High-Yield Savings Calculator United States

Cash in a checking account earns almost nothing, and moving it to a high-yield savings account takes little effort: it is an ordinary insured deposit account with no market risk and no lock-up. This calculator projects what a starting balance plus regular monthly deposits grows to at the APY you enter, compounding monthly, and splits the ending figure into the money you put in and the interest earned.

What the projection does

Enter your opening balance, monthly deposit, annual percentage yield and number of years. The tool converts the APY to a monthly rate and advances the balance one month at a time, adding growth and your deposit.

The opening balance compounds for the whole term, while each deposit compounds only from the month it is made, so your first deposit earns for years and your last for a month. The ending balance minus everything you contributed is the interest.

Who sets the rate, and when it moves

A savings rate is set by the bank, which publishes it and changes it when it chooses, with no obligation to follow a benchmark. A money market fund’s yield, by contrast, reflects what its short-term holdings pay, and a Treasury bill’s yield is fixed when you buy it.

Banks tend to compete hard on advertised rates when they want deposits and are slower to keep them high afterward. An account opened at a market-leading rate two years ago may no longer be near the top, and banks do not write to tell you. The calculator’s constant APY is useful for comparing scenarios but is not a forecast; re-run it with your current balance as the starting point when your rate changes.

Also watch for promotional rates that revert after an introductory period, tiered structures that pay the headline yield only above a minimum balance, and caps above which the excess earns much less. All three are common, and none is modeled here.

APY is the number that compares accounts

APY already includes compounding within the year, so it is comparable across accounts that compound daily, monthly or quarterly; the plain interest rate is not. The compounding difference itself is small: most accounts compound daily and credit monthly, and over a five-figure balance across several years the gap with this calculator’s monthly compounding is a few dollars. Move the APY half a point each way to see how much the rate changes your ending balance.

What the insurance covers

FDIC coverage runs to $250,000 per depositor, per insured bank, per ownership category, and credit unions carry equivalent NCUA share insurance. Single accounts, joint accounts, certain trust accounts and retirement accounts are insured separately at the same institution, so a couple can hold considerably more than $250,000 at one bank and stay fully covered. Holding $400,000 in a single-name account at one bank, however, leaves $150,000 uninsured however large the bank is.

Deposits against interest over time

Over a short horizon your own contributions dominate the balance. Over a long one the interest share grows steadily, because each year’s interest is added to the balance that next year’s interest is calculated on. The monthly deposit is usually the input you control most: an automatic transfer on payday raises the balance every month without depending on the bank’s rate.

A five-year example

Open with $10,000, add $200 a month and assume a 4.5 percent APY. Over five years you put in $22,000 in total, and with monthly compounding the balance reaches roughly $25,900, so about $3,900 came from interest with no market exposure. Over ten years the interest share grows much larger.

When a savings account is not the right place

A high-yield savings account suits an emergency fund and money you may need at short notice. Money you are certain not to touch for a fixed period can usually earn more in a certificate of deposit, which locks the rate for the term. Money for goals decades away belongs in invested assets, because a savings rate that only keeps pace with inflation loses ground after tax. Savings interest is taxed as ordinary income at your full marginal rate, not at the lower long-term capital gains rates.

What the projection cannot promise

This is a projection, not a guarantee. It compounds monthly at a constant APY, assumes every deposit is made in full and on time, and shows a pre-tax balance. It does not model expiring promotional rates, tiered or capped rates, minimum-balance requirements, monthly fees or withdrawals. Confirm the current terms of an account before opening it.

About This High Yield Savings Calculator

Use this high yield savings calculator to get an instant estimate based on the figures you enter. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.