Stock Charts for Beginners: Price, Volume and Trend

A stock chart is a picture of past trades: each point, bar or candle summarizes the prices recorded during one interval, and a separate panel usually shows how many shares changed hands. Reading one means knowing what a single mark stands for, which interval it covers and how the axes are scaled. A chart describes what already happened, not what comes next.

Key takeaways

A candlestick packs four prices (open, high, low, close) into one mark; a line chart usually keeps only the close.
On a logarithmic scale, $10 to $20 and $100 to $200 span the same height because both are doublings; on a linear scale the second looks ten times taller.
Volume counts shares traded, not buying versus selling pressure.
A split makes the raw price drop without any loss to holders, so many data providers publish adjusted prices that rescale earlier history.

Chart types and time frames

Every chart type shows what the price did in each interval, at a different level of detail.

Line charts

A line chart joins one price per interval. TradingView's help page on line charts says its default is the closing price, which users can switch to the open, high, low or an average. A line of closes hides what happened inside each interval: a wide swing that ends unchanged looks like a quiet day.

Bar (OHLC) charts

OHLC stands for open, high, low and close. TradingView's guide to bar charts describes each bar as a vertical line whose top is the highest traded price and whose bottom is the lowest, with short ticks to the left and right marking the open and the close. A longer bar means a wider high-to-low range in that interval.

Candlestick charts

Nasdaq's glossary describes a candlestick chart as one that shows an asset's opening, closing, high and low prices for the period. The box is the real body, the part spanning the difference between the open and the close. In Nasdaq's convention a white body means the price rose (open at the bottom, close at the top) and a black body means it fell (open at the top, close at the bottom). The thin lines above and below, usually called wicks or shadows, mark the high and the low.

Time frames and intervals

Two choices set what a chart shows: the interval each mark covers (one minute, one day, one week) and the length of history displayed. One daily candle summarizes a whole session; the NYSE's core trading session runs from 9:30 a.m. to 4:00 p.m. Eastern, so the same session drawn with one-minute candles can be up to 390 marks. Switching intervals does not change the trades, only which movements stay visible. The length of history matters too: the same stock can look like it is climbing on a one-month view and falling on a one-year view, as the worked example below shows.

Linear versus log price scales

On a linear axis, equal vertical distances mean equal dollar changes. On a logarithmic (log) axis, equal vertical distances mean equal percentage changes.

position = log10(price)
distance between two prices = log10(price_B) - log10(price_A) = log10(price_B / price_A)

Move	Dollar change	Percent change	Log-axis distance (log10 units)
$10 to $20	+$10	+100%	0.301
$100 to $200	+$100	+100%	0.301
$10 to $11	+$1	+10%	0.041
$100 to $110	+$10	+10%	0.041

Illustrative example, computed from the formula above. Both doublings have a ratio of 2, and log10(2) is about 0.301, so they look identical on a log chart, while on a linear chart the $100-to-$200 move is ten times as tall. A fall from $20 back to $10 (a 50% loss) spans the same 0.301 downward. Neither scale is wrong; check which one a chart uses before comparing the steepness of two moves.

Volume, trend and zones

What volume shows and does not

Nasdaq's glossary defines volume as the daily number of shares of a security that change hands between a buyer and a seller. On a chart it usually appears as a column under each candle or bar. That definition sets its limits:

It counts shares traded. Every trade has a buyer and a seller, so a tall column does not mean buyers outnumbered sellers or the reverse.
It is relative. 2,000,000 shares can be a heavy day for one stock and an ordinary morning for another, so compare a column only with the same stock's history.
It is separate from price movement. A small body can come with heavy volume and a large body with light volume.

Trend, support and resistance

Nasdaq's glossary defines a trend simply as the general direction of the market. Many chart readers describe an uptrend as a series of higher highs and higher lows, and a downtrend as lower highs and lower lows. Five bars are a sample, not a trend.

The same glossary describes a support level as a price below which it is supposedly difficult for a security to fall, identified by where it bottomed out in the past, and a resistance level as a price above which it is supposedly difficult to rise. "Supposedly" is the glossary's own word.

Treat these as zones rather than exact lines: past turning points at $48.60 and $48.80 are better described as a band from $48.60 to $48.80 than as one price. A band drawn on past data shows where price turned before; it does not say it will turn there again.

Adjusted and unadjusted prices

Raw price history can contain drops that are not losses. Investor.gov, the SEC's investor education site, explains that a stock split increases the number of shares without changing shareholders' equity. In its example, 100 shares at $100 become 200 shares at $50 after a two-for-one split. A raw chart would show the price falling 50% overnight, though the holding was still worth $10,000.

To keep history comparable, many data providers rescale earlier prices. Yahoo's help page on the adjusted close defines it as the closing price after adjustments for all applicable splits and dividend distributions, following Center for Research in Security Prices (CRSP) standards. In a 2-for-1 split, pre-split data is multiplied by 0.5; in a 4-for-1 split, by 0.25.

So check whether a series is split-adjusted, dividend-adjusted, both or neither before comparing its old prices with actual trades: an adjusted chart shows prices never quoted on those dates.

