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Deposit Savings Calculator

Calculate how long it will take to save a house deposit based on your monthly savings and interest rate.

Last reviewed 15 August 2026

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Calculator inputs

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When to use this calculator

  • Before choosing between saving, investing or changing a contribution.
  • When you want to compare cautious, base and optimistic return assumptions.
  • When you need a projection before making a longer-term decision.
  • When you want to see whether starting earlier or contributing more changes the outcome more.

A realistic UK planning example

Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.

A realistic UK planning example
InputValue
Target House Price (£)£0.30
Deposit Required (%)£50,000
Current Savings (£)£15,000
Monthly Savings (£)£15,000

After entering these figures, review target deposit and time to save together rather than in isolation. Then rerun the tool with one input adjusted.

How to read your results

Target Deposit

The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.

Time to Save

The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.

Method & assumptionsAuthoritative sources

This calculator shows how a regular monthly contribution, combined with an initial lump sum and assumed interest rate, will grow toward a savings target over time. It applies compound interest, assuming interest is calculated and added monthly, which reflects how most UK savings accounts operate. The Lifetime ISA bonus — where applicable — is not automatically included in the base calculation; you should factor it in separately if you are using a LISA as part of your savings strategy. Inflation is not deducted from the projected total, so the real purchasing power of your savings may be lower than the nominal figure shown if inflation is significant over the period. This tool provides an illustrative projection and should be used alongside advice from a qualified financial adviser for major purchase planning.

Common mistakes

  • !Assuming a constant return without checking a more conservative growth rate.
  • !Forgetting ongoing contributions, fees or tax wrappers where relevant.
  • !Focusing only on the final balance instead of the path required to reach it.
  • !Ignoring the drag of charges over a long period.

What to do next

  • Test a cautious, expected and optimistic growth rate.
  • Compare this result with related savings or retirement tools before committing more money.
  • Consider charges and any tax wrapper that applies.
  • If the projected balance falls short, increase the contribution until the result meets your goal.

Go deeper — 1 guide reference this calculator

Frequently asked

Most lenders require a minimum 5–10% deposit. A 15–25% deposit unlocks the best mortgage rates and is the target for most buyers.

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