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How do Candle Charts in Reports work?

Learn how candle charts summarize your data in Heads Up Reports

Brian Haltom avatar
Written by Brian Haltom
Updated over 2 weeks ago

Candle charts in the Reports section are designed to help you visualize trends over time by grouping data into summarized time blocks. Each candle represents a statistical summary—minimum, maximum, and average—over a specific time range.

This chart type is most commonly used for tracking glucose levels, but the same logic applies to other time-series metrics in Reports.

How candle ranges are determined

The time range each candle represents (e.g., 1 hour, 1 day, 1 week) is not fixed. Instead, it is dynamically calculated based on the following:

  • The selected date range in your report

  • The amount of data available within that range

  • The width of your browser or screen

The system automatically determines the most appropriate range to avoid overcrowding and overlapping of candles on the chart. For example:

  • A short date range with a wide screen may display 1-hour candles

  • A longer date range or a narrower screen may display 1-day or multi-day candles

Regardless of the selected date range, all candles within a single chart view will represent the same time interval.

Why multiple candles may appear for a single day

In some cases, particularly when selecting a view like “Week” or a custom 7-day range, the system may display multiple candles per day. This is expected behavior and allows for more granular insights when data density is high.

If fewer candles per day are preferred, consider adjusting the report settings:

  • Select a longer date range

  • Expand your browser window

  • Switch to a different view mode, such as line chart

View options

You can change how your data is visualized by using the “View” selector located in the lower-right corner of the chart. Switching to a line chart will show continuous data points without grouped summarization.

Tooltip details

Hovering over any candle will display:

  • The start and end time of the interval it represents

  • The average, maximum, and minimum values recorded during that time

This helps you better understand fluctuations and spot trends within a given reporting period.

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