Hundred Summers

Free calculators

Free, no sign-up, no data collected — the calculators run entirely in your browser, powered by the same engine as the full Hundred Summers plan. Education, not advice.

What do you want to work out?

Start from a question: each route takes the calculators in the order you would need them.

Understand my moneyBudget, net worth, a cash cushion, debt and pay.
  1. What's left over each month?Household budget calculator
  2. What do I own, and how much can I reach?Net worth calculator
  3. Is my cash cushion big enough?Emergency fund calculator
  4. Which debt should I clear first?Debt payoff calculator
  5. What does my pay come to after tax?Take-home pay calculator
  6. Is my tax code right?Tax code checker
  7. Am I keeping all my child benefit?Child benefit calculator
  8. What is inflation doing to my money?Inflation calculator
Then put it together: the full plan connects every step, year by year.
Grow my wealthSaving, investing, pensions, tax wrappers and charges.
  1. What will regular saving grow to?Savings growth calculator
  2. ISA or pension for the next pound?ISA vs pension calculator
  3. How much tax would I pay investing outside an ISA?ISA vs general investment account
  4. What does a pension contribution really cost?Pension tax relief calculator
  5. How much would salary sacrifice save?Salary sacrifice calculator
  6. Is a Lifetime ISA worth it?Lifetime ISA calculator
  7. What are charges costing me?Fund charges calculator
  8. Premium Bonds or a savings account?Premium Bonds calculator
Then put it together: the full plan connects every step, year by year.
Make a big purchaseBuying a home, moving, borrowing and remortgaging.
  1. How long will a deposit take to save?House deposit calculator
  2. How much could I borrow?Mortgage affordability calculator
  3. What will the stamp duty be?Stamp duty calculator
  4. What will the mortgage cost each month?Mortgage repayment calculator
  5. Is buying better than renting for me?Rent vs buy calculator
  6. Is it worth switching mortgage?Remortgage calculator
  7. Overpay the mortgage or invest?Mortgage overpayment calculator
  8. What would a car or personal loan really cost?Loan repayment calculator
Then put it together: the full plan connects every step, year by year.
Plan my futureRetirement, stopping work early, the children, and the years ahead.
  1. How much do I need to retire?
  2. When could I stop work?When can I retire?
  3. What will my pension be worth?Pension projection calculator
  4. Could I be financially independent early?FIRE calculator
  5. How would I fund the years before my pension?ISA bridge calculator
  6. What if markets crash as I retire?Retiring into a market crash
  7. Take the tax-free cash now or later?Tax-free cash: now or later
  8. How should I save for my children?Junior ISA vs junior pension
Then put it together: the full plan connects every step, year by year.
Protect my familyInsurance, illness, redundancy, care and inheritance.
  1. What are the real odds of illness or death before retirement?Risk reality calculator
  2. How would we cope if I couldn't work?Income protection calculator
  3. How much life cover do we need?Life insurance calculator
  4. What would a serious illness cost us?Critical illness cover calculator
  5. What would redundancy pay me?Redundancy pay calculator
  6. Who pays if I need a care home?Care home means test calculator
  7. Will my estate pay inheritance tax?Inheritance tax calculator
  8. Who would inherit if I had no will?Who inherits without a will
Then put it together: the full plan connects every step, year by year.
Plan as a coupleA joint budget, unequal incomes, children, retiring together and what the survivor keeps.
  1. What's left over between us each month?Household budget calculator
  2. Can we share an unused personal allowance?Marriage allowance calculator
  3. What would going part-time really cost?Part-time work calculator
  4. What will parental leave pay?Maternity and paternity pay calculator
  5. How much help with childcare do we get?Tax-Free Childcare calculator
  6. Can we both retire when we want, and what if one of us dies?Couples retirement calculator
  7. What would the survivor keep from a pension?Inherited pension calculator
  8. What would our estate pay?Inheritance tax calculator
Then put it together: the full plan connects every step, year by year.
Would your retirement have survived 1929?
Replay your pot and spending through every real market sequence since 1928 and watch each history unfold.

Retirement planning

11
Will the money last, when can you stop, and what the standards say a retirement costs.
Pension drawdown calculator
How long your pot lasts, and what you could sustainably spend.
When can I retire?
The earliest age your savings fund every retirement year.
Couples retirement calculator
Can we both retire when we want, and what would the one left have?
How much do I need to retire?
The pot you need, solved year by year with tax and the State Pension.
Safe withdrawal rate calculator
Your personal withdrawal rate, solved with UK tax and the State Pension.
Retiring into a market crash
1929, 1966, 1973, 2000, 2008 and 2022 replayed from the year you retire.
Retirement Living Standards checker
Minimum, moderate or comfortable: your income after tax against the standards.
FIRE calculator
Your Lean, Regular and Fat FI numbers and the age each arrives.
ISA bridge calculator
Whether your ISA can carry the years before pension access.
Annuity calculator
The guaranteed lifetime income a pot could buy, with the options priced.
Life expectancy calculator
How long to plan for, from ONS data with a buffer.

