Four decisions to make before calculating
- The target, in money of the target date. The calculator treats the target as a future amount. If you priced the goal in today's money, adjust it first, as shown in the inflation section below.
- What is already saved toward this goal. It is grown at the same assumed rate and credited before any new deposit is calculated.
- The rate assumption. Run 0% first. That shows the pure saving burden with no help from returns. Then try a rate you could realistically earn after fees.
- The horizon in whole years. The tool counts 12 month-end deposits per year.
i is the annual rate ÷ 12 as a decimal, N the number of monthly deposits, G the gap left after existing savings have grown, and C the equal deposit at each month-end. At 0%, C = G ÷ N.
One goal at three rates and five horizons
Here is the monthly deposit needed to reach 1,000,000 currency units starting from nothing.
| Years | At 0% | At 6% | At 10% |
|---|---|---|---|
| 5 | 16,666.67 | 14,332.80 | 12,913.71 |
| 10 | 8,333.33 | 6,102.05 | 4,881.74 |
| 15 | 5,555.56 | 3,438.57 | 2,412.72 |
| 20 | 4,166.67 | 2,164.31 | 1,316.88 |
| 25 | 3,333.33 | 1,443.01 | 753.67 |
Check the 10-year, 6% cell by hand: i = 0.06 ÷ 12 = 0.005 and N = 120. (1.005)^120 = 1.819397, so the future value of one unit a month is 0.819397 ÷ 0.005 = 163.879. Then 1,000,000 ÷ 163.879 = 6,102.05.
The rate matters little over five years: 10% instead of 0% cuts the deposit by about 23%. Over 25 years the same change cuts it by 77%, from 3,333.33 to 753.67. Returns need time to do their share of the work.
Savings Goal CalculatorEnter your own target, savings so far, assumed rate and years to get the monthly amount.Why starting earlier matters more than it looks
Compare two savers with the same 1,000,000 goal at 6%. One starts 20 years before the target date and deposits 2,164.31 a month, putting in 519,434.54 of their own money. The other waits ten years and needs 6,102.05 a month, putting in 732,246.02. Waiting a decade makes the monthly amount 2.82 times larger and costs 212,811.48 more of the saver's own money.
At 0% the bars would all equal 1,000,000. Without a positive return, time only spreads the same burden across more months; with one, time reduces the burden itself. The same compounding effect is shown for a single lump sum in compound versus simple interest.
Counting money you already have
Suppose 200,000 is already saved for the same 10-year, 6% goal. At 6% it grows to 363,879.35 by the target date, leaving a gap of 636,120.65. The monthly deposit falls from 6,102.05 to 3,881.64. If the existing balance alone grows past the target, the calculator reports zero; 200,000 already covers a 300,000 goal in that case.
The same arithmetic tells you what lump sum would cover the goal with no monthly saving at all: 1,000,000 ÷ 1.005^120 = 549,632.73 today, at the assumed 6% for 10 years. If you expect a bonus or an asset sale, entering it as savings already held shows how much of the monthly burden it removes.
Adjusting the target for inflation yourself
The calculator does not model inflation. Its target is a nominal amount on the target date. If your goal is priced in today's money, such as a car or tuition fee quoted now, grow the price first and enter the result as the target.
π is your assumed yearly inflation rate as a decimal. Base it on the official consumer price series for your country and revisit it each year rather than picking a convenient number.
| Assumed inflation | Target to enter | Monthly deposit | Change from ignoring inflation |
|---|---|---|---|
| None | 1,000,000 | 6,102.05 | — |
| 7% a year | 1,967,151 | 12,003.65 | +5,901.60 a month |
The 7% figure is an illustration, not a forecast. The lesson is the size of the effect: at an inflation rate above your return, the deposit roughly doubles over ten years. Another common method uses a real rate, (1 + return) ÷ (1 + inflation) − 1, with a target in today's money. Here that rate is −0.93%, and the calculator accepts only rates of 0% or more, so growing the target is the method that works with this tool.
Where the monthly figure can mislead
- Deposits are assumed at each month-end. Saving at the start of each month earns one extra month of growth per deposit; the investment calculator has a start-of-month option to test that.
- The rate is fixed. Market returns vary, and a fall shortly before the target date hurts more than one early on, because more money is exposed.
- Tax on profit or interest and account fees reduce the effective rate. Enter a rate net of both.
- Equal deposits are assumed. If you plan to raise the deposit as income rises, the tool's figure is a conservative starting level, not your schedule.
If the goal is a home deposit, the related questions of borrowing are covered in how much loan you can afford.