Free financial calculators

CALCULATORS

Put a number on it.

Choose the question on your mind, then try the numbers for yourself.

Mortgage repayment

The monthly payment on a repayment mortgage, the total interest over the term, and what the whole thing costs.

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Mortgage overpayment

What paying extra each month does to the interest and the term, with early repayment charges accounted for.

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Compound interest

What a starting pot and a regular monthly amount turn into, and how much of the total is growth rather than contributions.

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Retirement shortfall

Where you are, where you want to get to, and the gap between the two in pounds a month.

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Risk reality

If the income stopped tomorrow, how long your own money would hold the line.

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The Lucro tools

Put your own numbers through it.

Each tool is here on the page, so you can move between the decisions that sit together. They are starting points, not advice, but they make a useful first conversation more specific.

Mortgages

What would the monthly payment be?

Put in the borrowing, rate and term to see the payment and total cost.

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Mortgages

What could a little extra do?

See the interest and time that a regular overpayment could take off the mortgage.

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Financial planning

What might the pot grow to?

Explore the effect of time, regular saving and an assumed annual growth rate.

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Financial planning

How close are you to the retirement you want?

See the gap between the pot you may build and the income you have in mind.

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Insurance

How much breathing room is there?

Use a simple view of protection and income resilience to see where a gap might be.

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How these tools work

Use the tools to test the numbers behind a decision. Five use the assumptions you enter; the two pay tools use published 2026/27 rates and thresholds.

Tax rates, thresholds and workplace costs can change. The pay and hiring figures are planning estimates, not exact payroll results.

For an exact tax or payroll calculation, check your circumstances with your payroll provider or HMRC.

How to read any calculator, including ours

A calculation is not a quote.

These figures are estimates, not quotes or personal recommendations. They use the numbers you enter and the assumptions shown for each tool.

Mortgage rates will change over the life of the loan.

The mortgage calculators assume one rate for the whole term. You will remortgage several times, so treat lifetime totals as illustrations of the shape rather than predictions of the number.

Each calculator has its own assumptions.

The compound interest calculator shows growth before charges, tax and inflation. The pay and tax calculators include the taxes and deductions stated in their assumptions. Check the notes beside each tool to see what is included and what is not.

The number still needs context.

Which lender will say yes on your accounts, and whether the money is better in a pension than in the house, are judgement calls. Those are the bits worth a conversation.

Got a number and not sure what to do with it?

Bring the number with you. We can help you work out what it means for the wider decision.

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For employees and business owners

Where does the extra pay go?

Move your income and the figures update straight away. The comparison uses annual PAYE estimates.

2026/27 tax year

Annual gross employment incomeWhere you pay Income Tax

Try a different income

Your positionInside the taper

Below £100kAllowance tapersAllowance gone

What are you already doing?

Add annual amounts. Each route is calculated differently, so only enter contributions that match the descriptions below.

Salary exchanged for pension

Gross salary given up before Income Tax and employee National Insurance.

Workplace pension, net pay

Enter the gross amount deducted from pay before Income Tax. Employee National Insurance is still worked out on pay before this deduction.

Personal pension, relief at source

Enter what leaves your bank. The calculator adds basic-rate relief, so £800 becomes £1,000 gross.

Gift Aid donations

Enter what you donated. A qualifying £800 donation is treated as £1,000 gross for adjusted net income.

Total reduction to adjusted net income£0

Reduction needed to reach £100,000£10,000

Estimated cash left after your entries

£0

about £0 a month

Payroll take-home after claimed tax relief£0

Workplace pension under net pay£0

Personal pension paid£0

Gift Aid donated£0

Adjusted net income£0

Personal Allowance left£0

Income Tax£0

Employee National Insurance£0

Allowance lost£0

You keep £380 of the next £1,000

The other £620 is estimated Income Tax and employee National Insurance while you are inside the taper.

What each pay step changes

This is the bit payslips often make hard to see. Each row compares that salary with the previous £1,000.

Swipe the table sideways to see every column.

Gross income	Cash left after entries	Extra gross	Extra net	Kept from £1	Income Tax + NI

What could reducing adjusted net income change?

Compare four common routes using the remaining gap in your current figures. This explains the mechanics, not what you should do.

Illustrative salary sacrifice route

Reduce adjusted net income by £10,000

That could restore your full Personal Allowance. Whether salary sacrifice or a personal contribution is available depends on your employer and pension.

Salary exchanged£0

Estimated take-home cost£0

Allowance restored£0

Effective relief shown0%

Compare the routes

Same income reduction, different result

The figures below use the amount needed to bring adjusted net income back to £100,000.

Salary sacrifice

Can reduce taxable salary and employee National Insurance where your employer offers it.

Workplace pension

A net pay contribution is deducted before Income Tax, but normally not before employee National Insurance.

Personal pension

The amount you pay is topped up by basic-rate tax relief. You may need to claim further relief.

Gift Aid

The charity receives the basic-rate uplift. It is a donation, so the money does not remain yours.

Illustration only. Tax rates and thresholds can change. This is not a penny-perfect payslip, tax return, financial advice or tax advice. The cash figure assumes any higher-rate pension or Gift Aid relief shown has been claimed, even though it may not arrive through the same payslip. It assumes standard PAYE arrangements and National Insurance category A. It does not model student loans, Child Benefit charges, benefits, tax-code adjustments, dividend rates or every pension rule. Workplace pension schemes can use salary sacrifice, net pay or relief at source, and you should check which method your scheme uses. Pension tax relief is limited by earnings, annual allowance rules and individual circumstances. Gift Aid requires sufficient UK Income Tax or Capital Gains Tax to have been paid. Scotland has different Income Tax bands, which the region selector estimates separately.

Rules used: HMRC Income Tax rates, HMRC adjusted net income guidance, HMRC workplace pension guidance, HMRC pension tax relief guidance, HMRC Gift Aid guidance, and HMRC 2026/27 payroll rates.

Open on its own

Put a number on it.

Mortgage repayment

Mortgage overpayment

Compound interest

Retirement shortfall

Risk reality

Put your own numbers through it.

What would the monthly payment be?

What could a little extra do?

What might the pot grow to?

How close are you to the retirement you want?

How much breathing room is there?

How these tools work

How to read any calculator, including ours

A calculation is not a quote.

Mortgage rates will change over the life of the loan.

Each calculator has its own assumptions.

The number still needs context.

Got a number and not sure what to do with it?

Put a number on it.

What will you actually take home?

What does a new hire really cost?

Where does the extra pay go?

What are you already doing?

Salary exchanged for pension

Workplace pension, net pay

Personal pension, relief at source

Gift Aid donations

What each pay step changes

What could reducing adjusted net income change?

Reduce adjusted net income by £10,000

Same income reduction, different result

Salary sacrifice

Workplace pension

Personal pension

Gift Aid