Most budgets are monthly because bank statements are monthly. That is the whole reason. Nobody sat down and decided that thirty days is the right span for a human being to hold a number in their head. It is just how the paperwork arrived.
The trouble is that a monthly number only becomes real at the end of the month, which is exactly when you can no longer do anything about it. A $700 grocery budget is abstract on the 3rd, vaguely worrying on the 18th, and a fact on the 30th.
I built Buoy around a different unit of time, and I want to walk through why.
The number you can hold in your head
Take that $700 grocery budget and divide it by the days in the month. In a 30-day month that is $23.33 a day. Round it to whatever you like; the point is that it is small enough to remember and to compare with what is in your hand at the register.
Now the budget answers a question you ask every day. “How am I doing this month?” becomes “can I get the nicer olive oil today?” If you have not spent anything for three days, the answer is yes, with room to spare. If you did a big shop yesterday, you know that too.
That is the entire idea behind a daily allowance. Same money, same month, a different resolution.
Counting up instead of counting down
Here is where Buoy departs from the envelope apps. Instead of showing you a shrinking pile, each category earns its allowance every day and the balance grows when you do not spend it.
Day 1, groceries starts at $23.33. Day 2, with no shopping, it reads $46.66. You buy $40 of food on day 3 and it dips to $30, then keeps climbing from there. The number you see is what you have kept, not what you have lost.
That sounds cosmetic. Watching a number go up feels different from watching one go down, and it is the difference between a budget you check because you want to and one you avoid because it makes you feel bad. The people who quit budgeting apps mostly quit for the second reason. I did.
How the allowance is computed
For the technically curious, this is what happens under the hood.
Each count-up category stores a daily allowance rather than a monthly cap. When you set a category to $700 a month, Buoy converts it to a per-day figure for the current month and recomputes it at the boundary, so a 31-day month and a 28-day month both land on the monthly figure you asked for.
Every transaction that syncs from your bank is categorized (by a rule you wrote, by what the bank says, or by the AI when neither is sure) and subtracted from that category’s accrued balance. The balance you see at any moment is:
(daily allowance x days elapsed this period) - spent this period + rolloverRollover is the part people ask about. If you end a month with money left in a category, you can carry it forward, so a good August makes September easier. If you overspend, the debt carries forward too, which is honest, and the app lets you clear it deliberately rather than pretending it did not happen.
None of this needs manual entry. Transactions arrive through the bank connection and the math runs itself. Your job is to glance at a number.
When a daily allowance is the wrong tool
A daily allowance is for spending that happens in small, frequent amounts: groceries, dining out, fuel, the shopping category that absorbs everything else. That is where the daily resolution helps.
It is a poor fit for rent, insurance, or an annual subscription, where the money leaves in one lump. For those, a plain monthly category with the amount set aside is the right shape, and Buoy lets you mix both kinds in one budget. The mistake I see most often is trying to run everything as a count-up, then wondering why the rent category looks strange on the 2nd of the month.
Where to start
Pick one category. Groceries is the classic because everyone has one and it is where the daily rhythm is most obvious. Set the monthly figure you already have in your head, let it convert to a daily allowance, and watch it for two weeks without changing anything.
You will learn more about your own spending from that fortnight than from any spreadsheet, because the number was there every time you looked at your phone, and it was going up.
Buoy has no ads and never sells your data; the subscription is what pays for it, and the trial needs no card.