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Ledgerly Savings Goal Calculator

How much to save each month for a goal by a date — or how long a monthly amount takes.

ISO code used for the labels, e.g. EUR, USD, GBP.

More options

Gives the month you reach the goal; leave empty to count months only.

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Try an example: · ·

More about this tool

How it works

Works out the monthly amount you need to reach a savings goal by a target date, or how long it takes with the amount you can put aside. Includes what you already have, interest with monthly, yearly or daily compounding, fees and an option to keep the goal in today’s money so it grows with inflation. A small table shows the effect of a higher or lower return. Part of Ledgerly’s Debt & Growth.

  • Each month the balance grows by the monthly rate, the fee (yearly percentage ÷ 12) is taken off, and the monthly amount is paid in at the end of the month.
  • Monthly amount for n months: P = (goal − saved · gⁿ) · (g − 1) / (gⁿ − 1), where g is the monthly growth factor after fees; rounded up to the cent. With no interest P = (goal − saved) / n.
  • Time needed: the balance is simulated month by month until it reaches the goal (at most 100 years).
  • A goal in today’s money grows with inflation every month, so it keeps its buying power.

Interest rates and returns change; recheck the plan every year. Not financial advice.

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How to use the Savings Goal Calculator

Find the monthly amount you need to reach a savings goal by a date, or how long your monthly amount takes, with interest, fees and inflation.

What it is for

Most savings plans start with one of two questions: "How much do I need to put aside each month to have the money by then?" or "I can save this much a month — when will I get there?" This calculator answers either one. You enter the goal, what you have already saved and the interest you expect; then either the number of years (to get the monthly amount) or your monthly amount (to get the time).

You can keep the goal in today's money. Then the goal grows with inflation, so a €30,000 car or deposit still buys the same thing on the day you reach it. A small table shows how the answer changes if the interest is one or two points higher or lower.

Worked example

You want €20,000 in 5 years, have €2,000 saved and expect 3 % interest. Your first saving month is 2027-01.

  • Monthly amount needed: €273.44.
  • Time: 5 years, until 2031-12.
  • You pay in: €18,406.40 (your €2,000 plus 60 × €273.44).
  • Interest and growth: €1,593.83.
  • Monthly amount at other returns: €291.03 at 1 %, €282.17 at 2 %, €264.84 at 4 % and €256.35 at 5 %.

The tool also warns you that in 5 years €20,000 buys only about €18,115 of today's prices at 2 % inflation. If your goal is a price you see today, switch the goal to "Today's money".

Now the other question. You want €30,000 in today's money, have €5,000 and can save €400 a month at 4 %, with 2 % inflation. The tool finds that you get there in 5 years 2 months, when the goal has grown to €33,231.92. You pay in €29,800 and interest adds €3,843.77. At 2 % interest it would take 5 years 6 months, at 6 % only 4 years 10 months.

How to read the result

  • Monthly amount needed (or Goal reached in) is the main answer. The monthly amount is rounded up to the cent, so you really reach the goal.
  • Goal on that date is the goal in the money of that day; it differs from your input only for goals in today's money.
  • You pay in counts your starting amount plus all monthly payments; Interest and growth is the rest.
  • The chart draws your savings and the goal year by year. With a goal in today's money the goal line rises.
  • The table repeats the calculation for returns two points below to two points above yours.

Tips and common mistakes

  • Use a realistic interest rate for where the money will be. Instant-access savings, fixed-term deposits and funds differ a lot.
  • Fill in only the field the mode needs: "Years until the goal" for the monthly amount, "Monthly amount" for the time needed. The other one is ignored.
  • If "Monthly amount needed" is 0, what you already have will grow to the goal by itself.
  • Set yearly fees if the money sits in a fund; they are taken off every month.
  • For a quick holiday fund with no interest, set the return to 0: €3,000 in 18 months is €166.67 a month.

FAQ

When is the monthly amount paid in?

At the end of every month, the same amount each time. What you have already saved earns interest from the first month.

Why does "today's money" make the goal bigger?

Prices rise. A goal in today's money grows with your inflation rate every month, so it keeps its buying power.

What if I never reach the goal?

If the balance stays below the goal for 100 years, the tool says so and shows a warning. Raise the monthly amount or lower the goal.

Can I save several goals?

In Ledgerly you can save one decision per goal and duplicate it as variant B to compare two plans.

Guide last updated:

For scripts and AI agents

  • JSON API: POST https://ledgerlysavingsgoal.usefulweb.app/api/v1/calculate (same calculation as this page)
  • Interface description: OpenAPI 3.1 · AI guide: llms.txt
  • MCP server (Streamable HTTP): https://ledgerlysavingsgoal.usefulweb.app/mcp · tool name ledgerly_savings_goal
Example request
curl -s -X POST https://ledgerlysavingsgoal.usefulweb.app/api/v1/calculate \
  -H 'content-type: application/json' \
  -d '{"currency":"EUR","mode":"monthly-needed","targetAmount":20000,"startAmount":2000,"years":5,"annualReturnPercent":3,"startMonth":"2027-01"}'
Feedback · ideas & bug reports welcome