Volume

Context & Mechanics

What volume measures

Volume counts the units traded in a period – shares, futures contracts or coins. Since every transaction has a buyer and a seller, volume measures participation, not direction: how much capital was actually involved in a move? A price rise on heavy volume reflects broad activity; the same rise on minimal turnover can come from a few orders in a thin order book.

Volume in chart analysis

Classic readings: a breakout above resistance is considered more reliable when volume is clearly above average. Rising prices on falling volume point to fading participation (divergence). Extreme volume spikes after extended moves often mark climax situations in which the last group of buyers or sellers enters the market. What matters is always the relative comparison with the instrument's own average, not the absolute number.

Volume-based tools

Many indicators build on volume: the VWAP weights the average price by turnover per period, on-balance volume (OBV) accumulates volume by price direction, and volume profile distributes turnover across price levels instead of time. All three answer the same basic question from different angles: at which levels and in which phases was the market really active?

Limits by market segment

Stocks and futures trade on central exchanges – their volume is complete and reliable. Spot forex is decentralized: platforms there show only tick volume (the number of price changes), which approximates real volume at best. Crypto volume in turn is spread across many exchanges of varying data quality. Volume analysis therefore always belongs in the context of the specific market.

Execution Example

A stock has traded an average of 500,000 shares per day and approaches resistance at €80. On breakout day, turnover rises to 2.1 million shares.

Relative volume: 2,100,000 ÷ 500,000 = 4.2× average volume.
Interpretation: the breakout above €80 is carried by real participation – historically, breakouts on below-average volume fail more often.
Follow-through check: if price holds above €80 the next day on still-elevated volume (e.g. 1.2 million shares), that argues for acceptance of the new level.
Warning signal: a drop back below €80 on 3 million shares is a failed breakout with heavy participation – a much stronger signal than the same drop on 300,000 shares.

Execution Risk & Errors

Reading volume as a directional signal although it only measures activity

Weighting breakouts without volume confirmation the same as confirmed ones

Equating forex tick volume with real traded volume

Looking at absolute instead of relative volume versus the instrument's own average

Including after-hours or illiquid sessions in volume comparisons

Frequently Asked

What does high volume indicate?

High participation: many units changed hands. It confirms that a move is carried by broad activity – it does not reveal direction, since every transaction has a buyer and a seller.

Why is there no real volume in forex?

Spot FX runs decentrally across banks and ECNs without a central exchange. Platforms therefore show tick volume – the number of price changes – which only approximates real traded volume.

What is the difference between volume and open interest?

Volume counts transactions in a period; open interest counts all open contracts of a derivatives market. High volume with rising open interest signals new positions; with falling open interest, position closing.

Which indicators are based on volume?

Among others VWAP (volume-weighted average price), on-balance volume (cumulative volume by price direction) and volume profile (turnover distributed across price levels). All measure where and when the market was really active.