Protecting cells · Code with Martin

Everything is editable — until you say no

In a spreadsheet you can click anywhere and type. That is a trap: a neighbour deletes a heading, you overwrite an average formula. Protection locks cells. Without a password (or with permission) you cannot type into them.

In Sheets: Data → Protected sheets and ranges.

💡

First you unlock everything, then you select cells you may type into, and you lock the rest. Or you lock only the row with a formula. Today a simple version: protect row 1.

Lock the heading

Sheet Grades. Data → Protected sheets and ranges → Add a sheet or range.
Range 1:1 (the whole of row 1) or A1:B1.
Description: Headings. Set that only you may edit (or nobody except you — depending on the dialog).
Done. Try typing into A1 — Sheets warns or will not let you.

Data from row 2 you still edit as normal.

⚠️

Protection is not a password for the whole world. Who has edit rights on the workbook can turn protection off. It is a safety net against a mistake, not a vault. For handing in to a teacher, sharing “view” is enough.

A warning when editing

When you edit a protected cell, Sheets shows a dialog. Cancel = nothing changes. Continue = sometimes it goes, when you are the owner of the protection.

In Excel: Review → Protect Sheet. A similar idea.

What to protect in the course

What	Why
Row 1 headings	So Subject/Grade stays
Cells with an average formula	So `=AVERAGE(...)` stays
A sheet with a finished project	A friend in a shared workbook

Leave grades in B2:B10 unlocked — those change.

Remove protection

Data → Protected sheets and ranges → by the range a bin icon or a pencil → delete protection. If you forget what is locked, try typing — the warning will tell you the range.

🏫 Grade average

One sheet, two columns: subject and grade. At the bottom a sum and an average.

💰 Pocket money

Rows = days, columns = income / spend / left.

📊 Class survey

One question, answers in one column, later a chart.

🏆 Mini dashboard

Three numbers at the top and one chart. Numbers as a link, not copied by hand.

Now you 💪

Heading Grades A1:B1 is protected (or the whole of row 1).
Into B3 you can still type a grade.
You tried typing into A1 — you got a warning or a block.
You know where to turn protection off (Data → Protected sheets and ranges).
You understand: protection ≠ sharing view only. You can combine both.

✅

Check: You know how to lock a heading against a mistake. Data under it you still change.

What to take from this lesson

A protected range will not let you edit (or it warns).
Protect headings and formulas. Not input data.
Protection is against a mistake, not against a hacker.
Data → Protected sheets and ranges manages the locks.
Sharing “view” protects with strangers. Cell protection with you.