Planning backwards from a goal
Most calculators tell you what you’ll have if you save a certain amount. This one flips the question: you know the target, so it tells you what it takes to get there. That’s the more useful direction when you’re saving for a deposit, a wedding, a sabbatical, or an emergency fund.
Solving for the contribution
PMT = (Goal − P₀·(1 + i)n) ÷ (((1 + i)n − 1) ÷ i)
where P₀ = current savings, i = monthly return, andn = months. It subtracts what your existing savings will grow into, then spreads the rest across the future contributions.
What makes this calculator different
- Two questions, one tool. Solve for the monthly amount you need, or for how long your current pace will take — your choice.
- Inflation-honest goals. Express your target in today’s money and we inflate it to the target date, so the pot you build keeps its real buying power.
- Your head start counts. Existing savings keep compounding, and the plan reflects exactly how much they reduce what you need to add.
- See and share the path. A projection chart with your goal line, an exportable year-by-year table, and a shareable link.
Frequently asked questions
How much do I need to save each month to reach my goal?+
Switch the calculator to “Monthly amount”, enter your target, what you’ve already saved, your time horizon, and an expected return. It solves for the exact monthly contribution that lands you on your goal — taking the growth of both your starting balance and your future contributions into account.
How long will it take to reach my goal?+
Switch to “Time to goal” and enter how much you can save each month. The calculator simulates your balance forward month by month and tells you when it crosses your target. A bigger monthly amount or a higher return gets you there sooner.
What does “goal is in today’s money” mean?+
A £100,000 goal 20 years from now won’t buy what £100,000 buys today. Tick this box and the calculator inflates your target to the future date, so the pot you build actually has the buying power you intended. It’s the difference between a goal that feels right and one that genuinely is.
Why does the required amount drop when I add current savings?+
Money you’ve already saved keeps compounding for the whole period, doing some of the work for you. The more you start with, the less you need to add each month — and the calculator shows exactly how much less.
What return rate should I assume?+
It depends on where you save. Cash and high-yield savings might return a few percent; a diversified long-term investment portfolio has historically returned more but with risk and no guarantees. Try a conservative and an optimistic figure to see the range — and remember these are estimates, not promises.
Disclaimer: This calculator is for educational purposes only and assumes a constant rate of return, which real markets never provide. It is not financial or investment advice.