How the calculation works
Each month, the balance earns a twelfth of the yearly interest rate, then your deposit is added. To find the monthly amount needed, the calculator works out how much your current savings will grow to by the goal date, and spreads the gap over the months, allowing for the interest each deposit earns on the way:
Monthly saving = (goal − savings × (1 + i)n) × i ÷ ((1 + i)n − 1)
where i is the monthly interest rate and n the number of months. For short goals the interest makes only a small difference. Over many years it can do a large share of the work.
Tips for hitting a savings goal
- Automate it. Set up a standing order or automatic transfer for payday, so the money moves before you can spend it.
- Use a separate account for each big goal, so you can see progress and aren't tempted to dip in.
- Check the rate you're actually getting. Many easy-access accounts pay far less than the best rates on offer, and switching takes minutes.
- Use tax-free accounts where you can, such as an ISA in the UK or a high-yield account inside a tax-advantaged plan in the US, depending on the goal.
- Build an emergency fund first. Three to six months of essential costs stops one surprise bill turning into debt.
FAQ
Should I include investment growth?
For goals under about five years, use a savings rate and don't count on investment returns, because markets can fall just when you need the money. For longer goals, a cautious expected return can be reasonable.
What about inflation?
Prices rise over time, so a goal several years away may cost more than today. A simple fix is to raise the goal by a few percent for each year until you need it.