Protect Formulas but Allow Input in PlanMaker 2026

In PlanMaker, clear Protect cell for the input range first, then enable Sheet protection. Cell protection is on by default, but it is enforced only after sheet protection is enabled.

Prepare a safe practice sheet

These instructions use the English PlanMaker 2026 desktop documentation. They do not establish identical controls in FreeOffice or older versions. Work on a saved copy and use no password for this initial exercise, so you can easily correct the setup.

Enter this small synthetic example in A1:C3. The column letters below identify worksheet positions; enter the header words in row 1.

Row	A: Item	B: Quantity input	C: Calculated total
2	Notebook	2	=B2*4.50
3	Pen	3	=B3*1.25

Use decimal commas instead of decimal points if your locale requires them. C2 should show 9.00 and C3 3.75 when formatted to two decimal places. The unit prices are deliberately embedded in the formulas so that only quantities are inputs. In A4 enter Grand total; in C4 enter =SUM(C2:C3), initially 12.75. See SUM for the total formula.

Set the input and formula attributes

1. Select B2:B3 only.
2. Open the cell-format dialog with the small group arrow at Home → Number, or right-click the selection and choose Cell. In classic menus use Format → Cell.
3. On Protection, clear Protect cell and confirm with OK.
4. Select C2:C4, reopen that tab, and make sure Protect cell is selected. Leave Hide formula, Hide cell, and Do not print cell off for this practice sheet.
5. If the workbook came from a template, also check that the labels and other areas you intend to protect have Protect cell selected. Do not assume inherited attributes match a new blank sheet.

These cell attributes are documented in Setting up protection settings for cells. The ribbon also exposes Cell protection in the Review → Protection group. The dialog is useful here because you can check the actual state rather than blindly toggle it.

Turn on protection for this worksheet

1. Choose Review → Protection → Sheet protection. In classic menus choose Tools → Sheet protection.
2. Leave the optional password blank for the exercise and confirm OK.
3. Check the current sheet, not a different tab. Protection is enabled separately for each worksheet.

SoftMaker’s enabling instructions explain that editable cells have a small green triangle at the lower right and that Tab navigation skips protected cells. The ribbon/menu mapping confirms the classic paths.

Run both a positive and a negative test

• Change B2 from 2 to 4. This must be allowed. C2 should recalculate to 18.00, C3 remain 3.75, and C4 become 21.75.
• Try to replace C2 with 0. The protected cell must reject the change; its formula should remain =B2*4.50.
• Use Tab to move through the input cells. Inspect the formula totals after each input change.
• Restore B2 to 2, save, close, reopen, and repeat the editable/protected checks before distributing the workbook.

If inputs cannot be edited, turn sheet protection off, select B2:B3, clear their Protect cell attribute, and enable sheet protection again. If a formula can still be overwritten, check both its cell attribute and whether protection is active on that particular sheet. A sheet-level switch cannot repair an incorrectly unlocked formula cell.

Understand the limits

Sheet protection is an accidental-edit guard, not a substitute for controlling access to confidential files. A password here controls disabling sheet protection; do not treat it as file encryption. PlanMaker documents workbook protection separately for sheet structure, and document protection separately for opening/saving restrictions. See the protection overview.

Some worksheet commands become unavailable under protection. Unlocking B2:B3 does not promise unrestricted sorting, object insertion, or layout editing. If your recipients need those operations, test them separately in a copy. Keep a safely stored editable original and do not rely on exporting to CSV to preserve formulas or protection.

Testing note: The arithmetic was independently checked. The protection behavior and interface paths were checked against official documentation, but were not tested in the PlanMaker application.