I am trying to fit a WPF RichTextBox to exactly accommodate a grid of characters in a particular monospace font. I am currently using FormattedText to determine the width and height of my RichTextBox, but the measurements it is providing me with are too small--specifically two characters in width too small. Is there a better way to perform this task? This does not seem to be an appropriate way to determine the size of my control. RichTextBox rtb; rtb = new RichTextBox(); FontFamily fontFamily = new FontFamily("Consolas"); double fontSize = 16; char standardizationCharacter = 'X'; String standardizationLine = ""; for(long loop = 0; loop < columns; loop ++) { standardizationLine += standardizationCharacter; } standardizationLine += Environment.NewLine; String standardizationString = ""; for(long loop = 0; loop < rows; loop ++) { standardizationString += standardizationLine; } Typeface typeface = new Typeface(fontFamily, FontStyles.Normal, FontWeights.Normal, FontStretches.Normal); FormattedText formattedText = new FormattedText(standardizationString, CultureInfo.CurrentCulture, FlowDirection.LeftToRight, typeface, fontSize, Brushes.Black); rtb.Width = formattedText.Width; rtb.Height = formattedText.Height;