Value area high and low (VAH, VAL): the 70% value area and the 80% rule
What is the value area in volume profile?
The value area is the price range where roughly 70% of a period's volume traded. Its upper boundary is the value area high (VAH) and its lower boundary is the value area low (VAL). Value area high and low are two of the most watched levels in auction-based trading.
Why 70%? The idea comes from statistics: in a roughly normal distribution, about 68% of observations fall within one standard deviation of the mean. Market profile pioneers rounded that to 70% and used it to describe the "accepted" price range of a session. Prices inside the value area are where most business happened. Prices outside it were visited but not accepted as fair.
The value area always surrounds the point of control, the single busiest price. To see how it fits the bigger picture, start with the pillar guide on volume profile.
VAH and VAL meaning in plain words
- VAH (value area high): the top of accepted value. Above it, the market thought prices were too high to do much business, at least for that period.
- VAL (value area low): the bottom of accepted value. Below it, prices were seen as too cheap and attracted buyers, or were simply not accepted.
- POC: the centre of gravity inside the value area.
Think of the value area as the "fair" zone and VAH and VAL as the fences. When price leaves the fence and comes back, that tells you something. When price leaves and stays out, that tells you something different. Most value area trading strategies are built around this simple idea.
How to calculate the 70% value area
The standard method is incremental. It is easy to follow by hand.
- Total the volume of the profile and work out 70% of it.
- Start at the POC. Its volume is your running total.
- Look at the two rows directly above and the two rows directly below the current value area. Add the volumes of each pair.
- Add the larger pair to the value area and to your running total.
- Repeat until the running total reaches 70% of the total volume.
- The highest row included is the VAH; the lowest is the VAL.
TPO value area
On a market profile (TPO) chart, the same process uses TPO counts instead of volume. The result is usually similar on liquid futures but can differ on days where price spent a long time in a quiet range. See market profile vs volume profile.
Where today opens relative to yesterday's value
One of the most useful habits is to compare today's open with yesterday's value area. It frames the first hour.
| Open location | What it suggests | What traders watch |
|---|---|---|
| Inside yesterday's value | Balance; the market is still happy with yesterday's prices | Rotation between VAH and VAL; fades at the edges |
| Above VAH, accepted | Buyers moving value higher | VAH acting as support; developing POC moving up |
| Below VAL, accepted | Sellers moving value lower | VAL acting as resistance; developing POC moving down |
| Outside value, then back in | The outside move was rejected | The 80% rule (below) |
"Accepted" usually means price spends at least an hour (two 30-minute periods) outside value without returning. A brief poke outside that comes straight back is not acceptance.
The 80% rule explained
The 80% rule is a classic market profile idea. It says that if the market opens outside the previous session's value area, then re-enters it and stays inside for two consecutive 30-minute periods, there is a high chance it will travel across the whole value area to the other side.
The logic: an open outside value is a test of new prices. If the market comes back inside and stays there, the test failed. The previous value is accepted again, and the natural rotation is to the opposite edge.
How traders apply it
- Note yesterday's VAH, VAL and POC.
- Today opens above VAH (or below VAL).
- Price returns inside the value area.
- It holds inside for two full 30-minute TPO periods.
- The opposite edge becomes the reference objective; the POC is the halfway check.
Despite the name, the "80%" is a rule of thumb from older studies, not a fixed probability. Results vary by market and period, so treat it as a framework to test, not a promise. On NIFTY, gap days around big global news often behave differently from quiet days.
Value area trading strategy ideas
1. Rotation inside value
On a balanced day that opens inside value, price often rotates between VAH and VAL. Traders look for rejection at an edge, such as exhaustion or absorption on the footprint, and use the POC and the opposite edge as references.
2. Breakout and acceptance
When price leaves the value area and holds outside, with the developing POC following, value is migrating. The old VAH (on an up-move) or VAL (on a down-move) often becomes the retest level. A retest that holds with supportive delta points to acceptance.
3. Failed breakout back into value
A push above VAH that quickly falls back inside is a sign of rejection. This is the setup behind the 80% rule and overlaps with breakout vs fakeout analysis. Traders often combine it with a liquidity sweep reading when the poke runs stops above a prior high.
4. Value area relationships across days
- Higher value: today's value area entirely above yesterday's suggests a bullish auction.
- Lower value: entirely below suggests a bearish auction.
- Overlapping value: suggests balance and range trading.
