Salary & PaySalary Take Home Savings Overtime

Tax year 2026/27 · Rest of UK · annual

UK Savings Calculator

Compound interest growth on monthly savings and lump sums.

Tax year

Region

Schedule

Your details

Monthly deposit

Initial lump sum (optional)

Annual interest rate: 4.00%

4.0%

Years to save

Projected balance

£30,941

Interest earned: £5,941

Breakdown

Total deposited	£25,000
Interest earned	£5,941
Projected balance	£30,941

Interactive scenarios

Tax and deductions, your way

Tax year

Region

Pay schedule

Salary £45,000

Net (monthly)

£2,806

Income tax (monthly)

£541

NI (monthly)

£216

Effective rate

20.2%

Modelled on a 5% pension. Showing monthly figures, rest of UK, tax year 2026/27.

The full guide

Everything worth knowing about Savings

Worked examples with real figures, the rules underneath the number, and the traps that catch people out.

UK Savings Calculator: £200 a month grows to £30,941 in ten years

The UK savings calculator grows a monthly deposit and a lump sum with compound interest and shows the balance, the total you deposited and the interest the money earned. Save £200 a month alongside a £1,000 lump sum at 4% for ten years and the projected balance is £30,941: £25,000 comes out of your own pocket and interest adds the other £5,941.

Interest compounds monthly in the model, and each deposit lands at the end of its month, so growth starts gently and steepens every year you stay invested. The sections below take the two engines of growth, the rate you type, a full worked example and the tax on interest in the order the calculator applies them.

The interest arrives late

The worked example below earns £85 of interest in its first year, £516 in its fifth and £1,160 in its tenth. Each month the interest joins the balance and starts earning interest of its own, so the years you stay invested matter more than the years you spent deciding.

Two engines: the lump sum and the monthly stream

The calculator runs your money through two separate engines and adds the answers. The lump sum compounds by itself from day one, and the monthly deposits form a second stream, each payment compounding for the months it spends inside the pot. Nothing mixes until the final addition, which is why the breakdown can show total deposited and interest earned as clean separate lines.

Compounding runs monthly. The calculator slices the annual rate by 12 and applies that slice to the balance every month, so interest itself earns interest from the following month onward. At 4% the monthly slice is a third of one percent, small enough to look harmless and large enough to add £490.83 to a lone £1,000 across ten years.

Each deposit lands at the end of its month in this model, so a payment made today starts earning interest from the next month rather than today. Real accounts credit interest on their own schedules, daily, monthly or yearly, and a daily interest account edges slightly ahead of this projection on identical inputs because its money starts working a few weeks earlier each time.

The deposit stream does the heavy lifting for most savers. In the worked example the lump sum contributes £1,490.83 of the final balance while the deposits contribute £29,449.96, because £200 arrives 120 times. A saver with no lump sum at all still reaches £29,449.96 on the same settings, while the lump sum alone, with no deposits, reaches only £1,490.83.

Watch the balance at the halfway mark to feel the shape of the curve. After five years the same savings stand at £14,480.79, with £1,480.79 of interest inside it. The second five years then add £4,460 of interest, three times what the first five managed, on exactly the same monthly payment.

Stretch the term and the balance between the engines shifts. Across twenty years the same settings deposit £49,000 and finish at £75,577.51, so interest supplies £26,577.51, over a third of the final pot. The lump sum engine reaches £2,222.58 by then, still small beside the deposit stream, but the interest share of the whole pot has nearly doubled from its ten year level.

The rate you type: a yearly label, applied monthly

The rate box asks for an annual figure, and the calculator applies it as a monthly slice, one twelfth at a time. Entering 4% therefore grows money at an effective 4.07% across a full year, because each monthly slice compounds on the slices before it. The gap between the typed rate and the effective rate is small at savings account levels and grows as the rate itself rises.

AER exists to cut through exactly this. An account quoting an AER has already folded its own compounding into the number, whichever schedule it credits interest on, so AER figures compare cleanly against each other while headline rates paid on different schedules do not. Compare accounts on AER, and enter the figure here knowing this calculator applies monthly compounding of its own to whatever you type.

Rate moves matter, and the worked example prices them. Hold every other input steady and change only the rate: at 2% the balance finishes at £27,765.13 with interest of £2,765.13, and at 5% it finishes at £32,703.47 with interest of £7,703.47. A single point of rate across ten years is worth roughly £1,760 on these deposits, in either direction.

The slider runs from 0% to 10%, and the bottom end earns its place. At a zero rate the projection collapses to pure deposits, £25,000 on the example figures, which gives you the honest baseline every interest figure should be measured against: growth above that line is the only part the account itself contributed.

Worked example: £200 a month and a £1,000 lump sum at 4%

Take the starting figures on the page, in the order the calculator builds them: £200 a month, a £1,000 lump sum, a 4% annual rate and ten years. The calculator converts the rate to a monthly slice, 4% divided by 12, and compounds that slice across 120 months.

The lump sum grows on its own first. £1,000 compounded monthly at that slice reaches £1,490.83, so the lump earns £490.83 without a single deposit touching it.

