Excel uses many different units for measuring different things, and FlexCel uses the same.

For most rendering stuff, including the PDF API, FlexCel uses points, and those is simple: A point is 1/72 of an inch. As you can see in the google calculator here.

A point is also normally used to specify font sizes: For example a font with 10 points has a bounding box of 10/72 inches.

Now, the Excel units are a little more complex. The simplest ones are the y coordinates (rows): A row is measured in 1/20 of an inch. From: https://download.tmssoftware.com/flexcel/hlp/vcl/index.htm?FlexCel.Core.TExcelFile.GetRowHeight(Int32).htm Returns the current Row height, in Excel internal units. (1/20th of a point)

But the x coordinates (columns) are way more complex. They measure how many “0” you can put in a cell in the font used in the “Normal” style, plus some margins. So, for example, the normal style for an Excel 2007 or newer file is “Calibri 11”, so if you can fit 5 “0”s in a column with that font, (“00000”) then the column width is 5. But not exactly, there are some margins too, which aren’t correctly documented in Excel docs, and which actually change depending in the screen resolution. So the width is not going to be 5, but 5.something. As explained in the help on GetColWidth ( https://download.tmssoftware.com/flexcel/hlp/vcl/index.htm?FlexCel.Core.TExcelFile.GetColWidth(Int32).htm ) you can convert between columns and rows and pixels using ExcelMetrics.ColMult and ExcelMetrics.RowMult. I wish I could tell you this is an exact science, but sadly Excel isn’t very exact about this. You can see it simply by pressing a screen preview and measuring the real width of a cell, and compare it with what you see on the screen, you’ll see it is not exactly the same.

The actual box width for a cell can also change if you use a different screen scaling: They will look different if you use say 100% or 175% screen scaling. FlexCel can offset this with the property TExcelFile.ScreenScaling ( https://download.tmssoftware.com/flexcel/hlp/vcl/index.htm?FlexCel.Core.TFlxConsts.RowMult.htm ). While by default this is 100, if you are working always in a different setting, changing this property will make FlexCel work as if it was Excel showing the file at that particular screen scaling. Changes are not much, but they exist so in general it is a bad idea to try to do “pixel perfect” designs in Excel. You always need ot leave some room because in different resolutions the cells might be slightly smaller or bigger.

For more info about how Excel units can change with the resolution, you can also read page 14 of https://download.tmssoftware.com/flexcel/docs/vcl/UsingFlexCelAPI.pdf (Autofitting Rows and Columns)