VIX1D Explained: A Full Quant Guide to Forecasting Daily SPX Movement Using Volatility & True Range
In the world of 0DTE trading, volatility is everything. You can trade the cleanest iron condor, butterfly, or delta-neutral hedge, but if you don’t understand the volatility environment you’re operating in, the trade becomes guesswork. This is why VIX1D, one of the newest and most important volatility indices, has quickly become a core tool for professional intraday and 0DTE traders.
This guide is an in-depth, 1500+ word breakdown of VIX1D: what it is, how it’s constructed, why it behaves differently from VIX, and how to use it to forecast the size of today’s SPX move. You’ll also learn how to validate the predicted movement using True Range (TR) and how to incorporate both into a practical 0DTE trading framework.
What Exactly Is VIX1D?
VIX1D is the one-day version of the traditional VIX Index. While VIX measures 30-day forward volatility implied by SPX options, VIX1D measures volatility for just the next trading session — effectively “today + tomorrow until today’s close.”
This is extremely important for 0DTE traders because it gives a much clearer view of intraday risk and expected range expansion. The market now trades SPXW options with Monday–Friday expirations, which means the market continuously reprices ultra-short-dated volatility throughout the day. VIX1D captures this repricing.
How VIX1D Is Constructed
Similar to VIX, VIX1D aggregates weighted mid-prices of SPX options across a wide strike range. However:
- VIX uses options expiring around 30 days out
- VIX1D uses options expiring today (near-term) and the next available expiry (next-term)
Examples:
- If today is Tuesday → VIX1D uses Tuesday & Wednesday expirations
- If Friday → uses Friday & Monday expirations
Because it uses 0DTE and 1DTE options, VIX1D is dramatically more sensitive to:
- Economic announcements
- Intraday trends
- Dealer hedging flows
- Gamma positioning
- Opening gap risk
- Liquidity conditions
For traders dealing with daily income or short premium, this real-time responsiveness is invaluable.
VIX vs VIX1D — Key Differences Every Trader Should Know
Although they measure volatility using similar formulas, VIX and VIX1D behave very differently.
VIX (30-day volatility)
- Slow to react
- Represents macro expectations
- Influenced by OTM put skew from institutions
- Useful for medium-term volatility regime analysis
VIX1D (1-day volatility)
- Fast-reacting
- Shows intraday panic or complacency
- Driven heavily by 0DTE flows
- Best for short-term range projections
One major insight comes from comparing the two:
- When VIX1D >> VIX, intraday fear is extremely elevated
- When VIX1D << VIX, the market expects a calm trading day
This spread becomes a volatility shock detector.
How to Use VIX1D to Forecast Today’s Expected Move
The most valuable application of VIX1D for 0DTE traders is converting volatility into an expected daily SPX move. This gives objective, model-based guidance on the price range SPX is likely to travel within today.
The Formula
Expected Daily Move (points) ≈ SPX Price × (VIX1D / √252)
Why √252? Because there are roughly 252 trading days in a year. Annualized volatility must be de-annualized for daily use.
Example
SPX = 5000
VIX1D = 10%
√252 ≈ 15.87
Expected Move = 5000 × (0.10 / 15.87) ≈ 31.5 SPX points
Practical Uses
- Set iron condor wings outside expected move
- Anchor butterfly centers at ± expected move
- Use expected move as “stop signal” for directional trades
- Use half expected move as rebalancing radius for delta-neutral trades
This creates structured, rules-based decision-making.
True Range (TR) — Validating the Forecast
Expected move is a forecast. True Range (TR) measures actual movement. TR is one of the most robust measures of realized volatility because it captures gap risk, wick extensions, and full low-to-high intraday behavior.
True Range Formula
TR = max(
High – Low,
|High – Previous Close|,
|Low – Previous Close|
)
Why TR Matters
TR captures:
- Gaps up or down
- Intraday swings
- News-driven volatility
- Reversal zones
By comparing TR with VIX1D expected move:
- If TR < expected move → volatility overpriced
- If TR ≈ expected move → model performing well
- If TR > expected move → volatility shock / tail event
This comparison is powerful for judging whether SPX is in a compressed or expanded volatility environment.
Volatility Regime Detection Using VIX1D/VIX Spread
When VIX1D > VIX
- Intraday risk elevated
- Greater likelihood of trend days
- Good for wide iron condors / butterflies
- Directional moves more likely
When VIX1D < VIX
- Lower intraday volatility
- Mean-reversion days more common
- Suitable for narrow spreads
- Better fill quality
This ratio is essentially a “market fear thermometer” for 0DTE traders.
Practical 0DTE Workflow Using VIX1D
Step 1 — Read VIX1D & VIX
Define the volatility environment immediately after the market opens.
Step 2 — Compute Expected Move
Set your probabilistic boundaries for the day.
Step 3 — Compare Recent TR Levels
Understand whether realized volatility supports the forecast.
Step 4 — Identify Trend (EMA50/200)
Trends change the distribution of expected range.
Step 5 — Select Strategy Type
- Low vol → narrow spreads, premium selling
- High vol → wide condors, wider butterflies
- Vol shock → delta-neutral hedging
Step 6 — Size Based on Volatility Risk
When VIX1D spikes, reduce size. When VIX1D compresses, position size may expand.
Video Breakdown — VIX1D & True Range
Subscribe for Daily Quant Insights
Join thousands of traders who use volatility models, expected move math, and systematic 0DTE frameworks to improve consistency.