Ease of Movement Indicator: What the EMV Value Depends On
The ease of movement line prints a number, and that number can be moved by a factor of a hundred thousand without changing a single price or a single volume figure. The constant responsible sits inside the formula, it is picked rather than derived, and the widely read descriptions of the indicator publish at least four different values for it.
What survives that choice is the sign of the reading and the shape of the line. What does not survive is the size of the number, which is why a level read off one chart carries nothing across to another. A share of a running total behaves differently again, which is what governs an anchored VWAP.
Key takeaways
- The reading divides a change in the bar midpoint by a box ratio, and that box ratio holds volume, an arbitrary constant and the bar range.
- The constant differs between published descriptions, and the reading is directly proportional to it, so the same bar can print values a hundred thousand apart.
- Rearranged, the calculation multiplies the midpoint move by the bar range, which makes a wide bar raise the reading on its own.
- Its units are price squared per unit of volume, so no two instruments and no two platforms are on a common scale.
- A bar whose high equals its low, and a bar with no volume, both leave the calculation with no value to return.
Table of contents
What the Reading Actually Divides
Two quantities are built on every bar. The first is the distance the midpoint moved: take the high and the low of the current bar, average them, and subtract the same average from the bar before. That difference is positive when the midpoint rose and negative when it fell.
The second is the box ratio. Take the bar volume, divide it by a fixed constant, then divide the result by the bar high-low range. The single-bar reading is the first quantity divided by the second, and most platforms plot a moving average of it rather than the raw series.
Both halves are measured on one bar, and neither is a percentage or a bounded score. The volume term is the reason this tool is grouped with the volume bars printed under a candlestick chart rather than with the momentum family, and the box ratio is the part of it that deserves attention, because it carries two of the three inputs and the one number in the formula that nobody measured.
The Divisor Is a Choice, and the Sources Disagree
The constant that volume is divided by has no derivation behind it. It exists to keep the output in a range that fits on a chart pane, and the published descriptions do not agree on what it should be.
Two of the vendor references consulted for this page state 100,000,000. One broker education page gives a span running from 1,000 up to 1,000,000,000. Another site gives 1,000 up to 100,000,000, and a fourth narrows it to between 1,000,000 and 100,000,000. Each presents its figure as the normal one.
The consequence is arithmetic. Volume is divided by that constant before the box ratio is formed, so a larger constant produces a smaller box ratio, and a smaller box ratio produces a larger reading. The final value is directly proportional to whichever number was chosen.
| Divisor a description publishes | Reading for one identical bar | Sign and crossing points |
|---|---|---|
| 1,000 | one hundred-thousandth of the reference below | identical |
| 1,000,000 | one hundredth of it | identical |
| 100,000,000 | the reference | identical |
| 1,000,000,000 | ten times it | identical |
Read down the last column and the useful half of the indicator appears. Multiplying every value by a positive constant cannot change where the line sits relative to zero, cannot change when it crosses, and cannot change the direction it is travelling. Those three things are what the tool actually delivers.
Read down the middle column and the other half disappears. A reading of 12 on one chart and 0.00012 on another can be the same bar with the same volume, and any rule written around a numeric level is a rule about the platform configuration rather than about the market.
The Reading Is Proportional to the Bar Range
Dividing by the box ratio is the same operation as multiplying by its reciprocal, and writing it that way removes the fraction inside a fraction. The reading becomes the midpoint move, multiplied by the bar range, multiplied by the constant, divided by the volume.
That form makes a property visible that the divided form hides. Hold the midpoint move fixed, hold the volume fixed, and widen the bar range: the reading grows in step with the range. A bar that travelled a long way between its extremes and finished with its midpoint barely moved still lifts the value.
So the number is not a measure of distance travelled per unit of volume, which is how the indicator is usually introduced. It is a measure of distance travelled, scaled up by how far the price ranged while doing it, and scaled down by volume. The range term is doing work that the description rarely mentions, and it is the same quantity that a volatility measure built directly on the bar range reports on its own.
The units follow from the same rearrangement. A price multiplied by a price, divided by a volume, is not a price, not a ratio and not a percentage. A five-decimal currency pair, a stock quoted in whole cents and an index CFD produce values that share a name and nothing else, which is the second reason to read the line and not the level.
What the Volume Input Is on a Currency Chart
Every description read for this page documents the indicator on shares, where the volume figure is a count of units traded. A currency chart does not necessarily supply that.
MetaQuotes documents the bar structure its terminals use, and it carries two separate volume fields: a tick volume and a trade volume. The MetaTrader 5 help for the volumes indicator states that whether tick or real volumes are used is set in the indicator parameters, so the choice belongs to the configuration and not to the data.
Where a feed supplies tick volume, the denominator of the box ratio counts how many times the price updated inside the bar. The formula is unchanged and the line still plots.
What changed is the meaning of the answer. The reading now compares a midpoint move against update frequency, which rises with news and with session overlap, rather than against traded size. Reading it beside the spread of the bar the volume belongs to keeps that distinction visible.
There is a second consequence for MetaTrader specifically. The MQL5 technical indicator reference lists the functions the terminal provides for its built-in indicators, and no function for this one appears among them, so it arrives as a custom build whose volume source may not be exposed at all. Which volume type a given broker supplies for a given symbol is a per-broker fact, and it is not stated here.
The Bars Where There Is No Reading
The box ratio divides by the bar high-low range. A bar whose high equals its low has a range of zero, the box ratio cannot be formed, and the single-bar reading has no value. Flat bars are unusual on liquid instruments and ordinary on thin ones and in quiet hours.
A bar reporting zero volume produces a box ratio of zero, and dividing by zero leaves the same gap. Platforms fill it silently, by substituting a zero, by carrying the previous value forward or by skipping the bar, and that behaviour is rarely documented anywhere the user can see it.
One more result is worth separating from those two. When the midpoint is unchanged, the numerator is zero and the reading is zero whatever the volume was. A zero on this line is a statement about the midpoint alone, and an oscillator built on accumulation over the same volume series answers a different question at that same bar.
Two Origin Dates, Twenty-Three Years Apart
The attribution to Richard W. Arms Jr. is consistent across the descriptions consulted. The date is not. One broker education page places the indicator in 1967. Another site places it in May 1990 and names a magazine volume. Neither points to a document that can be retrieved and checked, and the two are twenty-three years apart.
No origin date therefore appears on this page. The same rule removes several other figures that circulate freely: the default averaging period, the levels that readings are said to be significant above or below, and the claim that the tool suits one chart timeframe rather than another. Each is repeated across sites and supported by none of them.
Nothing above should be read as evidence that those numbers are wrong. They are unverified, which is a different statement, and a page that repeats them would be passing along a figure it could not check.
Three Checks Before Reading the Line
Open the indicator settings and find the volume divisor, or establish that the build does not expose it. Establish next whether the volume series feeding it is tick or traded, since that decides what the denominator counts. Then look at the instrument during its quiet hours for flat bars, which are where the calculation goes missing.
All three are properties of the chart rather than of the market, and none of them is visible in the plotted line. Whether the result then belongs in a decision at all is the older question of whether a tool leads price or follows it.
Risk notice. This page is educational and describes how one technical indicator is calculated and what its published descriptions state. Nothing here is a recommendation to buy or sell any instrument, no indicator reading is a forecast, and no figure above is presented as a result anyone should expect. Leveraged trading carries a high risk of loss.