EquiVolume Chart
A chart where each period’s box height shows the price range (high to low) and its width shows trading volume — fusing two dimensions of market data into a single, intuitive shape.
// 01 — The chart
What it looks like
An EquiVolume chart showing 8 trading days. Each box’s height represents the price range (high minus low) and its width represents trading volume. Wide boxes like Thursday and Wednesday show heavy trading; narrow boxes like Friday show light volume. Green indicates close above open; red indicates close below open.
// 02 — Definition
What is an EquiVolume chart?
An EquiVolume chart is a financial visualization invented by Richard W. Arms Jr. that merges price range and trading volume into a single box for each time period. The vertical dimension (height) of each box spans from the period’s high to its low, while the horizontal dimension (width) is proportional to the period’s volume.
This design eliminates the need for a separate volume histogram beneath the price chart. A wide, tall box immediately signals a high-volume, high-volatility session. A narrow, short box shows a quiet session with little price movement and light trading. The visual “weight” of each box corresponds to its market significance.
Color further encodes direction: green (or white) boxes mean the close was above the open (bullish), while red (or black) boxes mean the close was below the open (bearish). Together, height, width, and color provide three dimensions of market information in a single glyph — making EquiVolume charts among the most information-dense financial chart types.
Origin: Richard W. Arms Jr. introduced the EquiVolume chart in the 1970s. He also created the Arms Index (TRIN), another tool that links price and volume. His goal was to make volume an integral part of price analysis rather than a secondary afterthought relegated to a bottom panel.
// 03 — Anatomy
Parts of an EquiVolume chart
// 04 — Usage
When to use it — and when not to
- You want to see price range and volume in a single view without a separate panel
- Identifying accumulation and distribution patterns — wide boxes at support/resistance
- Analyzing breakout quality — a breakout on high volume (wide box) is more reliable
- Comparing volatility and volume across different trading sessions
- Teaching the relationship between volume and price movement visually
- You want a more information-dense alternative to candlestick + volume charts
- You need exact OHLC values — EquiVolume shows only high, low, and direction
- Your audience is unfamiliar with volume-width encoding — it's not intuitive at first
- You're analyzing instruments with very low or erratic volume where width varies wildly
- You need a uniform time axis — EquiVolume boxes have variable widths
- You want to overlay technical indicators designed for fixed-width bars
- You're comparing multiple securities — differing volume scales make comparison difficult
// 05 — Reading guide
How to read an EquiVolume chart
Follow these steps to extract maximum information from each box.
Read the box shape first
A tall, wide box is the most significant — it signals both high volatility and heavy volume. A short, narrow box is the least significant — low volatility, low volume. Train your eye to scan for the largest, most 'square' boxes as the key sessions.
Check the color for direction
Green boxes mean the close was above the open — buyers won the session. Red boxes mean the close was below — sellers won. A tall green box with high volume is strongly bullish; a tall red box with high volume is strongly bearish.
Look for 'power boxes' at key levels
A wide box (high volume) that breaks above a resistance level or below a support level is called a 'power box.' Arms considered these the most reliable breakout signals because volume confirms the price move.
Watch for narrow boxes in trends
If a strong uptrend suddenly produces a narrow, short box, volume is drying up. This often precedes a reversal or consolidation. Similarly, narrow boxes at the end of a downtrend suggest selling is exhausting itself.
Compare box shapes over time
Are the boxes getting wider or narrower as a trend progresses? Widening boxes confirm the trend is gaining participation. Narrowing boxes suggest the trend is losing conviction, even if the direction hasn't changed yet.
// 06 — Pitfalls
Common mistakes
Confusing width with time
Fix: Box width represents volume, not time. Each box covers the same time period (one day, one hour, etc.), but high-volume days appear wider. If you need a uniform time axis, EquiVolume isn't the right chart type.
