How the calculator works
It uses one formula: the money you have left for flexible spending, divided by the days left in your budget period, including today.
today's limit = money left ÷ days left (including today)
The table under the result shows what happens tomorrow depending on what you spend today. Spend less than today's limit and tomorrow's number goes up; spend more and it goes down, but only a little, because the difference is shared over all the days that are left.
What to enter
- Money left for spending: your budget for day-to-day things (food, transport, coffee, shopping) minus what you have already spent this period. Leave rent, loan payments and other fixed bills out.
- Days left: count today. If today is the 10th and your last day before payday is the 24th, that is 15 days. Or simply pick the last day in the date box.
Example
You have $1,200 for flexible spending and 30 days until payday. Today's limit is $40. If you spend $25 today, tomorrow you will have $1,175 for 29 days: $40.52 a day. If you spend $70, tomorrow's limit becomes $38.97. One big day does not ruin the month; it just makes the rest of it slightly tighter.
Tips
- Check the number before you spend, not after.
- Match the period to your pay: weekly pay means a 7-day period.
- Plan known big costs in a separate savings pot so they do not crush the daily number.
Questions
Should I include rent and bills?
No. Take fixed bills out first. The daily limit is only for flexible, day-to-day spending; including bills makes the number look bigger than it really is.
What if I go over one day?
The overspend is shared over the remaining days, so each day after it gets a little less. That is the advantage of a rolling limit over a fixed daily allowance.
Does this calculator save my numbers?
No. It runs entirely in your browser. Nothing you type is sent to a server or stored.
Can I use it for a weekly budget?
Yes. Enter the money left for the week and the days left in the week.
Want the method behind it? Read: How to set a daily spending limit that adjusts as you go
Read the guideResults are estimates for planning. They are not financial advice. Check important numbers before you rely on them.