Tools · Finance
Expense tracker
Log a spend in two seconds and watch the month take shape — totals by category, a budget bar, and an honest projection of where the month lands at your current pace. No bank logins, no sign-up: your spending stays in your browser unless you choose to sync it.
How do you calculate monthly expenses?
Monthly expenses are calculated by adding every expense logged in the month, then dividing that total by the days elapsed to get a daily rate, then multiplying the daily rate by the number of days in the month to project where the month lands. A month-to-date total answers what you have spent; the projection answers whether the rate you are spending at is one the month can afford.
Daily rate = spend so far ÷ days elapsed
Projected total = daily rate × days in the month
Budget gap = projected total − monthly budget- spend so far
- Every expense dated inside the month, added up — including the ones already paid and forgotten
- days elapsed
- Today’s date within the month. Not the days you happened to log something on: a day you spent nothing is still a day that passed
- days in the month
- 28, 29, 30 or 31 — a February projection and an August projection are not the same arithmetic
- projected total
- Where the month ends if the current rate holds. A straight-line estimate of current behaviour, not a forecast
- budget gap
- Positive means the current rate overshoots the budget; negative means it lands inside it
Two things break this arithmetic, and both are worth knowing rather than hiding. A large fixed payment early in the month — rent on the 1st, an annual insurance premium — inflates the daily rate and makes the projection look alarming for a fortnight; that is why the tracker keeps the projection hidden until day 3 and why the figure settles downward as the month goes on. The mirror case is a bill that has not landed yet: the projection cannot know about it, so a month that looks comfortable on the 20th can still be beaten by one invoice on the 28th.
Because of that, the projection is best read as a direction rather than a number. Comparing it with your budget is the useful move — over pace on the 10th leaves twenty days to correct, which is the whole reason for computing it before the month is over rather than after.
A worked example: the pace projection
The projection answers “if I keep going like this, where does the month end up?” It is a straight-line estimate — spend so far, scaled to the length of the month:
Projected total = spend so far ÷ days elapsed × days in the month.
Say it’s day 10 of a 30-day month and you’ve logged $450. The pace is $450 ÷ 10 × 30 = $1,350. With a $1,200 budget, that’s $150 over pace — a nudge to ease off, ten days before the month is decided rather than after.
It shows from day 3, so a single big early purchase doesn’t throw the estimate. It is a projection of current behaviour, not a prediction — a quiet week pulls it straight back down.
Questions people actually ask
- How is this different from budgeting apps?
- The big apps want your bank login so they can auto-import transactions — powerful, but it means a company holding your credentials and your full transaction history. This tracker takes the other trade: you log each spend yourself in about two seconds, and in exchange your financial life stays in your browser. Manual logging is also the point for many people — the act of typing it is what makes the spending conscious.
- What does "on pace for" mean?
- Your spend so far divided by days elapsed, times the days in the month — where the month lands if you keep this rate. It is honest arithmetic, not a forecast: a rent payment on the 1st inflates the early pace, which is also why the projection stays hidden until day 3. Judge it against your budget, not to the cent.
- Can I set a budget?
- One monthly budget for total spend, with a progress bar that turns red past the line and a pace warning when the projection overshoots it. Deliberately one number rather than per-category envelopes — a budget you actually check beats a spreadsheet you abandon in week two.
- Is my spending data private?
- By default it never leaves your browser — no server, no analytics on your amounts, nothing to breach. Sign in with Google and it is backed up to your private account row so your phone and laptop share one ledger; you can export or delete everything from My profile.
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