Ignoring the aspect ratio of boxes
Fix: The shape of the box matters as much as its size. A very wide, very short box (high volume, low range) suggests accumulation/distribution — big players are trading heavily without moving the price. A tall, narrow box (low volume, high range) suggests a gap or illiquid move.
Using EquiVolume for thinly traded instruments
Fix: Stocks or crypto tokens with very low and inconsistent volume produce wildly varying box widths that are hard to compare. EquiVolume works best for liquid instruments with relatively stable volume patterns.
Not understanding that open and close are lost
Fix: Standard EquiVolume boxes show only high, low, volume, and direction (via color). The exact open and close values within the range are not encoded in the box shape. If you need precise OHLC, use candlesticks.
Comparing EquiVolume charts across instruments
Fix: Because width is proportional to volume, a chart of Apple (millions of shares) will look entirely different from a chart of a small-cap stock. Volume scales must be normalized before cross-instrument comparison.
// 07 — In the wild
Real-world examples
Institutional breakout confirmation
Fund managers use EquiVolume charts to confirm breakouts. A stock breaking above resistance with a wide green box (heavy volume) is far more likely to sustain the move than one breaking out on a narrow box (light volume). The visual width difference makes this assessment instant.
Accumulation/distribution analysis
Market analysts look for sequences of wide, short boxes near support levels — indicating that large institutions are accumulating shares (heavy volume) without pushing the price up. Conversely, wide, short boxes at resistance suggest distribution.
Arms' own hedge fund analysis
Richard Arms used EquiVolume charts extensively in his own trading and fund management. He would identify 'ease of movement' — when prices move significantly on little volume (tall, narrow boxes) versus heavy effort with little movement (wide, short boxes).
// 08 — Quick reference
Key facts
// 09 — Variations
Types of EquiVolume charts
The core concept of encoding volume as width adapts to different analysis needs.
Standard EquiVolume
The classic format — boxes touching side by side, width proportional to volume, height spanning high to low. Color indicates bullish or bearish.
Hollow EquiVolume
Bullish boxes are drawn as outlines (hollow) while bearish boxes remain filled. Adds a visual distinction similar to hollow candlesticks.
CandleVolume
A hybrid that adds wicks (shadows) to EquiVolume boxes, combining candlestick OHLC detail with volume-encoded width.
With ease-of-movement overlay
Adds Arms’ Ease of Movement (EMV) indicator as a moving average line, quantifying the relationship between price change and volume.
// 10 — FAQs
Frequently asked questions
What is an equivolume chart?+
An EquiVolume chart is a financial visualization invented by Richard W. Arms Jr. that merges price range and trading volume into a single box for each time period. The vertical dimension (height) of each box spans from the period's high to its low, while the horizontal dimension (width) is proportional to the period's volume.
When should you use an equivolume chart?+
Use an equivolume chart when you want to see price range and volume in a single view without a separate panel. It also works well when identifying accumulation and distribution patterns — wide boxes at support/resistance, and when analyzing breakout quality — a breakout on high volume (wide box) is more reliable.
When should you avoid an equivolume chart?+
Avoid an equivolume chart when you need exact OHLC values — EquiVolume shows only high, low, and direction. It is also a poor fit when your audience is unfamiliar with volume-width encoding — it's not intuitive at first, or when you're analyzing instruments with very low or erratic volume where width varies wildly.
How is an equivolume chart different from a candlestick chart?+
Both an equivolume chart and a candlestick chart can look similar at first glance, but they answer different questions. Reach for an equivolume chart when the comparisons and patterns it was designed to reveal match what you need to communicate, and choose a candlestick chart when its particular strengths better fit your data and audience.
Is an equivolume chart suitable for dashboards?+
Yes — an equivolume chart can work well in dashboards as long as the panel is large enough for readers to perceive the encoded values, has a clear title, and includes the legend or axis labels needed to interpret it.
What category of chart is an equivolume chart?+
EquiVolume Chart belongs to the Financial family of charts. Charts in that family are designed to answer the same kind of question, so they often work as alternatives when one doesn't quite fit your data.