r1c1

R1C1 is a cell reference style used in spreadsheet software that identifies cells by their row and column numbers rather than by a letter and number. In this system the top-left cell is R1C1; the cell in row 3, column 2 is R3C2. By contrast, the common A1 reference style uses letters for columns (A, B, C) and numbers for rows.

References can be absolute, referring to fixed coordinates, or relative to the position of the formula. In R1C1 style, absolute coordinates are written without brackets, for example R5C7 refers to row 5, column 7. Relative addresses use square-bracket offsets from the current cell, such as R[-1]C[0] for the cell one row above in the same column, or R[2]C[3] for the cell two rows down and three columns to the right. The current cell can be referred to as RC, and a left neighbor as RC[-1].

Support: Microsoft Excel offers an option to switch between R1C1 and A1 reference styles in the options menu (Formulas section). When activated, formulas in the sheet use R-style notation. Google Sheets and most other popular spreadsheet programs primarily use A1 style.

Usage: R1C1 can ease programmatic formula generation and macro writing, because coordinates do not rely on column labels. It can also reduce confusion when performing relative calculations; however, it is less intuitive for many users and can cause compatibility issues when sharing sheets with others who use A1 style.

Notes: The style uses one-based indexing, meaning row and column numbers start at 1. R1C1 notation is largely a matter of preference and context, and many teams choose a single convention for consistency.