How this is calculated
monthly = (goal − already_saved × (1+r)^n) × r ÷ ((1+r)^n − 1), where r = annual rate ÷ 12 and n = months
This calculator works backwards from the goal. Most savings tools ask what you can afford and tell you where you'll end up; this one asks where you want to end up and tells you the monthly deposit that gets you there — usually the more useful direction.
The math accounts for two helpers: the money you've already saved keeps compounding on its own, and every new deposit earns interest from the month it lands. That's why the required monthly amount is always lower than simply dividing the remaining gap by the number of months — sometimes dramatically lower over long timelines.
A practical note: the biggest lever is rarely the interest rate. Doubling your timeline roughly halves the monthly requirement, while moving from a 2% to a 4% account changes it far less on short horizons. Pick the timeline first, then shop for the rate.
Frequently asked questions
What rate should I use?
For short-term goals (under ~5 years), use your actual savings account rate — typically 3-5% for high-yield accounts. Stock-market rates aren't appropriate for short-term goals, because a bad year can arrive exactly when you need the money.
Should the money sit in savings or investments?
The common rule of thumb: money needed within 3-5 years belongs in savings or similar low-risk accounts; longer-horizon money can consider investments. This tool works for either — just change the rate.
What if I can't afford the monthly amount?
Stretch the timeline or trim the goal — the math updates instantly. A goal you fund at half the pace still arrives; a goal you abandon doesn't.
Is interest taxed?
In most countries, savings interest is taxable income. The tool shows pre-tax growth; your actual net result will be slightly lower depending on your tax rate.