You know the moment. You're in the queue, about to tap your card, and you're doing sums in your head. There's £312 in the account. Payday is the 28th. But the phone bill hasn't come out yet, and neither has the car insurance, and was the gym on the 25th or the 26th?
The number on your banking app is not the answer. It's the start of a maths problem you're being asked to solve from memory, several times a day.
Here's the actual answer, and the one-line calculation behind it.
The calculation
If you want to run the calculation with your own figures, use the free payday cashflow calculator. It works in your browser without an account or bank connection.
That's it. Not your salary, not your monthly budget, not a spreadsheet with categories. Just two numbers:
- Your balance right now. Open your banking app once and note it down.
- Every bill and direct debit that will leave the account between today and payday. Rent or mortgage if it falls in that window, phone, energy, subscriptions, insurance, anything on a standing order.
Subtract the second from the first. The result is the amount left after the fixed payments you entered have been allowed for. Everything above that number is already spoken for—it just hasn't left the account yet.
A worked example
Say it's the 14th, you get paid on the 28th, and your balance is £412.
Bills still to come out before the 28th:
| Bill | Amount |
|---|---|
| Energy | £84 |
| Phone | £32 |
| Spotify | £12 |
| Car insurance | £58 |
| Total still to go out | £186 |
£412 − £186 = £226 clear to spend over the next 14 days.
Your banking app shows £412. After allowing for the £186 of fixed payments still due, your working clear-to-spend figure is £226. That £186 gap is exactly where “how did I end up in my overdraft?” can come from—the bills were always coming, they just hadn't landed when you checked.
Why per-day figures can mislead you
A tempting next step is to divide by the days remaining: £226 ÷ 14 = about £16 a day. As a rough pacing guide, fine. But treat it loosely, for two reasons.
First, spending isn't smooth. A supermarket shop or a night out lands as one lump, so a strict daily figure sets you up to feel behind on day two.
Second, division by days remaining behaves badly at the end of the cycle. With £30 left and one day to go, the maths says “£30 today”—technically true, practically an invitation to arrive at payday with nothing. The headline number to trust is the total that's clear to spend, not a per-day figure.
You may also choose to leave part of the result untouched as a buffer, rather than treating the entire figure as a spending target.
Do this once, not fourteen times
The catch with the manual method: it's only accurate at the moment you do it. Spend £40 on Friday and your number is stale. Most people respond by re-checking their banking app constantly—one number, checked eight times a day, that never actually answers the question.
This is the problem ClearTill was built for. You tell it your balance, your payday and your bills—typing them in plain English is enough, and it works out the rest. The first thing you see is a single figure: what you're clear to spend before you're paid. When you update your balance, ClearTill immediately recalculates the bills still due and your new clear-to-spend figure.
No bank connection, no transaction history, no categories to maintain. Your seven-day live preview needs no card, and nothing is charged automatically when it ends. See current ClearTill pricing if you decide to continue.
You can also read about ClearTill and GMBF Ventures Ltd.
Frequently asked questions
Should I include food and petrol as bills?
No—only fixed, dated payments that leave the account automatically. Food, fuel and everything you actively choose to buy is what the clear-to-spend figure is for. If you prefer certainty on essentials, you can set aside a fixed weekly amount for food and treat it like a bill, but keep it simple to start.
What if a bill is due on payday itself?
Count anything due before the money lands. If rent goes out on the 28th and pay arrives on the 28th, timing within the day varies by bank. It is safer to count it as due before payday so the surprise, if any, is a pleasant one.
What about money coming in before payday?
If it is certain—a refund or a transfer from a partner—add it to the balance side. If it is only probable, leave it out. The figure is most useful when it is the cautious version.