Turning a Goal Into a Monthly Number
"I want to save $20,000" is a wish. "I will move $497 into savings on the first of every month for the next three years" is a plan. The difference is a single number, and that number is what this calculator gives you. It works backwards from your goal: it grows whatever you have already saved, works out the remaining gap, and finds the level monthly deposit that closes it by your deadline — including any interest the account pays along the way.
The formula behind it
r is the monthly interest rate (annual rate ÷ 12) and n is the number of months. When the interest rate is zero the formula simplifies to the gap divided by the number of months.
Worked example: a house deposit
You want $20,000 for a home deposit in three years and already have $2,000 in a savings account paying 4% a year. Your $2,000 grows to about $2,255 on its own, leaving a gap of roughly $17,745. Spread over 36 months with interest, you need to save about $465 per month. Without interest the figure would be $500 — interest saves you roughly $1,250 of your own money.
Common goals and typical time frames
| Goal | Typical horizon | Where people often keep it |
|---|---|---|
| Emergency fund | 6–18 months | High-yield savings account |
| Car purchase | 1–3 years | Savings account or short-term deposit |
| Home deposit | 2–5 years | Savings account, certificates of deposit |
| Wedding or big trip | 1–2 years | Savings account |
| Child's education | 10–18 years | Dedicated education accounts, diversified funds |
A useful rule of thumb: money you need within about five years is usually kept somewhere stable rather than in the stock market, because a market downturn just before your deadline could leave you short. For longer horizons, see the compound interest calculator to explore higher-growth scenarios.
Tips for actually hitting your goal
- Pay yourself first. Schedule the transfer for the day after payday, before you have a chance to spend the money.
- Use a separate account. Money that is out of sight in a named account ("House 2029") is far less likely to be spent.
- Break it down. The per-day figure is often surprisingly small — comparing it to a daily coffee or lunch makes trade-offs concrete.
- Direct windfalls to the goal. Tax refunds, bonuses and gifts can shorten your timeline by months.
- Review every quarter. If you fall behind, recalculate with the new numbers rather than giving up.
Frequently Asked Questions
What if my current savings already cover the goal?
If your existing savings will grow to the goal by the deadline at the interest rate you entered, the calculator shows $0 per month — you only need to leave the money where it is.
Should I include interest in my plan?
If the money sits in an interest-bearing account, yes — it lowers the amount you need to deposit. If you are unsure, enter 0% to get a conservative figure; any interest you do earn will then put you ahead of schedule.
How do I save for several goals at once?
Run the calculator once per goal and add up the monthly amounts. If the total is more than you can afford, extend the deadline of the least urgent goal or prioritise your emergency fund first.
Does it matter which day of the month I save?
Only slightly. The calculator assumes deposits at the end of each month. Saving at the start of the month earns a little more interest.
Disclaimer: This calculator is for educational purposes only and does not constitute financial, tax or investment advice. Results are estimates based on the assumptions you enter; real returns, rates, fees and taxes vary. Consider speaking with a licensed financial professional before making decisions.
Related tools