Savings Calculator
$
$
7.00%
20 yrs
Future Value$300,850.72
Total Contributions$130,000.00
Total Interest$170,850.72
- Total Balance
- Contributions
Regular saving combined with compound interest can grow a modest balance into a substantial fund over time. This savings calculator starts with an initial deposit, adds a fixed monthly contribution, and compounds the whole balance monthly at your chosen annual rate. It reports the future value, the total you actually deposited, and the interest the compounding earned on top.
Formula
FV = P(1 + i)^n + PMT · ((1 + i)^n − 1) / i
- P
- Initial deposit
- PMT
- Monthly contribution, added at the end of each month
- i
- Monthly rate = annual rate ÷ 12 ÷ 100
- n
- Total months = years × 12
How it works
- Enter your initial deposit, the amount you will add every month, the annual interest rate, and the number of years you plan to save.
- The calculator compounds monthly: the initial deposit grows as a lump sum while each monthly contribution is added at the end of its period and earns interest from then on.
- It shows the projected future value, your total contributions (initial deposit plus all monthly deposits), and the total interest, which is the future value minus those contributions.
Worked example
Starting with $1,000, adding $200 a month for 10 years at a 5% annual rate compounded monthly.
- Monthly rate i = 5 ÷ 12 ÷ 100 = 0.0041667; months n = 10 × 12 = 120.
- Future value of the lump sum plus the 120 monthly deposits works out to $32,703.47.
- Total contributions: 1,000 + 200 × 120 = $25,000; interest: 32,703.47 − 25,000 = $7,703.47.
Future value about $32,703.47, total contributions $25,000, and interest earned about $7,703.47.
Frequently asked questions
- How often does this calculator compound interest?
- It compounds monthly, which matches how many high-yield savings accounts and money market accounts credit interest. Each monthly contribution starts earning interest from the end of the month it is deposited.
- Does it account for inflation or taxes on interest?
- No. The future value is in nominal dollars and assumes a steady rate. Inflation reduces real buying power over time, and interest earned in a taxable account may be taxed, so treat the result as a gross projection.
- What is the difference between contributions and interest in the result?
- Contributions are the money you put in yourself, namely the initial deposit plus every monthly deposit. Interest is everything the account earned beyond that, which is the projected balance minus your total contributions.