| Interface | Description |
| IAboveAverage | Represents a conditional format for above or below average values. |
| IAreas | Represents a collection of ranges, each of which represent a single contiguous range of one or more cells. |
| IAutoFilter | Represents the autofilter options of a worksheet. |
| IBorder | Represents the color, style, and weight of a border. |
| IBorders | Represents the border color, border style, and border weight of a cell or range of cells. |
| IBuiltinDocumentProperties | Represents a collection of built-in document properties associated with a workbook. |
| ICharacters | Represents the font and text of a range of characters in a text cell or shape. |
| IChartSheet | Represents a chart sheet. |
| IChartSheets | Represents a collection of chartSheets in a workbook. |
| IChartSheetWindowInfo | Represents chart sheet specific window information. |
| IChartSheetWindowInfos | Represents a collection of IChartSheetWindowInfo instances in a chart sheet. |
| IColors | Represents the color palette of a workbook. |
| IColorScale | Represents a conditional format which uses color scales. |
| IColorScaleCriteria | Represents the collection of criteria for a conditional format which uses color scales. |
| IColorScaleCriterion | Represents an individual criterion for a conditional format which uses color scales. |
| IColorStop | Represents an individual color stop for a gradient fill. |
| IColorStops | Represents the collection of color stops for a gradient fill. |
| IComment | Represents a cell comment. |
| IComments | Represents the collection of cell comments for a worksheet. |
| IConditionValue | Represents the minimum or maximum condition value of a conditional format. |
| IDatabar | Represents a conditional format which uses data bars. |
| IDataBarBorder | Represents the border of a data bar conditional format. |
| IDialogSheet | Represents a dialog sheet in a workbook. |
| IDocumentProperties | Represents a collection of built-in or custom document properties associated with a workbook. |
| IDocumentProperty | Represents a built-in or custom document property associated with a workbook. |
| IFactory | Represents a factory which created a workbook set and all of the objects contained by the workbook set. |
| IFactoryChild | Represents an object which was directly or indirectly created by a SpreadsheetGear.IFactory . |
| IFilter | Represents an individual filter associated with a set of autofilters. |
| IFilters | Represents the collection of filters associated with the autofilter of a worksheet. |
| IFont | Represents the font of a cell, range or object. Setting the properties of an instance of IFont modifies the font properties of the represented cell, range or object. |
| IFormatColor | Represents the colors used by color scale and data bar conditional formats. |
| IFormatCondition | Represents a conditional format. |
| IFormatConditions | Represents the conditional formats associated with a range. |
| IGradient | Represents the ILinearGradient or IRectangularGradient returned by the IRange.Interior.Gradient property. |
| IHPageBreak | Represents a horizontal page break (a row page break) in a worksheet. |
| IHPageBreaks | Represents the collection of horizontal page breaks (row page breaks) in a worksheet. |
| IHyperlink | Represents a hyperlink. |
| IHyperlinks | Represents a hyperlink collection. |
| IIcon | Represents an individual icon in an icon set. |
| IIconCriteria | Represents the collection of criteria for a conditional format which uses a set of icons. |
| IIconCriterion | Represents an individual criterion for a conditional format which uses a set of icons. |
| IIconSet | Represents an icon set. |
| IIconSetCondition | Represents a conditional format which uses a set of icons. |
| IIconSets | Represents a collection of icon sets. |
| IInterior | Represents the interior of a cell, range or object. |
| ILinearGradient | Represents a linear gradient returned by the IInterior.Gradient property. |
| IModule | Represents a module. |
| IName | Represents a defined name. |
| INames | Represents the collection of defined names in a workbook or worksheet. |
| INegativeBarFormat | Represents the negative bar format of a data bar conditional format. |
| IOutline | Represents the outlining options of a worksheet. |
| IPageSetup | Represents the page setup properties of a worksheet. |
| IPane | Represents a worksheet window pane. |
| IPanes | Represents the collection of window panes associated with a worksheet. |
| IPrintable | Marks a class or interface as being printable. |
| IProtection | Represents the fine-grained protection attributes of a worksheet. |
| IRange | Represents one or more cells, rows, columns, or ranges of cells. |
| IRectangularGradient | Represents a rectangular gradient returned by the IInterior.Gradient property. |
| ISheet | The base interface of all sheets in a workbook, including worksheets, chart sheets, dialog sheets, macro sheets and VBA modules. |
| ISheets | Represents all of the sheets in a workbook, including worksheets, chart sheets, dialog sheets, macro sheets and VBA modules. |
| IStyle | Represents an individual named cell style associated with a workbook. |
| IStyles | Represents the named cell styles associated with a workbook. |
| ITab | Represents a sheet tab. |
| ITop10 | Represents a conditional format for top or bottom ranking values. |
| IUniqueValues | Represents a conditional format for duplicate or unique values. |
| IValidation | Represents the data validation associated with a range of cells. |
| IVPageBreak | Represents a vertical page break (a column page break) in a worksheet. |
| IVPageBreaks | Represents the collection of vertical page breaks (column page breaks) in a worksheet. |
| IWorkbook | Represents a workbook. |
| IWorkbooks | Represents all of the workbooks in a workbook set. |
| IWorkbookSet | Manages a set of workbooks which may refer to each other by external cell references or external defined name references. |
| IWorkbookWindowInfo | Represents workbook specific window information. |
| IWorkbookWindowInfos | Represents a collection of IWorkbookWindowInfo instances in a workbook. |
| IWorksheet | Represents a worksheet. |
| IWorksheets | Represents a collection of worksheets in a workbook. |
| IWorksheetWindowInfo | Represents worksheet specific window information. |
| IWorksheetWindowInfos | Represents a collection of IWorksheetWindowInfo instances in a worksheet. |