Technical Glossary / Chart Types & Price Representation
Area Chart
A line of price, or of two series, with the region between the line and a baseline filled in.
Teaching sketch. It shows the shape, not a live quote and not a trade signal.
Definition
An area chart fills the space under a line. With one series it is the same idea as a mountain chart. With two series the fill can mark the gap between them, such as price and a moving average, or two indexes.
How it works
The fill is a visual weight. It does not change the calculation of the line. If the baseline is zero, a price series that never goes near zero looks like a large block. That block is not "size."
How to identify it
A coloured region bounded by a price line. Confirm whether you are looking at one series against zero or at the spread between two series.
How traders use it
Area charts suit cumulative lines such as on-balance volume, or a comparison of two closes. Trade decisions that need the range belong on candles.
Common mistakes
Comparing two area charts whose baselines differ and concluding that the taller fill is the stronger trend.
Limitations
Fill can hide the scale. Always read the axis. The chart still omits the high and the low unless those are the lines being drawn.
This note explains the term. A sketch shows the shape of the idea. Neither is a recommendation, a signal, or a comment on any security. Indicator settings and exchange conventions differ. Check the live chart and the contract specification before you use a number.