The net worth spreadsheet template that eventually breaks

Let me tell you how almost every net worth spreadsheet is born. One Sunday you decide to be a Serious Adult and build a net worth spreadsheet from a template you found in twenty minutes flat. A column for what you own, a column for what it is worth, a grand total at the bottom that makes you feel briefly in control of your own life. It is clean and honest and entirely yours. On day one it is genuinely a great idea.

Here is the part nobody mentions when they hand you the net worth spreadsheet template. That clean little workbook does not stay clean. It rots. Not in a dramatic, smoking-laptop way, but slowly, the way a fence rots, until one day you lean on it and it gives. This post is about that day, and what to keep when it comes.

Why everyone starts with a net worth spreadsheet

The instinct is correct, so let me defend it before I tease it. A spreadsheet hands you two things at once, and they are the two that matter. The file belongs to you, so ownership is sorted. And you can see how every number was made, because every figure is a fact you typed and every total is a formula you can read, on account of being the genius who wrote it. Nobody holds your broker login. No mystery service gets to decide what your book is worth this morning. Your net worth is right there in plain sight, built from facts you trust.

For about a fortnight, this is bliss. A flat, a pension, a stocks pot, a bit of crypto, some cash, all in one tidy ledger that adds up to a single number. Anyone telling you to skip the spreadsheet and pay for software on day one is selling you something. The spreadsheet is the right tool. It just has a shelf life nobody prints on the box.

Where the template quietly rots

The trouble with a net worth spreadsheet is that net worth is not a photograph. Your template froze it on the day you built it, and the rot sets in along every line where the world keeps moving and your cells do not.

Prices go first. Your house number is whatever you guessed in 2024. Your fund prices are whatever you last typed in when you could be bothered, which was March. The total still computes with total confidence, because a cell has no shame and will report a stale figure as gospel. So your net worth is now partly real and partly a museum piece, and nothing turns red to tell you which.

The formulas crack next. You copy a row to add a holding and the SUM does not stretch to cover it. A live-price formula coughs and returns a blank, which the total three rows down cheerfully treats as a zero. None of this throws a tantrum. The book keeps adding up. It just adds up to fiction now.

And the worst of it is the stuff a single net worth figure was never built to hold. You sell half a position and your spreadsheet has no idea which tax lots you sold, so your cost basis becomes a guess wearing a tie. Hold the same fund in a taxable account and a pension and a flat template averages them into one blob, right when FIFO says they must stay separate and ordered. A dividend lands. A stock splits. A currency moves. Each one is an event your sheet needed to be told about by hand, and the one time you forget, the rot spreads one cell further.

The maintenance tax nobody warned you about

Here is the bill that arrives in instalments. To keep a net worth spreadsheet honest, you have to become its calculation engine. You re-key the prices, patch the broken SUM, adjust for the split, re-type the exchange rate you forgot about in March. Every weekend, in little dribbles of admin, you do the work the template cannot do itself.

Notice what that work does as the book grows. It grows with it. Two holdings is a five-minute chore. Forty holdings across six accounts in three currencies is a part-time job you did not apply for and cannot quit without binning the record. And here is the cruel twist. Every manual touch is a fresh chance to fat-finger a silent error into the exact book you keep in order to feel safe. So the maintenance tax costs you more than hours. It bleeds trust out of the record one keystroke at a time. The spreadsheet is also only one of several things you end up nursing, as the DIY investor tool stack lays out.

The tell that your spreadsheet has rotted

You will know the exact day. It is the day you open the workbook, see the number at the bottom, and instead of nodding you think, hmm, let me check that against my statements first. That is the moment the spreadsheet stopped being an asset and became a rumour. Once a book needs double-checking it has quietly stopped being a book.

The usual advice at this point is to surrender. You hand the whole thing to an app that links your accounts, lets a robot sign in as you, and serves you a feed you cannot audit. People call that an upgrade. What it actually does is swap a rumour you wrote for a rumour a stranger wrote, and a scraped book breaks silently too. The portfolio spreadsheet versus app piece has the long version. The short one is this: you loved the spreadsheet because you owned it, and linking throws that away.

Keep the ledger. Let the maths take care of itself.

So here is the option nobody put on the menu. The rot in a net worth spreadsheet was never hiding in the part you actually do. It lived in the part the spreadsheet quietly made you do. Typing the facts of your financial life keeps the book yours and reconcilable, and that bit is fine. Re-keying stale prices every weekend is the rotting part. Keep the first, bin the second.

That is the whole idea Strata is built on. You keep the ledger and type the same facts you were typing into the template: what you bought, when, in which account. Everything downstream is derived from that one reconciled book. You get live valuation from public market data, so no figure ends up a 2024 fossil. FIFO tax lots keep the same fund in two accounts as two honest lots instead of one blurred average. Realised profit and loss lands as you log your sells, and there is a forecast of the dividends headed your way. Splits and dividends become events you log once rather than formulas you patch forever, and when you slip, the mistake gets voided and kept in the history rather than silently overwritten. The book does not rot as it grows, because nobody is hand-cranking the maths to keep it alive. For how this stacks up across the category, the buyer’s guide to portfolio trackers is honest about the trade-offs.

Your net worth spreadsheet was a good first instinct and it served you well. Keep the instinct, keep the ownership, and stop paying the maintenance tax on a template that was always going to break. You can build your portfolio on a ledger you own that does the rotting parts for you, and let the old workbook retire with dignity.