How the monthly figure is worked out, which bills belong on the list, and when each one is worth shopping around for.
Annualiser is a free UK savings calculator for annual and irregular bills. You list the bills you know are coming — car insurance, Christmas, the MOT, the boiler service — and it divides each one by the number of months before it lands, then adds those up into a single amount to put aside each month. When the bill arrives, the money is already there.
Take each bill, divide it by the number of whole months between now and the month it is due, and add the results together. A £900 car insurance renewal five months away is £180 a month. A £1,200 Christmas eleven months away is £109.10 a month. Together that is £289.10 a month. Annualiser does this sum for every bill on your list and keeps it up to date as the months tick down.
No. Annualiser never connects to a bank, reads transactions or categorises spending. You type in the bills you already know about — the amount and roughly when it is due — and it does the arithmetic. There is nothing to authorise and no open banking involved.
Yes. The bills calculator is free and has no limit on how many bills you add. There is a paid tier, Annualiser Plus, which adds a full monthly budget on top; the bills tool itself stays free.
Not really. Amounts are in pounds sterling only and the renewal guidance is built around UK conventions — the MOT, vehicle tax, the TV licence, UK insurance renewal windows. The underlying maths would work anywhere, but the currency and the advice would not.
For each bill, Annualiser counts the months in which a contribution can still arrive before the money is needed, divides the amount by that number, and rounds up to the nearest penny. The day of the month matters: if you are saving on the 12th and a bill goes out on the 1st of December, that December contribution lands eleven days too late, so it is not counted. Each bill is rounded up before they are added together, so the total can never leave you a penny short. Bills more than a year out use the same formula — an £1,800 cost eighteen months away is £100 a month.
Neither one gets spread. There are no months left to spread it over, so putting it in the monthly figure would understate what you actually need. Annualiser pulls both out and reports them together as "needed now" — while still saying which part has already passed and which part is simply imminent — and the monthly saving figure stays clean.
It answers a different question from the monthly figure: not what to add this month, but where the pot should already stand today. Each bill accrues over the months of its own cycle, so a yearly bill due in five months is seven months into its year and should be about seven twelfths funded. Add that up across every bill still to come and you get the pot figure. Tell Annualiser what is actually in your savings pot and it will show you the difference — whether you are ahead of that figure or behind it, and by how much.
Because the two answer different questions. Annual total ÷ 12 is the steady-state cost: what these bills come to per month once your pot is already where it should be. The headline figure is what it takes to be ready for each bill from where your pot stands now — and a bill three months away has to be funded over three months, not twelve. The gap between the two is catch-up, not a new cost, and it shrinks as the pot fills. Annualiser shows both, and explains the difference under the pot.
Yes. Each bill has a cycle — yearly by default, but you can set two years, three, five, six months or three, or mark it a genuine one-off. The cycle sets how the pot accrues and what the bill costs in the steady state, and it is what the date rolls forward by when you mark the bill paid. A phone replaced every two years accrues over twenty-four months rather than twelve.
Yes — put the event date in and set how many days early the money is wanted. A birthday on 4 February with three weeks’ notice needs funding by 14 January, and Annualiser works to that date rather than to the birthday. It is the same arithmetic people already do by hand in a spreadsheet column.
Usually because a bill got closer. The same £900 spread over five months is £180; over four months it is £225. Nothing changed about the bill — there is simply less time left to save for it. This is why the figure is worth checking monthly rather than setting once, and why adding bills early costs you less per month than adding them late.
Anything paid as a lump sum or landing once a year, rather than every month. The common ones are car insurance, home insurance, the MOT and car service, vehicle tax, Christmas and birthdays, holidays and flights, pet insurance and vet bills, the boiler service, the TV licence, and annual software or streaming subscriptions. Anything on a monthly direct debit — gas and electricity, broadband, childcare — is deliberately not here, because it is already spread across the year and there is nothing left to spread. Annualiser ships a catalogue of 59 lump-sum costs so you are not working from memory.
Some costs are not bills at all — they are things that wear out, where the sensible move is saving toward the next one rather than being ambushed by it. A car, a phone, a laptop, a boiler, a mattress, a sofa. You enter the replacement cost and roughly when you expect to need it, and Annualiser spreads it exactly like a bill. There is no renewal to shop around for, so these carry no review date.
Estimate both. A rough figure saved monthly beats an exact figure you find out about three weeks before it is due. Last year’s amount plus a bit is usually close enough, and you can correct it the moment the real renewal letter arrives — the monthly figure recalculates immediately.
Yes, and it is expected. Nothing stops you having "Car insurance" on the list twice. Each bill carries an optional provider and a free-text note, which is what makes the pair readable at a glance, and you can tag them — "Car 1", "Car 2" — to filter the list and see what each vehicle costs you a month on its own.
It varies by bill and the differences are worth real money. Car insurance is cheapest bought about 21 to 26 days before renewal. Home insurance is around 15 to 25 days. Energy is roughly 49 days before a fixed tariff ends. Broadband is about 30 days before the contract ends. Annualiser stores the right lead time for each catalogue item and counts back from the due date, so it tells you when the window opens rather than leaving you to remember.
Insurers price on risk, and someone shopping weeks ahead of renewal looks like a lower risk than someone buying at the last minute. The effect is well established in UK motor and home insurance and the gap between the cheapest day and renewal day can run to a meaningful share of the premium. Buying too early has its own penalty, which is why the sweet spot is a window a few weeks out rather than "as early as possible".
Plus adds a full monthly budget — one income group and thirteen spending categories, with each item entered weekly, monthly or yearly and normalised to a monthly figure. The header shows what is coming in, what is going out and what is left. Every bill’s monthly saving flows into the budget automatically as a line in its matching category, so car insurance lands under motoring and Christmas under big one-offs without you re-entering anything.
No. Bills live in the same place on both plans, so upgrading adds the budget view and changes nothing about the bills you have already entered.
No. It is a calculator and a reminder of when renewal windows open. It does not recommend products, compare quotes, or tell you what to buy, and nothing in it is regulated financial advice.
Add the bills you know are coming and Annualiser does the sum for all of them at once.
Get started — it’s freeNot sure what to add? Work through the checklist of 59 annual bills.