The deposits build the second stream. One hundred and twenty payments of £200 put £24,000 in, and compounding lifts the stream to £29,449.96, which is £5,449.96 of interest on the deposits alone.

Add the two streams and the calculator lands on its three answers. Total deposited is £25,000, interest earned is £5,940.79, and the projected balance is £30,940.79, which the page rounds to £30,941. Interest builds almost a fifth of the final pot, and none of it was money you handed over.

Tax on interest: the £1,000 personal savings allowance

The projection above is gross. The calculator adds every penny of interest the balance earns and leaves tax out of the result, and its own note on this page states the relief most savers rely on: basic rate taxpayers earn £1,000 of interest tax free each year under the personal savings allowance.

The allowance covers the interest you earn in a tax year, not the size of the pot. The worked example stays comfortably inside it for most of its life, earning £85 of interest in year one and £516 in year five. By year ten the balance earns £1,160 of interest in a single year, which passes the £1,000 line on its own, so a basic rate saver holding this pot in an ordinary taxable account would owe tax on the slice above the allowance that year.

Two further reliefs sit outside this calculator and change the position for many savers. Higher rate taxpayers work with a smaller personal savings allowance and additional rate taxpayers get none, a separate starting rate for savings can shelter interest for people whose other income is low, and interest inside an ISA is never taxed at all. The calculator models none of those routes, so run the gross figure here and then test your own tax position against it.

The practical order follows from that. Fill the tax free shelters first and let this calculator price the money that has to sit in a taxable account, because the same £200 a month produces the same gross projection in both places and a different spendable one.

What this calculator leaves out

The rate never moves. Real savings rates rise and fall with the market, accounts reprice, and a fixed rate deal ends and rolls onto whatever follow on rate the provider offers. The projection is the path at the rate you typed from the first month to the last, so rerun it whenever your account changes its rate and treat the answer as a snapshot rather than a promise.

The deposits never move either. The model takes the same payment every month for the full term, with no missed months, no top ups and no withdrawals. One withdrawal early in the term costs more than its face value, because the money taken out stops compounding for every month that remains.

Inflation stays outside the frame. The end balance is a nominal figure, future money rather than today's spending power. A saver who wants the real terms answer can rerun the projection with expected inflation subtracted from the account rate and read the balance as today's money instead.

Set the levers against each other before you leave the page. On the worked example, adding £100 a month lifts the ten year balance to £45,665.77, while a whole extra point of interest rate lifts it only to £32,703.47. The deposit is the lever you control and the rate is the lever the market controls, and the calculator prices both honestly.

Introductory rates hide a second run of the calculator. An account paying a bonus rate for its first year and a plain rate afterwards follows two different projections, and the honest way to model it here is to run the term in two pieces: the bonus period at its rate, then the remaining years at the standard rate, carrying the first balance into the second run as its lump sum.

Where the UK Savings Calculator gets its figures

Rates, bands and thresholds follow published HMRC and gov.uk figures for the 2026/27 tax year, held in one table that every tool reads. April arrives, the table changes, and the results move together.

Earlier years stay available through the year selector, so a late self assessment runs on the numbers that applied at the time rather than today's.

Some cases still need an accountant. K codes carrying negative allowances, bespoke sacrifice arrangements, the annual allowance taper for very high earners, and anything involving two employments at once.

About this calculator

The UK Savings Calculator shows how your money grows with compound interest. Enter a monthly deposit, an initial lump sum, the annual interest rate and the number of years to see your projected balance, total deposits and interest earned.

Frequently asked questions

How does compound interest work?+

Compound interest means you earn interest on your interest, not just your deposits. Each month the interest is added to your balance, so the next month's interest is calculated on a slightly bigger pot — growth accelerates over time.

How much interest will I earn on £10,000 over 5 years?+

At 4% annual interest compounded monthly, £10,000 grows to about £12,210 over 5 years, earning roughly £2,210 in interest. Enter your own figures above to see an exact projection for your situation.

Is monthly or annual compounding better?+

Monthly compounding is slightly better because interest is added to your balance twelve times a year instead of once, so it starts earning its own interest sooner. Most UK savings accounts compound monthly or daily.

Do I pay tax on savings interest in the UK?+

It depends. Basic-rate taxpayers get a £1,000 personal savings allowance of tax-free interest per year (£500 for higher-rate taxpayers). Interest inside a cash ISA is always tax-free regardless of the amount.

Should I save in a regular account or an ISA?+

If you are likely to earn more interest than your personal savings allowance, an ISA shelters it from tax completely. Within the £20,000 annual ISA allowance, a cash ISA at the same rate always beats a taxable account.

What is a realistic interest rate for UK savings in 2026?+

Easy-access accounts typically pay around 3–4% while fixed-term accounts can reach 4–5%, depending on Bank of England base rate moves. Use the slider above to model best and worst cases for your plan.

How much should I save each month?+

A common rule is 20% of take-home pay, but any consistent amount works because compounding rewards time more than size. Even £200 a month at 4% grows to over £36,000 in 10 years including interest.