Money Market Account Calculator — Tiered APY & Growth

Calculate money market account growth with tiered APY rates and monthly contributions. See exactly how balance tiers blend into your effective rate.

July 5, 2026

Initial Deposit ($)

Monthly Contribution ($, optional)

Term (years)

APY (%)

Ending Balance (3.30% APY)

$26,677.22

$25,000 contributed + $1,677.22 interest earned

Assumes monthly compounding, with contributions added at the end of each month. The federal Reg D rule that limited savings and money market accounts to 6 "convenient" withdrawals or transfers per month was suspended by the Federal Reserve in April 2020 — it's no longer a federal requirement, though many banks still enforce their own version of this limit and may charge excess-transaction fees, so check your specific account's policy. Actual results will differ if your bank's rate or tier structure changes during your term.

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Reference Values

Last verified: Jul 5, 2026

Category	Range	What It Means	Status
Money Market Account (MMA) ★	≈3.0%–3.9% APY (top-tier, mid-2026)	Variable rate, often tiered by balance (higher balances unlock a higher APY). Usually includes check-writing and/or a debit card. Historically capped at 6 "convenient" transactions/month under Reg D — that federal cap was eliminated in 2020, but many banks still enforce their own version and may charge excess-transaction fees.	★ Best
High-Yield Savings Account (HYSA)	≈4.0%–4.5% APY (top-tier, mid-2026)	Variable rate, typically a single flat APY regardless of balance (no tiers). No check-writing or debit card access — transfers only. Same voluntary 6-withdrawal norm as MMAs at many banks.	Good
Certificate of Deposit (CD)	≈4.0%–4.5% APY (top-tier, 1-year term, mid-2026)	Fixed rate locked for the full term — doesn't move if market rates fall (or rise). No withdrawals without an early withdrawal penalty, since funds are locked until maturity.	Good
Traditional savings account (national average)	≈0.58% APY (mid-2026)	The FDIC-tracked national average — roughly 5–7x lower than a top-tier MMA or HYSA for identical FDIC insurance protection.	Poor
Reg D transaction limit — history	6 transfers/withdrawals per month (pre-April 2020); no federal limit since	The Federal Reserve's Regulation D officially capped "convenient" transfers and withdrawals from savings and money market accounts at 6 per month for decades. An interim final rule effective April 24, 2020 removed this federal requirement entirely. Many banks still voluntarily cap monthly transactions at 6 and may charge an excess-transaction fee — this is now a bank policy choice, not a federal rule.	Okay
FDIC/NCUA insurance (all three account types) ★	$250,000 per depositor, per institution, per ownership category	Identical protection for MMAs, HYSAs, and CDs as long as the institution is FDIC-insured (or NCUA-insured for credit unions) — a higher rate does not mean higher risk.	★ Best

Source: Federal Reserve Regulation D interim final rule (effective April 24, 2020, docket R-1660); FDIC National Rates and Rate Caps (national deposit rate averages); Bankrate money market account rates methodology; NerdWallet Regulation D explainer. Individual bank rates, tier breakpoints, and transaction policies vary — always confirm current terms directly with your bank before opening an account.

Worked Examples

Single-Tier, Lump Sum Only

Initial Deposit: $50,000
APY: 3.50%
Monthly Contribution: $0
Term: 2 years

$53,561.25 ending balance

Monthly compounding at a flat 3.50% APY for 24 months grows $50,000 to $53,561.25 — $3,561.25 in interest earned with no added contributions.

Single-Tier, With Monthly Contributions

Initial Deposit: $10,000
APY: 3.75%
Monthly Contribution: $300
Term: 3 years

$22,569.17 ending balance

Over 36 months, the $10,000 initial deposit plus $300/month ($10,800 in contributions) totals $20,800 contributed. With monthly compounding at 3.75% APY, the balance grows to $22,569.17 — $1,769.17 in interest earned on top of what was deposited.

Tiered-Rate, Lump Sum Above the Threshold

Initial Deposit: $1,500,000
Tier 1: 3.09% up to $1,000,000
Tier 2: 3.64% above $1,000,000
Monthly Contribution: $0
Term: 1 year

$1,549,180.44 ending balance (blended ≈3.27% APY)

$1,000,000 earns 3.09% and the remaining $500,000 earns 3.64%, blending to an effective ≈3.273% APY on the full balance. Over 12 months that grows $1,500,000 to $1,549,180.44 — $49,180.44 in interest.

