Thursday, August 6, 2009

recalculate values after editing a cell

To use formulas efficiently, there are three important considerations you need to understand:

Calculation is the process of computing formulas and then displaying the results as values in the cells that contain the formulas. To avoid unnecessary calculations, Microsoft Office Excel automatically recalculates formulas only when the cells that the formula depends on have changed. This is the default behavior when you first open a workbook and when you are editing a workbook. However, you can control when and how Excel recalculates formulas.

Iteration is the repeated recalculation of a worksheet until a specific numeric condition is met. Excel cannot automatically calculate a formula that refers to the cell — either directly or indirectly — that contains the formula. This is called a circular reference. If a formula refers back to one of its own cells, you must determine how many times the formula should recalculate. Circular references can iterate indefinitely. However, you can control the the maximum number of iterations and the amount of acceptable change.

Precision is a measure of the degree of accuracy for a calculation. Excel stores and calculates with 15 significant digits of precision. However, you can change the precision of calculations so that Excel uses the displayed value instead of the stored value when it recalculates formulas.

Replace a formula with its result

You can convert the contents of a cell that contains a formula so that the calculated value replaces the formula. If you want to freeze only part of a formula, you can replace only the part you don't want to recalculate. Replacing a formula with its result can be helpful if there are many or complex formulas in the workbook and you want to improve performance by creating static data.

You can convert formulas to their values on either a cell-by-cell basis or convert an entire range at once.

Important Make sure you examine the impact of replacing a formula with its results, especially if the formulas reference other cells that contain formulas. It's a good idea to make a copy of the workbook before replacing a formula with its results.

Replace formulas with their calculated values

Caution When you replace formulas with their values, Microsoft Office Excel permanently removes the formulas. If you accidentally replace a formula with a value and want to restore the formula, click Undo Button image immediately after you enter or paste the value.

  1. Select the cell or range of cells that contains the formulas.

    If the formula is an array formula (array formula: A formula that performs multiple calculations on one or more sets of values, and then returns either a single result or multiple results. Array formulas are enclosed between braces { } and are entered by pressing CTRL+SHIFT+ENTER.), select the range that contains the array formula.

    ShowHow to select a range that contains the array formula

    1. Click a cell in the array formula.
    2. On the Home tab, in the Editing group, click Find & Select, and then click Go To.
    3. Click Special.
    4. Click Current array.
  2. Click Copy Button image.
  3. Click Paste Button image .
  4. Click the arrow next to Paste Options Button image, and then click Values Only.

The following example shows a formula in cell D2 that multiplies cells A2, B2, and a discount derived from C2 to calculate an invoice amount for a sale. To copy the actual value instead of the formula from the cell to another worksheet or workbook, you can convert the formula in its cell to its value by doing the following:

  1. Press F2 to edit the cell.
  2. Press F9, and then press ENTER.

    The formula is shown in the formula bar

    After you convert the cell from a formula to a value, the value appears as 1932.322 in the formula bar. Note that 1932.322 is the actual calculated value, and 1932.32 is the value displayed in the cell in a currency format.

    The value is shown in the formula bar

    Tip When you are editing a cell that contains a formula, you can press F9 to permanently replace the formula with its calculated value.

Replace part of a formula with its calculated value

There may be times when you want to replace only a part of a formula with its calculated value. For example, you want to lock in the value that is used as a down payment for a car loan. That down payment was calculated based on a percentage of the borrower's annual income. For the time being, that income amount won't change, so you want to lock the down payment in a formula that calculates a payment based on various loan amounts.

Caution When you replace a part of a formula with its value, that part of the formula cannot be restored.

  1. Click the cell that contains the formula.
  2. In the formula bar (formula bar: A bar at the top of the Excel window that you use to enter or edit values or formulas in cells or charts. Displays the constant value or formula stored in the active cell.) Formula bar, select the portion of the formula that you want to replace with its calculated value. When you select the part of the formula that you want to replace, make sure that you include the entire operand (operand: Items on either side of an operator in a formula. In Excel, operands can be values, cell references, names, labels, and functions.). For example, if you select a function, you must select the entire function name, the opening parenthesis, the arguments (argument: The values that a function uses to perform operations or calculations. The type of argument a function uses is specific to the function. Common arguments that are used within functions include numbers, text, cell references, and names.), and the closing parenthesis.
  3. To calculate the selected portion, press F9.
  4. To replace the selected portion of the formula with its calculated value, press ENTER.

    If the formula is an array formula (array formula: A formula that performs multiple calculations on one or more sets of values, and then returns either a single result or multiple results. Array formulas are enclosed between braces { } and are entered by pressing CTRL+SHIFT+ENTER.), press CTRL+SHIFT+ENTER.

http://office.microsoft.com/en-gb/excel/HP100541491033.aspx

http://office.microsoft.com/en-gb/excel/HP100662581033.aspx?pid=CH100648421033#Replace%20a%20formula%20with%20its%20calculated%20value

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