Home / Financial / Savings Calculator
Savings Calculator: Reach Your Savings Goal
Set a target amount and either a deadline or a monthly deposit. The calculator solves for the missing piece, using monthly interest, and shows how the balance builds year by year.
The maths of a savings goal
A savings plan combines two growing pieces: the money already saved, which compounds on its own, and a stream of equal deposits. With monthly rate i (annual rate ÷ 12), n months, starting balance S and deposit d:
Balance = S × (1 + i)n + d × ((1 + i)n − 1) ÷ i
To find the deposit for a goal G, rearrange: d = (G − S × (1 + i)n) × i ÷ ((1 + i)n − 1). To find the time instead, solve for n using logarithms: n = ln((G + d ÷ i) ÷ (S + d ÷ i)) ÷ ln(1 + i), then round up to the next whole month. With a rate of zero the formulas collapse to d = (G − S) ÷ n and n = (G − S) ÷ d.
Reading the results
The deposit mode answers: how much must I put aside each month to be there on time? The time mode answers: given what I can afford, when will I get there? Compare both to your budget. If the required deposit is more than you can manage, extend the deadline, lower the goal or look for a better rate. The table shows how much you deposited each year and the balance at each year end.
Notice how interest contributes more as the balance grows. Over a short horizon of a year or two, nearly all of the goal comes from your own deposits, so the rate matters little. Over a decade it matters much more.
Practical points for savers
- Match the account to the timeline. Money needed within a few years usually sits in low-risk accounts, which means modest returns. Use the lower rate you would realistically receive.
- Allow for inflation. If the goal is a future price, such as a car or tuition, it may rise before you buy. The inflation calculator can estimate the larger target.
- Automate deposits. A transfer on payday is easier to keep up than a manual one.
- Keep an emergency buffer. A separate fund prevents you raiding this goal.
Assumptions and limits
The calculator assumes a fixed rate compounded monthly, level deposits at month end and no withdrawals. Real accounts may pay variable rates, credit interest daily, impose minimum balances or tax the interest. If the account pays interest on a different schedule, the result will differ slightly. Treat the output as a planning estimate and confirm the terms of the account you use. For a longer-term growth model with contributions see the compound interest calculator.
Worked example
A family wants 15,000 for a home deposit in three years. They already hold 1,500 in an account paying 3.5% a year.
Inputs
| What do you want to find? | Monthly deposit needed by a deadline |
|---|---|
| Savings goal | 15000 |
| Already saved | 1500 |
| Annual interest rate | 3.5 % |
| Years until you need the money | 3 |
Result
To reach 15,000.00 in 36 months at 3.5% a year.
| Balance at the end | 15,000.00 |
|---|---|
| Starting balance | 1,500.00 |
| Deposits you make | 12,665.81 |
| Interest earned | 834.19 |
Yearly balance
| Year | Deposited | Balance at the end |
|---|---|---|
| Year 1 | 4,221.94 | 5,843.68 |
| Year 2 | 4,221.94 | 10,341.85 |
| Year 3 | 4,221.94 | 15,000.00 |
- Interest is added every month and deposits are made at the end of each month. In the time mode the last deposit may overshoot the goal slightly.
Financial disclaimer: Results are estimates for planning and education. They are not financial, tax or legal advice. Fees, taxes, rates and rules vary by lender, product and country, so confirm figures with your provider or a qualified adviser before making decisions.
Frequently asked questions
How much should I save each month to reach a goal?
Subtract the growth on what you already hold from the goal, then divide by the future value factor for the number of months. The calculator does this and shows the monthly deposit.
Why is the time shown in whole months?
Deposits are made monthly, so the goal is reached on the first month end when the balance is at or above it. The answer is rounded up to a full month.
What if I do not earn any interest?
Enter a rate of zero. The deposit is then just the remaining amount divided by the number of months.
Should I include money I already have?
Yes, enter it as already saved. It grows with interest while you add deposits, and it reduces the monthly amount needed.
Does this account for tax on interest?
No. If interest is taxed where you live, enter a rate reduced for the tax to get a closer estimate.
Related calculators
References and sources
- Standard time-value-of-money texts: future value of an ordinary annuity and the sinking-fund payment.
- Consumer Financial Protection Bureau: educational guides on saving and building emergency funds. Link