Tiered-Rate, Contributions Push the Balance Into a Higher Tier

Initial Deposit: $900,000
Tier 1: 3.09% up to $1,000,000
Tier 2: 3.64% above $1,000,000
Monthly Contribution: $50,000
Term: 6 months

$1,215,859.54 ending balance

Starting below the $1M threshold, the account earns 3.09% for the first two months. By month 3 the growing balance crosses $1,000,000 and the effective blended rate starts climbing toward 3.64% as more of the balance sits in the top tier — the calculator re-checks the tier every month rather than locking in one rate for the whole term. $900,000 plus $50,000/month for 6 months ($1,200,000 contributed) grows to $1,215,859.54, or $15,859.54 in interest.

Three-Tier Structure, Smaller Balance

Initial Deposit: $50,000
Tier 1: 2.50% up to $10,000
Tier 2: 3.20% $10,000–$100,000
Tier 3: 3.90% above $100,000
Monthly Contribution: $500
Term: 1 year

$57,618.46 ending balance (blended 3.06% APY at start)

At a $50,000 starting balance, $10,000 earns 2.50% and the remaining $40,000 earns 3.20%, blending to 3.06% APY at the start. With $500/month added for 12 months ($56,000 contributed), the balance grows to $57,618.46 — $1,618.46 in interest, without ever reaching the top 3.90% tier in this example.

How to Use This Calculator

1

Enter your initial deposit and term

The lump sum you're starting with and how long you plan to hold it, in years.
2

Choose Single APY or Tiered-Rate mode

Use Single APY for a flat-rate account, or Tiered-Rate if your bank pays a higher APY above certain balance thresholds.
3

Enter your bank's rate tiers (if applicable)

Set the balance threshold(s) and the APY for each tier — up to 3 tiers supported. The calculator blends the effective rate automatically.
4

Add a monthly contribution (optional)

Enter a recurring monthly deposit if you plan to keep adding to the account, or leave at 0 for a lump-sum-only projection.

What Each Value Means

Blended APY (percent (%)): The single effective interest rate that results from averaging two or more tiered rates, weighted by how much of your balance sits in each tier. Recalculated monthly as your balance grows across thresholds.
Ending Balance ($): The total amount (principal + contributions + earned interest) in the account at the end of the term you entered.
Interest Earned ($): The portion of the ending balance that came from compounding, separate from your initial deposit and any monthly contributions.

Frequently Asked Questions

How is money market account interest calculated with tiered rates?

Each portion of your balance earns the APY for the tier it falls into, then those pieces blend into one effective rate — similar to how tax brackets work. For example, with a 3.09% APY up to $1,000,000 and 3.64% above that, a $1,500,000 balance earns 3.09% on the first $1,000,000 and 3.64% on the remaining $500,000, blending to about 3.27% on the full balance. This calculator re-checks which tier your balance sits in every month, so the effective rate shifts automatically as contributions push you across a threshold.

What's the difference between a money market account, a CD, and a high-yield savings account?

All three pay compound interest and are typically FDIC-insured up to $250,000, but they differ in structure. A CD locks in a fixed rate for a set term with an early withdrawal penalty if you need the money sooner. A high-yield savings account (HYSA) usually pays one flat APY regardless of balance, with no check-writing. A money market account (MMA) often pays a tiered APY that rewards larger balances, and usually comes with check-writing and/or debit card access that a HYSA doesn't offer — at the cost of typically needing a higher minimum balance to earn the top rate.

Is the 6-transaction-per-month limit on money market accounts still a federal rule?

No. Regulation D used to cap "convenient" transfers and withdrawals from savings and money market accounts at 6 per month, but the Federal Reserve's interim final rule, effective April 24, 2020, removed that federal requirement entirely. It's no longer a law. However, many banks kept a similar limit as their own account policy and may still charge an excess-transaction fee if you go over — so check your specific bank's current terms, since this is now a business decision rather than a regulation.

Do I need a large balance to open a money market account?

It depends on the bank. Some money market accounts have no minimum balance requirement at all, while others require anywhere from a few hundred to several thousand dollars to open the account or to avoid a monthly maintenance fee — and separately, many use tiered APY structures where you need a much larger balance (often $25,000, $100,000, or more) just to unlock the top advertised rate. Always check both the account-opening minimum and the rate-tier thresholds before assuming you'll earn the headline APY.

Are money market accounts a safe place to keep savings?

Yes, as long as the account is at an FDIC-insured bank (or NCUA-insured credit union), your money market account balance is protected up to $250,000 per depositor, per institution, per ownership category — identical protection to a regular savings account or CD. A money market account is not the same thing as a money market mutual fund, which is an investment product that isn't FDIC-insured and can (rarely) lose value; always confirm you're opening a bank deposit account, not a fund, if federal deposit insurance matters to you.