Free Savings Goal Calculator (Monthly, Weekly, Per Paycheck)

Guide by Kepler Oates · Updated Oct 22, 2026

What this calculator is for

Most savings goals fail for a simple reason: "save for a trip" is a wish, while "move $84.58 every Friday" is a plan. This calculator turns a goal and a date into the exact amount to set aside.

You enter what you are saving for, the goal amount, what you have already saved, the month you want to reach it, and, if you like, the interest rate on your savings. The tool shows how much to save each month, each week and every 2 weeks, plus how many months you have left.

How the math works

Without interest

If you leave the interest box at 0, the math is simple:

Monthly amount = (goal − already saved) ÷ months left

Months left is the number of calendar months from now until the month you picked. If it is October and you choose October next year, that is 12 months.

With interest

If you add a rate, the calculator assumes interest compounds monthly at the yearly rate ÷ 12, and that you deposit at the end of each month. Two things grow toward your goal:

What you already have grows to: saved × (1 + r)^n.
Your monthly deposits grow as a series, so each month needs a little less.

The tool solves for the monthly deposit:

Monthly = (goal − saved × (1 + r)^n) × r ÷ ((1 + r)^n − 1)

where r is the monthly rate and n is the number of months.

Weekly and every-2-weeks amounts

These are the monthly amount spread across the year:

Each week = monthly × 12 ÷ 52.
Every 2 weeks = monthly × 12 ÷ 26.

The every-2-weeks figure suits people paid biweekly. There are 26 paychecks in a year, so a couple of months have three, which is why it isn't simply half the monthly amount.

Worked example

Example numbers only: a $5,000 trip fund, $500 already saved, 12 months to go, and a savings account paying 4% a year.

Monthly rate: r = 4 ÷ 100 ÷ 12 = 0.0033333.
Growth factor: (1 + r)^12 = 1.040742.
Your $500 grows to 500 × 1.040742 = $520.37.
Still needed from deposits: 5,000 − 520.37 = $4,479.63.
Monthly: 4,479.63 × 0.0033333 ÷ 0.040742 = $366.51.
Each week: 366.51 × 12 ÷ 52 = $84.58.
Every 2 weeks: 366.51 × 12 ÷ 26 = $169.16.

Without interest, you would need (5,000 − 500) ÷ 12 = $375.00 a month. Interest trims about $8.49 a month here. That's helpful, but over a short goal your own deposits do almost all the work.

How to read your results

Save each month: the main number. Set it as an automatic transfer.
Each week / Every 2 weeks: the same plan sized for how you are paid.
Months left: the time you have, counted in calendar months.
The message: a one-line summary using your goal's name, and a note if interest is included.

If what you have already saved will reach the goal on its own, the tool shows $0 and tells you so. If you pick a month that is not at least one month away, it asks you to choose a later date.

Common mistakes

Choosing a date that is too close. A plan you cannot afford gets abandoned. Push the date out and watch the monthly amount drop.
Using an optimistic interest rate. Savings rates change. Use your account's current rate, or leave it at 0 for a cautious plan.
Forgetting the extras. Trips have fees, gadgets have accessories, moves have deposits. Build them into the goal amount.
Saving whatever is left over. Leftovers tend to disappear. Move the amount first, on payday.
Mixing goal money with spending money. A separate account, or at least a named sub-account, makes progress visible.

Practical tips

Match the frequency to your paycheck: weekly, every 2 weeks or monthly.
Name the goal. "Trip fund" or "New laptop" is easier to protect than a number.
Check in once a month. If you fall behind, update "Already saved" and the tool recalculates what is needed from here.
Running several goals? Use the tool once per goal and add the monthly amounts to see if the total fits.
Your figures stay in this browser, and Print / save PDF keeps a copy.

Doing the work

A goal turns real when you take the first small action, today. Set the transfer, then record it, much like the Receipt that ends each day in the workbook. If you haven't built a safety net yet, start with the Emergency Fund Calculator. For longer horizons, the Compound Interest Calculator shows how growth adds up over years.

This is general information, not financial advice.

Frequently asked questions

How much should I save each month to reach my goal?

Subtract what you have already saved from your goal, then divide by the number of months until your target date. If your savings earn interest, you need slightly less, and this calculator works that out for you. For a $5,000 goal with $500 saved and 12 months to go, that is $375 a month without interest, or about $366.51 at an example 4% rate.

How do I calculate a weekly savings amount?

Multiply the monthly amount by 12 to get a yearly total, then divide by 52 weeks. The calculator shows this as the "Each week" figure. Saving weekly can feel easier because each amount is smaller and lines up with weekly pay.

Why is the every-2-weeks amount not half of the monthly amount?

There are 26 two-week periods in a year, not 24, so a couple of months contain three paychecks. The calculator spreads the yearly total across 26 deposits, which makes each one a bit less than half the monthly amount. It suits people who are paid biweekly.

Does interest make a big difference for short savings goals?

Over a year or two, usually not much, because there is little time for growth. In our example, 4% interest trims the monthly amount from $375.00 to about $366.51. Your regular deposits do most of the work on short goals, while interest matters more over many years.

What if I fall behind on my savings plan?

Update the "Already saved" amount to what you actually have and the calculator recalculates the monthly amount needed from now. If the new figure is too high, consider moving the target date later or adjusting the goal. A plan you can keep is better than an ambitious one you abandon.

Savings Goal Calculator

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