative to actual movement, and buying premium or long-gamma structures gets the better deal. IV rank tells you where premium sits versus its own history; the variance risk premium tells you where it sits versus reality. This calculator shows both, because they can disagree — a high IV rank in a market that has started moving even harder is not the easy sell it looks like, and the realized comparison is what catches that.

Question 3

What is the expected move and how do I use it?

Accepted Answer

The expected move is the one-standard-deviation price range the option market is implying over your chosen horizon, and it is the most practical thing implied volatility gives you. It is the underlying price times the implied volatility times the square root of the time fraction of a year, which scales an annual volatility figure down to the days you actually care about. A one-standard-deviation move means roughly a 68% chance price finishes inside that band at expiry, and two standard deviations widens it to about 95%. Traders use it to sanity-check strikes: if you are selling a strangle, the short strikes usually sit at or beyond the one-sigma edges so price has to make an above-average move to threaten them; if you are buying a directional option, the expected move tells you how far the market already thinks price can travel, so you know whether your target is ambitious or already priced in. This calculator prints the one- and two-sigma dollar ranges for your horizon straight from the IV you enter, so you can place strikes against the market's own forecast rather than a guess.

Question 4

Should I always sell options when IV rank is high?

Accepted Answer

No — a high IV rank is a reason to look at selling, not a reason to sell blindly, and treating it as an automatic signal is how premium sellers get run over. Volatility is high for a reason: an event is coming, a trend has turned violent, or the asset is in a regime where big moves are the norm rather than the exception. The premium is rich precisely because the risk is real, and selling into a market that then keeps moving harder than implied — a rising realized volatility — turns a statistical edge into a steady bleed. That is why this calculator pairs IV rank with the variance risk premium: high rank plus implied comfortably above realized is the genuine sell setup, whereas high rank with realized catching up to or exceeding implied is a warning that the market is repricing risk for a reason. Volatility also mean-reverts, so a high rank does tend to fall over time, but the path there can include the exact spike that liquidates an undersized short. Use the rank to find candidates, the realized comparison to filter them, the expected move to place strikes with room, and defined-risk structures so a wrong read costs a number you chose in advance.

IVランク計算機

プレミアムがどこにあるのか、そしてそれが何を意味するのか

IV範囲全体での予想される動きとランク

ボラティリティを決定に変える数字

数学