Savings Calculator
Project savings account growth with initial deposits, regular monthly contributions, and compound interest.
Savings Projection
Regular deposits, and why the rate is the smaller lever
A savings projection has three inputs — the opening balance, what you add regularly, and the rate. Over short horizons the contributions dominate completely. Saving $500 a month for three years puts in $18,000; at 4% the interest adds roughly $1,100. Chasing an extra half a percent is worth a few pounds a month, while increasing the deposit by 10% is worth ten times that. Rate shopping only starts to pay once the balance is large relative to what you are adding.
That relationship inverts with time. Past roughly a decade the balance grows large enough that returns outpace contributions, and the rate becomes the dominant term. This is the same crossover that makes compound growth feel slow and then sudden — nothing changes in the formula, the balance simply gets big enough for a percentage of it to matter.
Two things a projection will not show. Inflation erodes the real value of the target, so a 4% account against 3% inflation is really growing at about 1%. And taxapplies to interest in most jurisdictions unless the account is sheltered, which can remove a meaningful slice of the return. Where a tax-free wrapper is available, using it is usually worth more than any rate difference between ordinary accounts.
Frequently asked questions
How does monthly deposit saving grow?
Monthly deposits accumulate alongside interest compounded monthly, accelerating portfolio growth exponentially over long horizons.
How much should I be saving each month?
A common benchmark is 20% of after-tax income across emergency savings, retirement and other goals. What matters more than the percentage is consistency and automation - a standing transfer on payday outperforms an intention to save whatever is left at month end.
What is the difference between APY and APR on savings?
APY includes compounding and is what US banks must quote on deposits, so it is the like-for-like comparison. APR excludes compounding and is the lending equivalent. For a savings account, compare APY to APY.
Where should I keep my savings?
Match the account to the time horizon. Money needed within a year belongs somewhere liquid and capital-stable: a high-yield savings account, money market fund or short CD. Money for goals five or more years out can tolerate investment risk. Keeping a long-term goal in cash is its own risk, since inflation erodes it.