Savings Goal Planner: How Long to Reach £X?
Set a target, add monthly contributions and any lump sums, and estimate the time to reach your goal. We also show how inflation changes the “real” value of your target over time.
1) Define Your Goal and Timeline
Start with a clear target (e.g., “£15,000 for a car in 24 months”). Decide whether the deadline is fixed (you must hit it by a date) or flexible (you’re willing to extend it as needed). Then choose your contribution plan: a regular monthly amount, possible one-off lump sums, and any expected annual top-ups (bonuses, tax refunds).
2) The Core Maths
With monthly compounding and a fixed monthly deposit, the future value after n months is:
FV = P·(1+i)n + C · [((1+i)n − 1) / i]
- P = starting balance (including any immediate lump sum)
- C = monthly contribution
- i = monthly rate (AER ÷ 12, as a decimal)
- n = number of months
To solve “how long to reach £X?”, iterate months until FV ≥ Goal. Our Savings Growth Calculator does this for you.
3) Lump Sums vs Monthly Payments
Lump sums have the biggest effect when added early — they compound for longer. Regular contributions build steady momentum and are easier to budget. Many savers combine both: a starter lump sum plus an automated monthly transfer.
4) Inflation: Nominal vs Real Targets
Inflation erodes purchasing power. If your goal is £20,000 in “today’s money” and inflation is 3% a year, the future nominal target in 3 years is roughly £21,855. To compare apples to apples, deflate your future value back to today’s terms:
Real FV ≈ FV / (1+π)t, where π is annual inflation and t is years.
Example: You’ll save £400/month at 4% AER. Starting from £0, you’ll reach £10,000 in ≈ 24 months nominally. At 3% inflation, that’s ≈ £9,420 in today’s money.
5) Practical Levers to Reach Goals Faster
- Automate payday transfers: “Pay yourself first” before spending happens.
- Round up contributions: If you can do £180, try £200 — small bumps compound.
- Channel windfalls: Bonuses, tax rebates, and gifts go straight to the goal.
- Lock the pot: Consider fixed-term or notice accounts for better AER if you don’t need instant access.
- Minimise fees & leakage: Avoid penalty charges and keep the account fee-free.
6) Tracking That Actually Works
- Use a simple monthly tracker (spreadsheet/app). Tick off each deposit.
- Show both nominal and inflation-adjusted progress to stay realistic.
- Set milestones (25%, 50%, 75%) and celebrate each step.
- Review contributions after pay rises or bill changes.
7) Worked Scenario
| Inputs | Value |
|---|---|
| Target | £12,000 |
| Start balance | £1,000 |
| Lump sum (month 0) | £1,500 |
| Monthly deposit | £250 |
| AER | 4.0% |
| Inflation | 3.0% |
Time to goal (nominal): about 35–37 months depending on compounding day. In today’s money, the goal is ~£13,100 by then — so you may either increase deposits slightly or accept a little extra time.
8) Key Takeaways
- Combine a starter lump sum with automated monthly deposits.
- Inflation matters — view progress in both nominal and real terms.
- Small increases and windfalls meaningfully cut time to goal.
- Model your plan in the Savings Growth Calculator and adjust quarterly.