What is a candlestick chart?
A candlestick chart organizes historical price observations into consecutive time intervals. Each candle normally records the open, high, low and close—OHLC—for one interval. Many market-data feeds also associate a candle with trading volume, although volume is a separate measurement rather than part of OHLC.
In crypto market interfaces, candlestick chart, K-line chart and K-Line commonly refer to this same chart format. “Candlestick” may also mean one individual bar within the chart. This terminology does not mean that every provider constructs its data in exactly the same way: the instrument, source trades, interval boundaries and volume units still need to be checked.
How trades become one candle
A market-data provider first selects an instrument and groups its recorded trades into a time bucket—for example, a five-minute or one-hour interval. It then derives four prices from the observations assigned to that bucket:
| Field | What it records for the interval |
|---|---|
| Open | The price of the first included trade or observation. |
| High | The highest included price. |
| Low | The lowest included price. |
| Close | The price of the last included trade or observation. |
The candle body spans the open and close. The upper and lower wicks extend to the high and low. When an extreme equals the relevant edge of the body, that side may have no visible wick.
This is an aggregation, not a replay of every trade. Four prices cannot show the exact order of all movements inside the interval. For example, OHLC values alone do not reveal whether the high occurred before or after the low.
What the body, wicks and colors encode
The position of the body shows the distance between open and close; the full high-to-low span shows the interval's recorded price range. A large body therefore describes a larger open-to-close difference, not necessarily high trading volume. Volume, when supplied, must be read separately.
Color usually indicates whether the close is above or below the open, but palettes and direction can vary by platform, region or user setting. “Green candle” is therefore not a universal technical definition. The OHLC values and chart legend are more reliable than color alone. TradingView's display documentation also documents configurable candle appearance.
Why the interval and completion state matter
A five-minute candle and a daily candle summarize different buckets. Changing the interval changes which observations are combined and can materially change the visible shape. Interval boundaries may also depend on the provider's time-zone or session rules. Binance's official Kline specification, for example, exposes an interval and a configurable time-zone parameter for interval interpretation.
The newest candle may be open, unconfirmed or otherwise unfinished. Its close is only the latest included value at that moment; a later trade in the same bucket can change the close, high, low, volume, body and wicks. OKX explicitly identifies candles as completed or uncompleted, while Kraken's OHLC endpoint states that its last entry represents the current, not-yet-committed timeframe. Analysis that requires a final OHLC value must distinguish a closed candle from a still-forming one.
Why two charts of “the same asset” may differ
Similar labels do not guarantee identical inputs. Before comparing candles, check at least the following:
- Instrument and source: spot, derivatives, index and mark prices are different series, and each venue normally records its own market.
- Interval boundary: a “day” or other bucket can start at a different time under different time-zone or session settings.
- Volume convention: volume may use the base asset, quote currency, contracts or another provider-defined unit.
- Data treatment: providers may handle no-trade intervals and historical corrections differently.
These differences do not by themselves show that one chart is wrong. They show that a candle is meaningful only together with its market, interval and data definition.
Reading one hourly candle without over-interpreting it
Suppose a fictional one-hour bucket opens at 100, trades as high as 108 and as low as 96, then closes at 103. Its body runs from 100 to 103, the upper wick reaches 108, and the lower wick reaches 96. The recorded range is 12 price units and the open-to-close change is 3.
The candle does not identify the sequence between those extremes, the reasons trades occurred, unexecuted orders or participant intentions. Many trade paths can produce the same OHLC. Candles compactly describe historical ranges and opening and closing levels; a single candle or named pattern does not establish causation or predict a later market move.
FAQ
Is trading volume part of OHLC?
No. OHLC refers only to open, high, low and close. A dataset may provide volume alongside those four fields, which is why the combined abbreviation OHLCV is also used. Always check the volume unit and methodology.
Is the close always final?
Only for a completed interval under the provider's rules. In a still-forming candle, “close” means the latest included value and can change until the interval is completed.
Can the candle color be used as the definition of price direction?
Not safely across platforms. Color settings vary. Compare the numerical open and close values and consult the chart legend.
Related reading
For a longer visual introduction, see the existing OKX candlestick chart guide. Return to the Crypto Glossary for other definitions.
Sources
- OKX API: market data and candlesticks — opening time, OHLC, volume fields and candle completion state.
- Coinbase Exchange API: get product candles — historic rates grouped into time buckets and OHLCV response fields.
- Kraken Developers: get OHLC data — treatment of the current, not-yet-committed interval.
- Binance Developers: Spot REST market data — Kline interval, time-zone interpretation, OHLC, volume and trade-count fields.
- TradingView: candlestick charts — candlestick display and configurable appearance.
