horizontalLine

Draws a flat line across the chart at a specific price level. Traders usually use it to mark support, resistance, or key levels like round numbers (e.g., 1.2000 in Forex).

Syntax

horizontalLine(time, price, styles?, text?)

Parameters

• time The candle time where the line begins. You can use time(0) for the current candle.

• price The price level where the line will be placed (e.g., closeC(0) or 100).

• styles (optional) Customize how the line looks:

  • linecolor: color of the line (e.g. color.red)

  • linewidth: thickness of the line

  • linestyle: solid, dashed, dotted, etc.

  • showLabel: true/false to display the label

  • textcolor: color of the label text

• text (optional) A short label to display next to the line (if showLabel: true).

Return Value

• string — The unique id of the drawing.

Example

//@version=1
init = () => {
    // Place the indicator on the main price chart
    indicator({ onMainPanel: true, format: 'inherit' });
};

onTick = () => {
    // Every 30 candles, create a new horizontal line
    if (index % 30 === 0) {
        // Select the current candle close as the horizontal level
        const level = closeC(0);

        // Draw the line starting at the current candle time and chosen level
        // - Color: red
        // - Thickness: 2
        // - Label: "Key Level"
        horizontalLine(
            time(0), 
            level,
            { linecolor: color.red, linewidth: 2, showLabel: true },
            'Key Level'
        );
    }
};

This example draws one red horizontal line at the current closing price every 30 candles, labeled “Key Level.”

Result

Tips

• Use horizontal lines to highlight support/resistance zones.

• Try dashed lines (linestyle: 2) for less important levels, and solid for key levels.

Warning

• If you forget to include price, nothing will be drawn.

• If you pass text but don’t set showLabel: true, the label won’t appear.

Good Practice

• Keep the number of horizontal lines low so your chart doesn’t get cluttered.

• Use consistent colors — for example, red for resistance and green for support.