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Heatmap Maker

Paste a wide table, such as measurements per piece of equipment and time slot, and each cell is colored from blue (low) to red (high). Rows with the same name are averaged.

1Data Table

Paste a table copied from Excel into a cell (Ctrl+V). Click a column header (A, B…) before pasting to use the first line as column names. Double-click a header to rename it, right-click to insert/delete rows and columns, and formulas such as =A1*2 work too.

2Heatmap Options

Select the value columns. The selected column names become the X-axis categories (e.g. select '08:00', '12:00', ... in order):

How to make a heatmap

  1. Copy the row-name column (e.g. equipment) and the value columns (e.g. 08:00, 12:00, ...) together with the header.
  2. Click the column header (A) in the data table and paste - the first line becomes the column name. You can also open a CSV or Excel file.
  3. Choose the Y-axis (row) category column and tick the value columns for the X axis in the order you want. Optionally enter an X-axis name and a color bar name.
  4. Press Draw and check the cell colors and values and the highest/lowest cell interpretation.

What is a heatmap?

A heatmap turns each cell of a table into a color intensity. Without reading every number you can immediately see which row-column combinations are high or low and whether there is a pattern.

Colors run from blue (low) through yellow to red (high) (reversed RdYlBu), and each cell also shows its value to two decimal places.

Data layout

Use a wide table where each row is one subject (e.g. Equipment A) and several columns are intervals of the same measurement (e.g. time slots). The ticked column names become the X-axis cells, placed from left to right in the order you ticked them.

When the same row name appears several times (e.g. repeated daily measurements), the cell value is their mean. Cells without values are left blank.

How to read a heatmap

  • The automatic interpretation reports the position (row/column) and value of the highest and lowest cells.
  • If a whole row is red, that subject (equipment) is the likely cause; if a whole column is red, that interval (time slot) is.
  • The color bar spans the data minimum to maximum, so small differences can look like big color changes - check the values in the cells too.

Frequently asked questions

Is this a correlation heatmap?

No. It shows a table of actual values as colors. Correlation matrices between variables are available in the statistics menu of the Qstat desktop program.

How is the X-axis order set?

Columns are placed in the order you tick them. To reorder, untick them and tick them again in the order you want.

What appears when I hover?

The X-axis name, row name and value of the cell under the cursor.

Is my data sent to a server?

No. Everything is processed inside your browser and nothing is transmitted or stored.

Other chart tools

3D Surface Plot MakerDraw table data like a heatmap as a 3D surface with real height.Contour Plot MakerShow how Z is distributed over X and Y with color bands and contour lines.Bar Chart MakerCompare values by category with vertical, horizontal, grouped or stacked bars.

Need process capability, control charts or DOE?

The Qstat desktop program offers about 250 analysis features: histograms and box plots plus process capability (Cp, Cpk), control charts, measurement system analysis (MSA), design of experiments (DOE), regression and machine learning.

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