- Inside value: today's value inside yesterday's often comes before a breakout.
Real versus weak value area levels
Not all VAH and VAL levels behave the same. Some clues make an edge more meaningful:
- Clean distribution: a D-shaped profile gives sharp, reliable edges. A flat or double-distribution profile gives fuzzy ones.
- LVN at the edge: if VAH or VAL sits near a low volume node, the edge is sharper.
- Confluence: VAH near a prior high, VWAP band or round number attracts more attention.
- Composite agreement: a VAL that matches a multi-day composite VAL carries more weight than a single-session one.
A weak edge is one inside a trend day profile, where value kept moving and the 70% range is long and thin. There, VAH and VAL are just arithmetic, not real boundaries of acceptance.
Worked example: NIFTY and the 80% rule
Illustration only; the numbers are invented to show the process.
Yesterday NIFTY futures formed a normal profile: VAL 24,380, POC 24,440, VAH 24,500. Today the market gaps up and opens at 24,545 after positive global cues.
The first 30-minute period makes a high of 24,570, but buying dries up. The footprint shows exhaustion at the top and delta turning negative. In the second period, price falls back to 24,490, inside yesterday's value. The third period also stays inside, trading between 24,460 and 24,500. The 80% rule condition (two periods inside value) is now met.
An auction trader would now treat the POC at 24,440 as the first checkpoint and VAL at 24,380 as the far edge. If price later reclaims 24,500 and holds above it, the idea is invalid and the gap-up may be accepted after all. Defining that invalidation in advance matters; trading F&O carries a high risk of loss and no rule works every time.
Common mistakes with VAH and VAL
- Treating VAH and VAL as walls. They are references, not certain turning points.
- Calling acceptance too early. One 5-minute candle outside value is not acceptance. Give it time.
- Using a broken profile. Include only regular session data (9:15 to 15:30 IST) unless you deliberately want overnight data.
- Applying the 80% rule on every day. It works best when the open is just outside value and the market is not in a strong trend.
- Ignoring expiry effects. On weekly expiry days, option hedging flows can pin price near strikes and distort normal value behaviour.
Value area checklist
- Is the prior profile clean enough to trust its edges?
- Where did today open relative to yesterday's value?
- Is price accepting or rejecting outside value?
- Is the developing POC moving?
- Any confluence at VAH or VAL?
- What does order flow show at the edge?
Seeing it on the TradingMarble chart
The TradingMarble chart marks the point of control and the value area high and low on session and range profiles, and can carry the previous session's levels into today. With the footprint beside them, you can watch how buyers and sellers trade at each edge and study how past openings outside value played out. The features page lists the tools.
Conclusion: value area high and low as fences of fair price
The value area holds about 70% of volume; value area high and low are its fences. Comparing today's price with yesterday's VAH and VAL tells you whether the market is balancing, building new value, or rejecting a move. The 80% rule and the rotation, breakout and failed-breakout ideas give you a structured value area trading strategy. Combine it with order flow and you will read NIFTY and BANKNIFTY auctions with much more clarity.
Frequently asked questions
What is VAH and VAL in trading?
VAH means value area high and VAL means value area low. They are the upper and lower edges of the value area, the price range that holds about 70% of a period's traded volume. Traders use them as the boundaries of accepted, fair price.
Why is the value area 70%?
The 70% figure comes from statistics. In a normal distribution, about 68% of observations fall within one standard deviation of the mean. Market profile developers rounded this to 70% to describe the range where most of the session's business took place.
What is the 80% rule in market profile?
The 80% rule says that if price opens outside the previous session's value area, comes back inside, and stays there for two consecutive 30-minute periods, it often travels across the full value area to the other edge. It is a rule of thumb, not a fixed probability.
How do you calculate the value area?
Start at the point of control and add volume from the neighbouring rows above and below, always choosing the busier side, until the running total reaches 70% of the period's volume. The highest included price is the VAH and the lowest is the VAL.
Is the value area the same as the VWAP bands?
No. VWAP bands are drawn at standard deviations from the volume-weighted average price. The value area is built from the volume histogram around the point of control. Both describe fair value, and they often overlap, but they are calculated differently.
Which is better, TPO or volume value area?
Neither is better in every case. A volume value area shows where the money traded, while a TPO value area shows where price spent the most time. On liquid NIFTY futures they are often close; when they differ, many traders give more weight to the volume version.