Savings Calculator
Project how your savings account balance grows over time, combining a starting amount with regular monthly deposits at your bank's APY. This assumes an FDIC-insured deposit account, not a market investment.
Your projected savings balance will appear here
Enter your starting amount, deposit, and APY, then click calculate.
Quick Answer
FV = PV(1 + i)^N + PMT x [((1 + i)^N - 1) / i], where i is the monthly rate that matches your APY and N is the number of months. On $1,000 to start, $200 a month, 4.5% APY, and 5 years, that ends up around $14,644.53, with about $1,644.53 of that from interest.
How It Works: Formula & Variables
FV = PV(1 + i)^N + PMT × [((1 + i)^N − 1) / i] | i = (1 + APY)^(1/12) − 1
- PV
- Your starting balance in the account.
- PMT
- Your monthly deposit.
- APY
- Your bank's advertised annual percentage yield, entered as a percentage.
- i (Monthly)
- The monthly rate that compounds to exactly your APY over a year. Dividing the APY by 12 instead would compound it twice and overstate the balance.
- N (Periods)
- The number of monthly deposits, or 12 times the number of years.
Under the federal Truth in Savings Act (Regulation DD, Appendix A), APY measures total interest paid based on the rate and compounding frequency, using a 365-day year, so U.S. banks all disclose it the same way.
Source: CFPB, Regulation DD Appendix A: Annual Percentage Yield Calculation.
Worked Examples
Example: $1,000 start, $200 a month, 4.5% APY, 5 years
A 4.5% APY works out to a monthly rate of 0.3675%. The starting balance grows to about $1,246.18. The deposits grow to about $13,398.35. Added together, the ending balance comes to roughly $14,644.53, against $13,000 actually deposited, for about $1,644.53 in interest.
Key Concepts
APY already does the hard math for you: Because it bakes in the compounding effect, comparing two accounts by APY alone is usually enough, without needing to know each bank's exact compounding schedule.
This is a lower-risk counterpart to investing: A savings account trades a lower expected return for FDIC insurance and price stability, which is the opposite trade-off of a market investment.
Most savings APYs are variable: A bank can change its APY at any time, so a five-year projection is a reasonable estimate, not a locked-in guarantee, unless you're using a fixed-rate CD.
Common Mistakes
Confusing APY with APR: APY is what you earn, APR is what you pay to borrow. Using one where the other belongs will throw off any comparison.
Entering a nominal rate as if it were the APY: Since APY already includes compounding, plugging in the pre-compounding rate instead understates how much the account will actually earn.
Assuming the rate is locked in forever: Most savings APYs float with the market and can change without much notice. CDs are the exception, typically locking in a fixed APY along with an early withdrawal penalty.
Frequently Asked Questions
APY, or annual percentage yield, is the total interest an account earns over a year, including the effect of compounding. U.S. banks and credit unions are required to disclose it in a standard way, which makes it the cleanest number for comparing one account against another.
APY is what you earn on a savings account, already including compounding. APR is what you pay to borrow money. For the same nominal rate, APY works out to be equal to or higher than APR, since APY factors in compounding and APR often doesn't.
Use this one for a bank account with a guaranteed, FDIC-insured APY. Use an investment calculator for market-based accounts where the return is variable and not guaranteed, like a brokerage account.
This calculator projects your ending balance based on the deposits you plan to make. A savings goal calculator works in reverse: you enter a target balance, and it tells you the deposit needed to reach it.
Most compound daily and pay out the accrued interest monthly. The advertised APY already accounts for this, so you don't need to work out the daily compounding yourself.
Enter the APY your bank advertises. Because the APY already includes compounding, the calculator converts it down to the monthly rate that grows back to exactly that yield over a year, using i = (1 + APY)^(1/12) - 1. Plenty of savings calculators skip that step and simply divide the APY by 12, which quietly compounds the same figure twice and inflates the result.
Related Calculators
Savings Goal Calculator
Work backward from a target amount to find your required monthly deposit.
Investment Calculator
Use the same math with a market-based, variable return assumption instead of a bank APY.
Compound Interest Calculator
Grow a single lump sum without regular deposits, and compare compounding frequencies.
Interest Rate Calculator
Work backward from a starting and ending balance to find the rate.
Simple Interest Calculator
Calculate straight-line interest with I = Prt, without any compounding.
ROI Calculator
Calculate total and annualized return on a single investment.
401(k) Calculator
Project retirement savings with salary growth, employer match, and IRS limits.