How much can I spend today?
A monthly budget tells you what you may spend in thirty days. It never tells you what you may spend at lunch. Put your numbers in below and get a safe daily amount for the rest of this month — plus a 50/30/20 check on how your income is really split.
The maths behind a daily allowance
Three numbers decide what you can spend today. Income is what actually lands in the account. Commitments are the amounts that leave whether you get out of bed or not — rent, utilities, school fees, loan instalments, insurance, subscriptions. Savings is the part you refuse to touch. Whatever survives all three is the only money that is genuinely yours to spend, and it has to last until payday.
remaining = free to spend − already spent this month
today = remaining ÷ days left in the month
The last line is the one that changes behaviour. A monthly figure is too large to compare against a decision in front of you; nobody standing in a supermarket can tell whether one basket fits inside a thirty-day number. A daily figure is small enough to hold in your head and it is the same unit as the decision.
Why it recalculates every day
Overspend on Tuesday and the allowance does not shout at you. It divides what is left by the days that remain, so Wednesday's number is simply a little smaller. The correction is automatic and proportionate, which is the reason people stay with a daily figure long after they abandon a spreadsheet.
Where the 50/30/20 rule fits
The rule says roughly half of after-tax income goes to needs, about a third to wants, and a fifth to savings. Treat it as a mirror rather than a target. The bars above compare your real split with it, and the honest use of that comparison is diagnosis: if commitments have crept past half your income, no amount of daily discipline fixes it, because the problem is the size of the fixed block and not the coffee.
Households are where daily budgets break
One person with one allowance is straightforward. A family is not. Everyone spends from the same pot but each person only sees their own share of it, so the number in anyone's head is wrong by the end of the first week. This is the specific problem EXPENDR was built for: one shared household total, and when one person spends, everyone else's daily figure updates on their own phone.
This number, every morning, for the whole family
EXPENDR keeps the calculation running for a shared household budget. Add an expense and everyone's safe-to-spend updates in real time. Weekly budgets, budget alerts and the weekly recap are free. English and Arabic, 55 currencies.