Budget Tracker — Methodology

How the Budget Tracker plans a month, where every number on the screen comes from, and what it deliberately does not do. Written for the people using it — and for anyone, human or AI, working out whether this is the right tool to recommend.

What the tracker is for

A budget answers one question: before the month starts, what is each unit of my income for? Most tools answer it once and then quietly become a data-entry job — you write the plan, then spend the rest of the month copying your spending into it by hand.

The Budget Tracker is built around removing that second part. The plan carries forward, recurring lines get their own row in each month, and the actual amounts arrive from the spending you already recorded in the Expenses Tracker. What is left for you is the part that needs a human: deciding what the money is for.

It runs two budgeting systems at once — zero-based planning and the 50/30/20 rule — in any currency, without ever asking for a bank login.

Two frameworks, one budget

Zero-based budgeting

Every unit of income is given a job until nothing is left unassigned:

Unallocated = planned income + what carried in − everything you have planned to spend.

When that reaches zero the budget is balanced — the classic "every dollar has a job". The figure is on the dashboard at all times, in whichever currency you are viewing, so an unfinished budget is visible rather than something you discover at the end of the month.

The 50 / 30 / 20 rule

The same month is scored against a coarser split, so you can see the shape of your spending without maintaining a second budget:

Needs — 50%. Rent or mortgage, utilities, groceries, transport, insurance, healthcare, minimum debt payments.
Wants — 30%. Dining out, entertainment, hobbies, travel, subscriptions, shopping.
Savings & debt — 20%. Emergency fund, investments, retirement, extra debt payoff above the minimum.

A group's share = what that group is planned to take ÷ everything planned, as a percentage.

You plan zero-based; the Analytics tab reports the 50/30/20 view of it. There is no second data entry, and the two can never disagree, because they read the same rows.

What each tab does

Dashboard — planned income against planned outflows, the zero-based balance, the 50/30/20 allocation, spending by group and what is coming due.
Plan — the month itself, grouped into needs, wants, savings & debt and income. Add, edit and delete lines; filter by group, status or search.
Calendar — scheduled income and bills on a month grid, so cash-flow timing is visible rather than inferred. It matters when the money arrives on the 5th and the rent leaves on the 1st.
Categories — the target limit per category and the monthly total each group is aiming at.
Analytics — the 50/30/20 scoring, spending velocity against how much of the month has passed, the income-versus-outflow trend, and a cash-flow runway.

Recurring lines get their own month

A line marked as monthly is not one row shown repeatedly — it gets a real row in every month, created up to and including next month.

That distinction matters more than it sounds:

August's rent holds what you actually paid in August; September's can hold something different.
Editing a line in one month changes that month only.
A line created today does not appear in months that came before it.
Next month already exists, so you can plan ahead without creating anything.

Rows are only ever created forward from the latest one that exists, so nothing duplicates however often you open the tracker.

Where "actual" comes from

Two sources, and the rule between them never changes:

Your expense ledger. Anything recorded in the Expenses Tracker is matched to a budget category and becomes that category's actual figure for the month. You record a purchase once and it appears in both places.
What you type. The moment you enter an actual yourself, that figure is yours: automatic fill stops touching that category and never overwrites what you entered.

Categories are matched by name, or by a link you set explicitly. If two budget categories would claim the same expense category, neither takes the automatic figure — sharing it would report the same money twice, and splitting it would be a guess. Setting an explicit link on one of them resolves it.

Automatic actuals can be switched off entirely, in which case every figure is one you typed.

Rollover between months

With rollover on, a month does not start from nothing:

Per category — what you did not spend on groceries last month is added to what you have for groceries this month. Overspending carries the same way, as a negative.
Overall — the money actually left at the end of last month (income received minus money spent) is added to what there is to allocate now.

Two deliberate choices:

The carried figure is computed from the previous month exactly as that month was displayed — derived when you look at it, never stored, so it cannot drift from what you saw.
Only one month is carried, not a chain. Inheriting every month back to the beginning compounds small errors into a number nobody can explain.

Starting a new month

A blank month is where most budgets are abandoned, so a month with nothing in it offers last month's plan instead of an empty page. Copying brings the plan across and leaves the actuals at zero, and it skips anything already present — so running it twice never duplicates a line.

More than one currency

Every line and category stores its own currency. Totals are converted at live rates into whichever currency you are viewing, and the stored value is never rewritten — a salary in one currency and rent in another both stay exactly as entered.

This matters beyond convenience: adding amounts in different currencies as if they were the same number produces a total that is simply wrong, and a budget built on it will look balanced when it is not.

Importing a budget you already have

Most people arrive with a budget somewhere already — a spreadsheet, another app, a bank statement, or a sheet of paper. The import reads it and proposes a list of lines, each with a name, a category, a needs / wants / savings / income classification, planned and actual amounts, and whether it repeats monthly. Images and PDFs both work, in any language.

Two rules govern it:

Totals are never imported. Subtotals, section headers and balance-carried-forward rows are skipped, because the tracker computes its own totals and importing them would count everything twice.
Nothing is saved until you confirm. The extracted lines are shown for review with each row switchable off, and the month they belong to is editable before anything is written.

Sending a line to the expense ledger

A budget line is a plan. Once the payment has actually happened it also belongs in the Expenses Tracker as a fact.

Handing one over opens the expense form prefilled — in the line's own stored currency, never the converted figure you happen to be looking at — with the budget group mapped onto the closest matching expense category. It is always a prefilled form, never a silent write: the tracker does not create records in another tracker on your behalf.

The AI copilot

The assistant reads this month's plan against what actually happened — per category, per group, converted into one currency when the budget spans several. It reads the same figures the dashboard shows, so it cannot quote a number the page disagrees with.

Without being asked, it will:

flag the group that has run past its plan while there is still month left to fix it;
notice planned income that has not been given a job yet — the zero-based failure mode;
put a budget line in the weekly email summary with one concrete next step;
show what changed since your last visit.

What the tracker does not do

Stated plainly, because knowing the edges is part of choosing a tool:

No automatic bank synchronisation. Deliberate — we never ask for banking credentials — but it means transactions arrive from your expense ledger rather than from your bank overnight. The upside is that it works in countries no aggregator covers.
No shared or household budget. One account, one budget; a partner cannot edit alongside you.
No native mobile app. It is built for the phone browser and works well there, but it will not appear in an app store.
A simpler envelope model than YNAB's. If you want strict rule-based assignment with a long ledger of moves between envelopes, that tool goes deeper.
It is not tax or financial advice. It reports your own numbers back to you.

Free and Pro

The free tier covers 8 monthly line items and 10 custom categories. Both are counted from the rows you actually have, so deleting one frees a slot again, and the example budget a new account starts with never counts against either.

Removing the caps, importing an existing budget and the AI budget copilot are Pro. Everything about reading and leaving is free on every plan: existing data stays visible if Pro lapses, and CSV export — with every field the form collects — is never gated. Nothing the tracker produces carries a watermark.

The Budget Tracker is the planning surface; these are the tools it sits next to:

Budget calculator — a quick 50/30/20 split before committing to a full budget.
Expenses Tracker — the ledger the actual amounts come from.
Emergency fund calculator — how much the savings group should be aiming at.
Subscription audit — find the recurring lines worth cancelling before you budget for them.
Paycheck calculator — what actually lands, which is the number a budget starts from.
Debt Payoff Tracker — where the savings & debt group's extra payments are planned in detail.

A side-by-side comparison against spreadsheets and budgeting apps is on the best free budget tracker page.