A worked week and its pitfalls

Five-day example

Illustrative example with invented numbers; it is not a real stock. Derived columns follow from the open (O), high (H), low (L) and close (C).

body = |C - O|
upper wick = H - max(O, C)
lower wick = min(O, C) - L
range = H - L
change vs open = (C - O) / O

Day	Open	High	Low	Close	Volume	Candle	Body	Upper wick	Lower wick	Change vs open
Mon	50.00	51.50	49.50	51.00	1,200,000	Up	1.00	0.50	0.50	+2.00%
Tue	51.00	52.00	50.50	50.75	900,000	Down	0.25	1.00	0.25	-0.49%
Wed	50.75	50.90	48.60	49.00	2,100,000	Down	1.75	0.15	0.40	-3.45%
Thu	49.00	50.00	48.80	49.80	1,000,000	Up	0.80	0.20	0.20	+1.63%
Fri	49.80	52.50	49.60	52.00	1,800,000	Up	2.20	0.50	0.20	+4.42%

Reading the week:

Range. The five-day high is 52.50 (Friday) and the low is 48.60 (Wednesday), a range of 3.90, or about 8.02% of the low.
Volume. Total volume is 7,000,000 shares, an average of 1,400,000 a day. Wednesday's 2,100,000 is 1.5 times that average on a down candle with a 1.75 body; the column says many shares changed hands, not who was more eager.
Wicks. Tuesday's body is only 0.25, but its upper wick of 1.00 shows price traded a dollar above the open, and $1.25 above where it closed. A line chart of closes would show none of this.
Trend language. Wednesday's low (48.60) is followed by higher lows on Thursday (48.80) and Friday (49.60), and Friday's high (52.50) tops Tuesday's (52.00). That is uptrend language, but it describes one week.

Same week, different answers

Measured from	To	Calculation	Change
Monday open (50.00)	Friday close (52.00)	52.00 / 50.00 - 1	+4.00%
Monday close (51.00)	Friday close (52.00)	52.00 / 51.00 - 1	+1.96%
Monday close (51.00)	Wednesday close (49.00)	49.00 / 51.00 - 1	-3.92%
Wednesday close (49.00)	Friday close (52.00)	52.00 / 49.00 - 1	+6.12%

The same five days give anything from a 3.92% loss to a 6.12% gain, depending only on the window, which is why any chart-based claim needs stated start and end dates.

Cherry-picked windows

A window chosen after the fact can make almost any story look right, so check a chart with a longer window and another start date. FINRA's page on evaluating performance makes a related point: comparing returns over several years shows when an investment did well and when its returns were weaker.

Survivorship

Nasdaq's glossary explains survivorship bias with fund managers: a group studied because it survived ten years looks better than the full group, since some dropped out after poor performance. By the same logic, a screen built only from stocks still trading today omits those that were delisted.

Treating shapes as signals

Technical analysis, in Nasdaq's glossary, seeks to detect and interpret patterns in past security prices. The abstract of Lo, Mamaysky and Wang's study of technical pattern recognition (Journal of Finance, 2000) notes that geometric shapes in price charts are often "in the eyes of the beholder" and proposes a systematic, automatic way to detect them. Comparing the overall distribution of daily returns on US stocks from 1962 to 1996 with the distribution conditioned on specific patterns, the authors found that several technical indicators provided incremental information and may have some practical value. That is one historical sample and a mechanical method, not evidence that a shape drawn by hand on today's chart will pay off.

Moving averages, volatility measures and named candlestick patterns build on these basics and are separate topics.

Frequently asked questions

Does a stock split change what a company is worth?

According to Investor.gov, a split increases the number of shares without changing shareholders' equity and, unlike issuing new shares, does not dilute existing holders' ownership. If the company pays a dividend, the dividend per share falls proportionately. The split itself does not change the combined value of a holder's shares.

What does a reverse split look like on an adjusted chart?

A reverse stock split cuts the number of shares and raises the price per share; in Nasdaq's 1-for-3 example, the post-split price is three times the pre-split price. Yahoo's help page says that for a 1-for-5 reverse split, pre-split data is multiplied by 5, so older prices line up with the new share count.

How does a dividend change adjusted prices?

Yahoo's help page uses a multiplier based on the dividend as a share of the price: a $0.08 cash dividend with a prior close of $24.96 gives 1 - 0.08/24.96, or 0.9968, applied to earlier data. Dividend-adjusted closes therefore sit slightly below the prices actually quoted before the ex-dividend date.

Is a bigger candle body a sign of heavier trading?

No. The body measures the gap between the open and the close, while volume counts shares that changed hands. A small-bodied day can still carry the week's tallest volume column.

What does a candle color mean if it isn't white or black?

Nasdaq's glossary uses white for up and black for down, but platforms differ. TradingView's bar-chart guide, for example, says bars are usually colored green for upward and red for downward movement, and lets users change both colors in settings. The platform's legend or settings decide.

A checklist for your next chart

Identify what one mark represents: the close only, or open, high, low and close.
Read the interval and the start date, then change both and see whether the picture changes.
Check whether the price axis is linear or logarithmic before comparing the steepness of two moves.
Check whether prices are adjusted for splits, dividends or both.
Compare volume only with the same stock's own history, and keep it separate from candle size.
Describe support, resistance and trends as past behavior in a zone, and write down what evidence beyond the chart supports any decision.