Start by putting everything on the same footing
Income and bills rarely all arrive on the same schedule. You might be paid monthly, pay rent weekly, and pay a subscription every four weeks. Comparing these directly is misleading, so the first step is converting everything to the same period, usually monthly.
Convert properly, not just "divide by 4"
A common mistake is treating a weekly amount as if multiplying it by 4 gives a monthly figure. It doesn't. Most months have slightly more than four weeks in them. The more accurate approach is to convert every amount to an annual total first, then divide by 12:
- Weekly amount × 52 = annual total
- Fortnightly amount × 26 = annual total
- Four-weekly amount × 13 = annual total
- Monthly amount × 12 = annual total
Add up all your annual totals, then divide by 12 for a genuine monthly figure, or by 52 for a genuine weekly one. This is the same normalisation rule the Budget Planner uses internally, so a figure you work out by hand should match what the calculator shows.
A simple worked example
Say your take-home pay is £2,400 a month, your rent is £150 a week, and a subscription costs £20 every four weeks. Converted to annual totals: £2,400 × 12 = £28,800 income; £150 × 52 = £7,800 rent; £20 × 13 = £260 subscription. Dividing the annual totals by 12 gives a genuine monthly view: £2,400 income, £650 rent, about £21.67 for the subscription. These are figures you can now compare directly and add up correctly.
Group your regular spending
Once everything is on a monthly footing, grouping it into categories, such as housing, household bills, food and essentials, transport, and anything else regular, makes it easier to see where your money actually goes, rather than working from a single unsorted list.
What this kind of budget doesn't do
This is a way of organising and understanding your own numbers. It doesn't tell you whether a particular level of spending is "good" or "bad", it doesn't prioritise debts or recommend a repayment order, and it doesn't assess mortgage affordability or recommend any financial product. Those are separate questions from simply seeing where your money currently goes.
Do the maths automatically
The Budget Planner applies this same conversion automatically across as many income and expense lines as you need, at whatever frequency each one actually occurs, and shows your estimated monthly surplus or shortfall. Every figure you enter stays in your browser. See Privacy for detail.