Charting Stocks: The Settings That Change What You See

Two people open the same stock over the same year and argue about what happened. One sees a collapse in the spring. The other sees a steady climb. Both are looking at real trades. Charting a stock means turning a record of trades into a picture, and that picture is built from settings: the chart type, the bar interval, whether old prices are adjusted for splits and dividends, whether premarket and after-hours trades are included, and whether the price axis is linear or log. Change any one of them and the stock appears to have done something different. Set them on purpose and leave them alone.

Choose a chart type

A line chart joins one price per period, almost always the close. It gives the cleanest view of a trend. It also hides everything that happened between closes.

An OHLC bar carries the open, high, low and close for each period: a vertical line spans the high and the low, a tick on the left marks the open, and a tick on the right marks the close. Candlesticks hold the same prices. They draw the stretch between the open and the close as a filled or hollow body, colored by whether the period finished above or below where it started, so a long upper wick, a tiny body, or a gap between one candle and the next is obvious at a glance in a way it never is on a line.

Pick by the question. For where the stock has been over five years, a line will do. For how buyers and sellers fought inside each session, use candles or bars.

Set the bar interval, then check your indicators

The interval is the time each bar covers: a minute, an hour, a day, a week. Shorter bars show more detail and far more noise. Longer bars smooth the noise away along with some of the detail you might have wanted.

The range is a separate setting. It’s how much history fits on the screen, and the quick buttons along the top or bottom of most charts (one day, one month, one year, five years) usually change both at once, picking an interval the tool thinks suits the range. A one-year view might arrive in daily bars on one platform and weekly bars on another. Set the interval yourself.

Indicators count bars, whatever the interval. A moving average set to 50 averages the last 50 bars on whatever interval is on screen, so the same setting means very different things as you flip between views.

The 50-day average that market commentary refers to is a daily-chart line. On a weekly chart the platform still draws a line labeled 50, and it’s a much slower one. Extended hours change the hourly version as well, because every premarket bar added to the day shortens the stretch of calendar time those 50 bars span. The 50-day and 200-day moving averages are built and read on daily bars, so check the interval before you compare a crossover with anyone else’s.

Adjust for splits and dividends

Price adjustment is behind the most convincing fake moves on any chart. When a company splits its stock, the share count goes up and the price per share goes down by the same ratio. Nothing happens to the value of anyone’s holding.

The unadjusted chart shows a cliff that cost nobody a cent. Any trendline, moving average or 52-week low that crosses that date is now measuring an accounting event. A reverse split does the opposite and paints a fake surge. Most charting tools let you switch split adjustment on, and for almost every purpose it should stay on.

Dividends are subtler. On the ex-dividend date the price typically drops by roughly the amount of the payout, since a buyer that morning no longer gets it. A dividend-adjusted chart rescales every earlier price so the line reflects what a holder actually earned, payouts included.

Every older price slips a little. Each new dividend repeats the process, so a support level drawn at $40 last year sits at $39.20 today, and after years of payouts the early part of an adjusted chart can show prices that never once printed on the tape. That’s correct for comparing long-run returns between two stocks. It’s wrong for checking where an old stop order sat, or whether a past fill was fair, because those questions are about prices that actually traded.

Decide whether extended hours belong on the chart

Premarket and after-hours trading tends to be thin, and a few trades can set a price that the regular session never comes near. Turning those bars on or off changes gaps, highs and lows.

A gap strategy needs extended hours off, because the gap is defined by the regular close and the regular open. Someone reacting to overnight news needs them on. What causes trouble is switching between the two without noticing, which is easy when daily bars on many tools ignore extended trading while intraday charts include it. Whether your feed carries extended-hours prints at all, and how fast, depends on the data you pay for, which the real-time market data guide covers.

Pick the scale

A linear axis spaces prices by dollars. A log axis spaces them by percentage. For a few weeks of a quiet stock the two look the same, and for a decade of a stock that went up tenfold they tell different stories about which years mattered. The full comparison, with a worked pair of moves, is in when to use a log scale chart. The short version: log for long views, linear for short ones.

Add volume, then draw lines

Put a volume pane under the price. It shows how many shares changed hands in each bar, and a breakout or a gap on heavy volume carries more weight than the same move on light trading. Reading volume bars goes through what to look for, including how to judge “heavy” against a stock’s own average.

Trend lines, support and resistance come last, after every other setting is fixed. Support is a price zone where declines have stalled before. Resistance is a zone where rallies have stalled. Both are drawn by hand, from bar highs and lows, and both move when the data underneath them changes: switch to dividend-adjusted prices and every old low drops, switch from linear to log and a straight trend line bends away from the bars it used to touch. Draw them on the final layout. Drawing a trendline covers anchor points.

Save one layout and keep it

Once the settings suit the way you trade, save them as a template so every new symbol opens the same way. Name it after its purpose, like “daily swing” or “weekly trend”. Then keep it.

The usual charting mistakes come from setting two differently built charts side by side:

• A screenshot someone posted, read against your own chart without checking its interval or scale.
• An old chart saved unadjusted, set beside a fresh one that has absorbed several years of dividends.
• A moving average copied from a daily chart onto a weekly one.
• A premarket high treated as resistance on a chart that doesn’t show premarket bars.

Before trusting any line on a chart, look at the settings bar. It takes seconds.