For UK couples, families and housemates
Know where your pay goes.
Share the household’s totals, and keep private any account you choose.
Free at the moment. No bank logins or card details.
Example figures. Alex gets paid £2,840.00. Where should it all go? MMJJS shares it out by Alex’s rules: rent, bills and minimum payments, £1,418.60; towards Sam’s car loan, £150.00; Cash ISA and holiday fund, £750.00; extra off the credit card, £321.40; kept for spending, £200.00. Alex moves the money in their banking app and ticks off each transfer. Sam sees what Alex shares. Alex marks the Cash ISA private: it is hidden from Sam, but still in the total, and the combined net worth stays at £18,710.00. Then Alex closes the month, and sees their net worth month by month: £11,120.00 for October, £480.00 more than September.
Private items
Private, but still counted
Mark an account private. It counts in the totals, but no one else sees it.
Alex’s records
| Item | Type | Balance |
|---|---|---|
| Everyday account | Cash | £1,240.00 |
| Holiday fund | Cash | £1,200.00 |
| Cash ISA Private | Cash | £9,500.00 |
| Credit card | Debt | −£820.00 |
| Alex’s net worth | £11,120.00 | |
The household page, as Sam sees it
| Cash | £14,090.00 | |
|---|---|---|
| + | Investments | £8,200.00 |
| + | Household potsBalances of pots that are open | £640.00 |
| − | Debts | £4,220.00 |
| = | Combined net worth | £18,710.00 |
| Item | Type | Balance |
|---|---|---|
| Sam (you) | ||
| Current account | Cash | £2,150.00 |
| Workplace pension | Investment | £8,200.00 |
| Car loan | Debt | −£3,400.00 |
| Alex1 private item not listed | ||
| Everyday account | Cash | £1,240.00 |
| Holiday fund | Cash | £1,200.00 |
| Credit card | Debt | −£820.00 |
Try it
Sam sees the household totals, but not the Cash ISA.
Create an account to try it with your own figures.
Month end
Your pay, planned in five steps
Nothing changes your records until you close the month.
Balances
Enter today’s balances
Pay
Add the pay that arrived
Plan
Share it out by your rules
Transfers
Make them in your banking app
Close
Your records update
Where this pay goes
| Bills and payments firstThis pay’s share of rent, utilities and minimum debt payments | £1,418.60 | |
|---|---|---|
| + | Set aside for pledgesYour monthly pledge towards Sam’s car loan | £150.00 |
| + | Your rulesCash ISA £600.00, Holiday fund £150.00 | £750.00 |
| + | Sent on from the left overTo your credit card, the debt with the highest APR | £321.40 |
| + | Kept in Everyday accountYou chose to keep this for spending | £200.00 |
| = | This pay | £2,840.00 |
Requests
Help each other
Ask for help with a debt, a goal or a cost. Each payment is recorded on both sides.
Open requests, as Alex sees them
| Request | Received and pledged |
|---|---|
| Car loanSam · debt at 7.9% APRYou’ve pledged £1,200.00 | £1,200.00£450.00 received, of £1,800.00 |
Also included · example figures
The rest of your money, in one place
Debt-free date
Debt-free by February 2027
If you keep to this plan: £346.40 a month to debts, highest APR first. About £30.40 of interest on the way.
Goals with a date
Holiday fund · 40% of £3,000
£150.00 a month to reach it by Oct 2027
ISA allowance
£3,600 paid in of £20,000
2026/27 · 151 days to 5 April
Reminders
- A payment on your pledge to “Car loan” is due
- Your month end from 28 Oct is still open
- Payday (Salary): start month end once it’s in
Household activity
- Sam asked for help with “Car loan”, £1,800.00
- The pot “Boiler fund” opened
- You joined the household
Made for UK money
- Cash ISAs, Lifetime ISAs, Premium Bonds
- Stocks & Shares ISAs, SIPPs
- The tax year from 6 April
MMJJS for Windows
On your PC, in its own window
The same records, as a Windows app. Windows tells you when someone pledges, a pot opens or it’s payday, and the taskbar icon shows how many are new.
- Opens with Windows if you like, and waits in the tray
- Ctrl+1 to Ctrl+5 for each section, and Ctrl+comma for your account
- Log in as you do here, with a passkey or your password
Free. For 64-bit Windows 10 and 11, and installs just for you, without an administrator.
If Windows says it doesn’t recognise the app, choose More info, then Run anyway.
Questions
Does it connect to my bank?
No. You type in each balance from your banking app or statement.
Does it move money?
No. You make every transfer yourself, in your banking app. When another member pays towards your request, or a pot pays out to you, their record of it updates yours.
Who can see my records?
Only you, until you join a household. Then members see the names and balances of your accounts, investments and debts that aren’t private, and combined household figures. People you deal with also see the requests you show them, the pledges between you, and your votes and payments in a pot you share. No one sees your pay, bills or rules. The household recap does show the combined monthly surplus, so in a household of two, the other member could work out yours.
What does a private item hide?
Its name and amount, from everyone else, including whoever set the household up. It still counts in the household’s totals, so in a small household its size can sometimes be worked out. You can’t ask for help with a private item, because a request would show it.
What are requests, pledges and pots?
A request asks for help with one of your debts, a savings goal or a particular cost, and you choose who sees it. A pledge is an offer towards a request, as one payment or monthly, up to your monthly surplus; whoever pays records each payment, and both records update. A pot is money the household saves for something shared: members vote to open it, and a treasurer pays out, noting what each payout is for.
What does it cost?
Nothing at the moment, and it doesn’t ask for card details. The terms say how any future change to that would be handled.
Is it financial advice?
No. It adds up what you record, shares out each pay by your rules, then sends what’s left to your highest-APR debt, then your primary investment, unless you keep it. It doesn’t recommend products.
Can I take my records with me?
Yes. Download your records as a JSON file from Account, at any time. You can delete your account there too.
Do I need a household?
No. MMJJS works on your own. You can start a household, or accept an invitation to one, whenever you’re ready.
How do I log in?
With a passkey saved on your device, or with your email address and a password. You choose when you create your account.
Start with this month
You’ll need your balances, your pay and your regular bills.