Savings Calculator

How to use this calculator

1. Enter or choose initial deposit.
2. Enter or choose monthly deposit.
3. Enter or choose increase deposits each year by.
4. Enter or choose interest rate (per year).
5. Enter or choose compounding.
6. The balance at the end updates as you type. Use Copy result or Share to keep it.

Method

Each month: Balance = Balance × (1 + i) + Deposit, where i = (1 + r ÷ k)^(k ÷ 12) − 1, less tax × interest. Without tax or rising deposits: FV = P(1 + i)^n + D × ((1 + i)^n − 1) ÷ i

P

initial deposit

D

monthly deposit

r

annual interest rate

k

compounding periods per year

i

equivalent monthly rate

n

number of months

Worked example

1. Monthly rate i = 6% ÷ 12 = 0.5%; n = 120 months.
2. Initial deposit: 1,000 × 1.005^120 = 1,819.40.
3. Monthly deposits: 100 × (1.005^120 − 1) ÷ 0.005 = 16,387.93.
4. Balance = 1,819.40 + 16,387.93 = 18,207.33, of which 13,000 was deposited.

Saving $100 a month on top of $1,000 at 6% compounded monthly gives $18,207.33 after 10 years, including $5,207.33 of interest.

What the result means

The gap between the two lines in the chart is interest. It is small at first and widens every year, so starting earlier matters more than the exact rate. Compare the balance with the Inflation Calculator to see what it will buy.

Assumptions and limits

• The interest rate stays the same for the whole period.
• Deposits are made at the end of each month; a yearly increase applies from the start of each new year.
• Tax, if entered, is taken from the interest as it is earned.
• For yearly, quarterly or daily compounding the rate is converted to the equivalent monthly rate.
• Savings rates change; most accounts are variable.
• Inflation and account fees are not deducted.