Savings Goal Calculator
Name the number and the date — get the monthly deposit that hits it, with interest doing part of the work.
The formula behind it
The calculator finds the payment whose future value, plus the growth of what you've already saved, equals the goal:
where r is the monthly rate and n the number of months.
Goal $20,000 in 3 years, starting from $2,000 at 4.5% APY:
Required deposit ≈ $464/mo. You'll deposit about $16,700; growth on your head start and deposits covers the remaining ≈ $1,300.
Same $20,000 goal, same $2,000 start, same 4.5% APY — but this time the deposit is fixed at $300/month. How long does it take?
Rearranging the future-value formula for the number of periods gives about 53 months — roughly 4 years and 5 months — noticeably longer than the 3-year plan above, since $300/month is well under the $464 that plan required.
What extending the deadline buys you
| Years to goal | Required monthly deposit |
|---|---|
| 3 | $464 |
| 4 | $339 |
| 5 | $261 |
| 6 | $211 |
(Same $20,000 goal, $2,000 head start, 4.5% APY throughout.) The drop from 3 to 4 years saves $125/month, but 5 to 6 years only saves $50/month — each additional year of patience buys a shrinking amount of relief, because a longer runway means interest is doing proportionally more of the work.
Common savings-goal mistakes
- Fixing the deposit amount without checking whether it actually reaches the goal in time. As the second worked example shows, a comfortable-sounding number like $300/month can take over a year longer than a tighter deadline assumed.
- Ignoring the effect of extending the deadline. The table above shows diminishing but still meaningful returns from pushing the date back — worth checking before assuming a goal is unaffordable.
- Forgetting that "already saved" money keeps growing too. The formula grows your existing balance at the same rate, so a head start that seems small today (like $2,000) does real work by the deadline.
Hitting goals you actually keep
Savings goals fail on friction, not math. Set up an automatic transfer for the exact amount on payday; break the number down (the daily equivalent above makes a big goal feel survivable); and park the money where the timeline dictates — a high-yield account for short goals, a CD when the date is fixed, investments only for 5+ year horizons. If the required amount is more than you can swing, extend the date rather than abandoning the goal: on the example above, stretching 3 years to 4 drops the deposit from $464 to about $339.
Frequently asked questions
How much do I need to save per month?
$20,000 in 3 years from a $2,000 start at 4.5% APY needs about $464/mo — interest covers ~$1,300.
Should savings goals account for inflation?
For multi-year goals, yes — inflate the target (try the inflation calculator) or use a real rate.
What's the best account for a savings goal?
Under 3 years: high-yield savings. Fixed date: CD. 5+ years: investments you can leave alone.
How long will it take at a fixed monthly amount?
$300/month toward $20,000 from a $2,000 start at 4.5% APY takes about 53 months — roughly 4 years 5 months.
How much does stretching the timeline reduce the deposit?
A lot at first: $464/mo at 3 years, $339 at 4, $261 at 5, $211 at 6 — with diminishing savings each extra year.
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Note: Assumes constant APY and end-of-month deposits. Not financial advice. Last reviewed: September 2026.