Your monthly saving figure comes from two sums meeting: your real capacity —the average of net income minus total spending over two or three months, with annual costs spread across the year— and what each goal demands, which becomes a monthly amount by dividing it by the months remaining. The usual order is minimum cushion, expensive debt, near-dated goals and then the long term. A percentage is a diagnosis, not a plan: a small figure sustained beats an ambitious one abandoned.
"Save 20 % of what you earn" is at once the most repeated and the least actionable piece of money advice there is: it gives you a percentage when what you need is a transfer with a specific amount on the day you get paid. And the jump from percentage to number is not a simple multiplication, because 20 % of your pay almost never matches what genuinely remains at the end of the month.
How much should I save each month?
There is no universal figure, and the percentage everyone quotes is a diagnosis, not a plan. Your number comes from two directions at once: from above, what genuinely remains at the end of the month; from below, what the goals you already have with a date attached demand. When the two sums meet, you have your number.
If you only look at the percentage, you get a figure that sounds good in January and gets abandoned in March. If you only look at the goals, you get an amount that does not fit in your account. The exercise is making the two meet.
Start from your real capacity, not the ideal
Your saving capacity is the average of net income minus total spending over the last two or three months. Two details change the result a lot:
- Spread annual costs across the year. Insurance, property tax, the car service, tuition: if you do not divide them by twelve, your capacity will look bigger than it is and the plan will break the month one of them lands.
- Do not calculate from a good month. A month with no surprises is not your average month; it is your best month.
- With irregular income, widen the window. If you invoice by project, an average of six to twelve months is far more honest than three. And if you are self-employed, strip out what is not yours first: the VAT you collect and the withholdings on your invoices are not income, they are money in transit that you will have to settle in form 303.
If you have never measured your actual percentages, the 50/30/20 rule is a good frame for that first diagnosis before fixing any figure.
From the goal to the monthly amount
The other half of the calculation runs the other way: instead of asking how much you can, you ask how much the things you have already decided to do require. The arithmetic fits on one line: amount ÷ months remaining = what you have to set aside.
| Goal | Amount | Timeframe | Per month |
|---|---|---|---|
| One month of expenses as a cushion | €1,400 | 7 months | €200 |
| Replacing the car | €6,000 | 24 months | €250 |
| Full emergency fund | €8,400 | 42 months | €200 |
This is where the rule that organises everything shows up: a goal without a date is not a goal, it is a wish, and a wish does not produce a monthly amount. Adding the date is what turns "I want to save for a car" into "€250 on the 1st".
Once you have an amount and a timeframe, it pays to see the number rather than imagine it: in the savings simulator you can try combinations of contribution and months and see how much adding €50 pulls the goal forward. The simulator accepts an annual return, but treat it as what it is: an assumption you type in, not a forecast.
What order the goals go in
When your capacity does not cover everything at once —the normal case— you need an order. The one most commonly used is nobody's recommendation, it is plain arithmetic of risk and cost:
- A minimum cushion first, even if it is only one month of expenses: without it, any surprise gets paid with debt and undoes the rest of the plan.
- Then expensive debt. Reducing a balance that costs you a high rate has an effect known in advance; nothing else on this list does.
- Next, goals with a near date, which are the ones that genuinely need the money available within a set period.
- And last, the long term, which has the most time to recover from a bad year.
This guide deliberately stops here: it explains the order and why it is usually framed that way, but it does not get into which product to open, where to put each block or what return to expect. That depends on your situation and no one should decide it for you in the abstract. For the first step, the full mechanics are in the emergency fund guide.
What if I cannot reach 20 %?
Then your figure is whatever comes out, and it still counts. The percentage is there to compare you with yourself over time, not with someone else’s average. Setting aside 6 % every month for two years ends up weighing more than aiming for 20 %, missing in month three and giving up.
What does move the figure over time is mechanical, not motivational: automate the transfer for the day you get paid (whatever is left at the end of the month does not get saved, it gets spent), raise the contribution when your income rises instead of absorbing it into spending, and revisit the number every time a large fixed cost changes. Before taking a new one on —a pricier rent, a monthly payment— you can see what it does to your margin in can I afford it?.
Common mistakes
- Setting the figure on gross salary instead of what actually lands in the account.
- Calculating capacity from a month with no surprises and treating it as typical.
- Forgetting annual costs: the plan survives eleven months and breaks in the twelfth.
- Saving "whatever is left" at the end of the month, which is statistically zero.
- Goals with no date: no timeframe means no monthly amount, and no amount means no habit.
- Aiming at an ambitious percentage, missing in month three and dropping the whole system.
- Never revisiting the figure when income or fixed costs change.
