Savings goal calculator: how much to save each month

This calculator tells you the fixed amount to save each month to reach a savings target by a chosen date. You enter where you want to end up, what you already have, the interest rate you expect, and how many years you have. It returns the monthly deposit that gets you there, with compound interest doing part of the work so you pay in less than the target itself.

How to use it

Fill in four fields:

• Target amount — the sum you want to have at the end.
• Starting amount — what you already have set aside for this goal, or zero if you are starting fresh.
• Interest rate — the annual rate you expect your savings to earn.
• Years — how long until you need the money.

The result is the monthly saving required. Change any field and the answer updates, so you can test what happens if you stretch the deadline, raise the rate, or start with a lump sum already in place.

How the answer is worked out

Most savings maths runs forwards: you know what you pay in each month, and you work out what it grows to. This calculator runs that same maths backwards. You already know the end figure, so it solves for the one unknown — the monthly deposit.

The link between the two is compound interest. Money you save early earns interest, and that interest then earns interest of its own, so each deposit is worth more than its face value by the time you reach your goal. This is the future value of a stream of regular payments, and it grows faster than the deposits alone would suggest.

Because interest contributes, the total you pay in is smaller than the target. The calculator accounts for that. It works out how much your starting amount alone will grow to, subtracts that from your target, and then finds the monthly deposit whose compounded future value covers the gap that remains.

A worked example

Say you want €20,000 in five years, you are starting from zero, and you expect a 3% annual rate with interest added monthly.

The calculator returns €309.37 a month. Over five years, that adds up to €18,562 paid in from your own pocket. The remaining €1,438 comes from interest. So while the goal is €20,000, you only ever hand over €18,562 — compounding supplies the rest.

Raise the rate and interest carries more of the load, dropping the monthly figure. Shorten the timeline and you lose compounding time, so the monthly figure climbs.

Assumptions

The calculator keeps the model simple so the mechanics stay clear:

• Deposits are made at the end of each month.
• Interest compounds monthly.
• The rate stays constant for the whole period.
• No fees, tax, or inflation are applied, so the result is in today’s euro before any deductions.

This is an educational tool, not financial advice. Real savings accounts vary in how and when interest is paid, and a personal savings plan is best confirmed with a qualified adviser. The calculation runs entirely in your browser — nothing you type is sent anywhere.