How to smooth big bills across your pay cycles
Smoothing a big bill means dividing its yearly cost by the number of times you are paid in a year, then moving that amount aside every payday so the bill is already funded when it lands. A $890 car registration becomes $34.23 a fortnight. Nothing has to be found in the week it's due, because it was never counted as spendable.
Small regular bills mostly look after themselves. It's the big irregular ones that wreck a budget: registration, insurance, the quarterly power bill, the annual excess on something. They're predictable in size and timing, and they still manage to arrive as a surprise.
The sum
Yearly cost, divided by the number of paydays in your year. Fortnightly is 26, weekly is 52, monthly is 12.
Four irregular bills, smoothed to a fortnight
- Car registration, $890 a year $34.23
- Power, $340 a quarter ($1,360 a year) $52.31
- Home and contents, $1,120 a year $43.08
- Water, $260 a quarter ($1,040 a year) $40.00
- Set aside every fortnight $169.62
- Covered across the year $4,410.00
$169.62 x 26 = $4,410.12, twelve cents over the yearly total, which is rounding. Worked example, not a recommendation.
Four bills that between them could ruin four separate fortnights become one number you never think about again until one of them changes.
Where the money sits
In a separate account, and the separation is doing real work. Money for a bill nine months away looks exactly like spendable money if it's sitting in your everyday account, and it will be treated that way.
A second everyday-transaction account is usually enough. What it wants is the direct debits pointed at it, so the bills draw from it directly. What it does not want is to be somewhere you have to think about, or somewhere with a withdrawal delay when a bill lands early.
The two-account setup is covered in more detail in the pillar guide.
The first year is the hard one
Here's the part most explanations skip. Dividing a yearly bill by 26 assumes you've been setting aside for a full year already. If registration is due in three months and you started last fortnight, six set-asides of $34.23 gives you $205, against a bill of $890.
That gap is real and there's no clever way around it. There are two honest options.
Put in more than the smoothed amount until the first instance of each bill is covered, which front-loads the pain but gets you to steady state fast. Or accept that the first occurrence of each big bill is partly funded from somewhere else, and let the method come good from its second cycle onward. Neither is a failure. It's the ramp-up, and every smoothing system has one.
What matters is knowing which of the two you've chosen, rather than discovering in month three that the account is short.
Bills that change
Power and water don't repeat the same figure. Smoothing still works, it just needs a number to start from.
Last year's total is the usual starting point, adjusted if you know something has changed. Then check it once a year rather than every bill. Chasing every variation defeats the purpose, which was to stop thinking about it.
If the account drifts consistently short or consistently long over a few cycles, the input figure was wrong. That's a once-a-year correction, not a monthly worry.
When smoothing is the wrong tool
Three cases, honestly.
A bill you can't predict at all, like a medical cost or a repair, can't be smoothed because there's no yearly figure to divide. What's left over each payday is what absorbs those, and working out that figure is its own exercise. That's what a general buffer is for, and it's a different mechanism.
A bill that's genuinely unaffordable doesn't become affordable by being divided by 26. Spreading it out makes the size visible in per-payday terms, which is useful information, but the total hasn't moved.
And a bill arriving within the next cycle or two doesn't need smoothing, it needs paying. Smoothing is for the ones far enough away that the money has time to accumulate.
Doing it without the admin
The maths is one division. The admin is the part that wears people down: redoing it when a bill changes, tracking which have already come out this cycle, keeping the ramp-up straight in your head.
That's the part I built EachPayday to handle. It converts every bill to your pay cycle, monthly, quarterly or yearly, gives you the payday checklist, and tracks that each debit is covered, with your data staying on your own device. The set-aside method guide covers how it handles the ramp-up and mid-year changes.
Questions people ask
How do I work out a fortnightly amount for a yearly bill?
Divide the yearly cost by 26. A $890 car registration is $34.23 a fortnight. For weekly pay divide by 52, and for monthly pay divide by 12.
Where should the set-aside money be kept?
A separate account from the one you spend from, with the relevant direct debits pointed at it. The separation is what stops money committed to a bill nine months away from looking spendable today.
What do I do about the first year, before the set-asides have built up?
Either contribute more than the smoothed amount until the first instance of each bill is covered, or accept that the first occurrence is partly funded from elsewhere and the method reaches steady state from the second cycle. Both are normal; the ramp-up is inherent to any smoothing system.
How do I smooth a bill that changes every time, like power?
Start from last year's total for that bill, divide by your number of paydays, and review the figure once a year rather than after every bill. If the account runs consistently short or long across several cycles, the starting figure needs adjusting.
Can every bill be smoothed?
No. Smoothing needs a predictable yearly total, so unpredictable costs like repairs or medical bills are handled by a general buffer instead. A bill due within the next cycle or two also needs paying rather than smoothing.
This article is general information, not financial advice, and does not take your circumstances into account. See the disclaimer.