About this calculator
Every savings goal — an emergency fund, a house deposit, a car, a wedding — is really three numbers: the target, what you already have, and what you can add each month. This calculator adds the fourth number everyone forgets, the interest the account itself pays, and tells you when you arrive. Watching the date move closer when you raise the monthly amount by even $25 is the most motivating arithmetic in personal finance.
The interest rate matters more than people expect over long horizons. At 4% (a typical high-yield savings rate in recent years) a decade of saving earns thousands in interest; in a 0.01% big-bank account it earns almost nothing on the same contributions.
How to use it
- Enter your target amount.
- Enter what you have already saved toward it.
- Enter a monthly contribution you can sustain on your worst month, not your best.
- Enter the rate your account actually pays — check your bank app, it is often lower than you think.
The formula
Like the amortization calculation in reverse, the calculator walks the balance forward month by month, crediting interest and adding your contribution, and reports the first month the goal is reached. The closed-form equivalent uses logarithms, but the month-by-month walk is exact and easier to trust.
Worked example
Saving toward $50,000 with $5,000 already set aside, adding $300 a month at 4%: you arrive in 117 months — 9.75 years — with a final balance of $50,222.20. You contributed $40,100 in total; the other $10,122.20 is interest the account paid you. Raising the contribution to $400 a month pulls the finish line in by roughly two years.
Frequently asked questions
How much should I keep in an emergency fund?
The standard guideline is 3–6 months of essential expenses — rent, food, insurance, minimum payments. People with variable income, a single income supporting a family, or specialized jobs often target more. Keep it in a high-yield savings account: liquid, insured, and earning something.
Where should I keep money I am saving for a goal?
Match the account to the timeline. Money needed within about two years generally belongs in savings (high-yield accounts or short CDs), not investments — a market dip at the wrong moment can delay the goal. Longer goals can reasonably be invested, accepting ups and downs for higher expected returns.
Should I save or pay off debt first?
Compare rates. If a credit card charges 22% and savings pay 4%, paying the card is a guaranteed 22% "return" — debt first, keeping only a small starter emergency fund (often $1,000–$2,000) while you attack high-interest balances. Low-rate debt (a cheap mortgage) usually loses to saving and investing.
How do I find my account's real interest rate?
Look for "APY" in your bank app or statements. Many traditional savings accounts pay 0.01%–0.1%, while high-yield online accounts have paid around 4%–5% in recent years. On $20,000 that gap is the difference between $2 and $800+ of interest a year.