Savings Calculator
Plan your savings in three ways: see how much you will have after a time with regular monthly deposits, find the monthly deposit needed to reach a goal by a date, or find how long it takes to reach a goal with a deposit you can afford.
Paid monthly, at one twelfth of the yearly rate.
Result
Enter the time and the rate.
The calculation runs in this browser tab. Nothing you enter is uploaded, saved or logged.
How do regular savings grow?
Money you save every month earns interest, and so does the interest it has already earned. The balance after n months is the starting balance grown by n months of interest, plus each deposit grown for the months it has been in the account. With a monthly rate of one twelfth of the yearly rate, 250 saved every month for 5 years at 3.5%, starting from 1,000, reaches about 17,557, of which 16,000 was deposited and 1,557 is interest.
Three levers move the result: how much you save, how long you save for, and the rate. Time has a large effect: the interest earned grows faster in the later years, because there is more money to earn interest on. The goal modes turn the question around: to reach 20,000 in 5 years from 1,000 you would need to deposit about 287.31 a month.
How to use the Savings Calculator
- Choose what you want to find: the balance, the monthly deposit for a goal, or the time to reach a goal.
- Enter the starting balance (optional), the yearly interest rate, and either the monthly deposit or the goal, as asked.
- Enter the time in years and months, when it is needed, and whether deposits are made at the start or the end of the month.
- Read the result, the amount put in and the interest earned, and look at the year-by-year table.
Formula
- Monthly rate
- i = annual rate ÷ 12
- Balance, deposits at the end of each month
- B = P × (1 + i)^n + D × ((1 + i)^n − 1) ÷ i
- Deposits at the start of each month
- multiply the deposit part by (1 + i)
- Deposit needed for a goal G
- D = (G − P × (1 + i)^n) ÷ (((1 + i)^n − 1) ÷ i)
The calculator simulates month by month with exact arithmetic instead of using the closed formulas, and gets the same figures. The time to a goal is the first month in which the balance reaches it.
The monthly deposit for a goal is rounded up to the next cent so that the goal is reached, so the final balance can be a cent above the goal.
Worked example
Starting with 1,000 and saving 250 a month for 5 years at 3.5% a year. These are the results the calculator gives:
| Question | Result |
|---|---|
| Input: What do you want to find? | How much I will have |
| Input: Starting balance (optional) | 1000 |
| Input: Monthly deposit | 250 |
| Input: Annual interest rate | 3.5 % |
| Input: Years | 5 |
| Input: Deposits are made | At the end of each period |
| Balance after 5 years | 17,557.47 |
| Total put in | 16,000.00 |
| Interest earned | 1,557.47 |
Assumptions and limits
- The rate is assumed to be constant and the interest is added monthly at one twelfth of the yearly rate. Real savings accounts change their rates and may credit interest differently.
- Taxes, fees and inflation are not included. Inflation reduces what a given amount buys in the future.
- Terms are limited to 100 years (1,200 months). If a goal cannot be reached in that time with the amounts you enter, the calculator says so.
- Investments that can lose value do not behave like a savings account with a fixed rate. These results are a calculation from the numbers you enter, not financial advice.
Frequently asked questions
How much will I have if I save a fixed amount every month?
It depends on the amount, the time and the interest rate. Saving 250 a month for 5 years at 3.5% from a starting balance of 1,000 gives about 17,557. At 0% it would be exactly 16,000.
How much should I save each month to reach a goal?
Choose “The monthly deposit needed to reach a goal”, and enter the goal, the rate and the time. To reach 20,000 in 5 years at 3.5% from 1,000, you need 287.31 a month.
How long will it take to reach my savings goal?
Choose “How long it takes to reach a goal” and enter your monthly deposit. 250 a month from 1,000 at 3.5% takes 5 years and 9 months to reach 20,000.
Should I deposit at the start or the end of the month?
The start-of-month option assumes each deposit earns interest for the whole month, so the result is slightly higher. It matters most with high rates and long terms. Choose the one that matches when your deposit really reaches the account.
How much of my balance is interest?
The page splits the final balance into what you put in and the interest earned. Interest is a small share at first and a growing one over time.
Does inflation matter for savings?
Yes. If prices rise faster than your interest rate, your savings buy less each year even though the balance grows. The calculator does not adjust for inflation, so compare the rate you enter with the expected rate of inflation.