Pensions

13
Contributions, allowances, the State Pension and the tax on taking money out.
Pension projection calculator
Your pot at retirement in today's money, net of charges.
Pension income tax calculator
How much of your State and private pension income is tax.
Pension tax relief calculator
What a contribution really costs after 20% at source and higher-rate relief.
Salary sacrifice calculator
Income tax and NI saved by sacrificing salary into your pension.
ISA vs pension calculator
The same slice of pay saved two ways, compared at your rates.
Pension carry-forward calculator
How much you can pay in this year using three years' unused allowance.
Tapered annual allowance calculator
Threshold and adjusted income, your pension allowance, and any charge.
Tax-free lump sum calculator
All 25% up front, or a slice of every withdrawal: which pays.
Tax-free cash: now or later
Take the pension lump sum into an ISA, or leave it: for you and your heirs.
Pension emergency tax calculator
The over-taxed first withdrawal, what is really due, and how to reclaim it.
State Pension deferral calculator
What deferring adds, what waiting costs, and the breakeven age.
Voluntary NI calculator
Whether buying a missing National Insurance year pays back.
Defined benefit early retirement calculator
A final salary pension taken early: the reduction and the breakeven age.

Pay and tax

19
What you keep, and the cliffs and traps in the UK tax system.
Take-home pay calculator
Income tax, NI and student loan on your salary, and your true marginal rate.
Tax code checker
What your tax code means, the tax it takes against the tax you owe, and a rough refund.
60% tax trap calculator
The pension contribution that gets you back to £100,000, and what it really costs.
Part-time work calculator
What a four-day week really costs in take-home, pension and benefits.
Company car tax calculator
What a company car costs you in tax, and whether free fuel is worth it.
Bonus tax calculator
Where a bonus goes, and what sacrificing it into your pension keeps.
Self-employed tax calculator
Income tax and Class 4 NI on your profits.
Sole trader vs limited company
The same profit taken both ways, every line shown, the difference stated.
Contractor take-home: inside vs outside IR35
A day rate through an umbrella inside IR35 against your own company outside it.
Dividend tax calculator
Tax on dividends stacked on your other income at the April 2026 rates.
Capital gains tax calculator
Tax on a gain at 18% and 24%, stacked on your income.
Bond gain calculator
Tax on an investment bond gain with top-slicing done properly.
Marriage allowance calculator
Whether transferring £1,260 of allowance pays in your household.
Gift Aid calculator
What a donation really costs you, and what the charity and you get back.
Child benefit calculator
What you get, what the £60k–£80k charge claws back, and the fix.
£100k childcare cliff calculator
The £100,000 cliff, what it removes, and the pension contribution that restores it.
Redundancy pay calculator
The £30,000 exemption, tax on the rest, and the pension route.
Student loan calculator
What you repay each year and whether the loan clears or writes off.
Student loan overpayment calculator
Whether overpaying your student loan buys anything at all.

Property and mortgages

13
Buying, borrowing, overpaying, selling and the taxes on each.
Mortgage affordability calculator
How much you could borrow on the tests lenders actually run.
House deposit calculator
How long to save a deposit, and how much sooner with a Lifetime ISA.
Stamp duty calculator
SDLT, LBTT and LTT with first-time buyer relief and the second-home surcharge.
Mortgage repayment calculator
The monthly payment and the full interest bill over the term.
Mortgage overpayment calculator
Interest saved and years cut, against investing the money instead.
Remortgage calculator
Whether a new deal saves money after fees, and the term trap.
Rental income tax calculator
Tax on rental profit stacked on your other income, with the 2027 surcharge.
Rent a room calculator
£7,500 tax-free from a lodger, and the cheaper method above it.
Buy-to-let calculator
From headline yield to the cash a landlord actually keeps after tax.
Rent vs buy calculator
Who is better off after five, ten or twenty years: owner or renter.
Property capital gains tax calculator
Tax on selling a second home or buy-to-let, with private residence relief.
Downsizing calculator
What selling and buying smaller frees, and the income it could provide.
Equity release calculator
How a lifetime mortgage rolls up against the value of the house.

Savings, debt and inflation

12
Your budget and balance sheet, growing money, clearing debt, and what inflation does to both.
Household budget calculator
Your monthly surplus, how far your cash stretches, and where spare money goes next.
Net worth calculator
What you own less what you owe, and how much of it you can actually reach.
Emergency fund calculator
How many months of essentials your cash covers, and the gap.
Savings growth calculator
Regular saving compounded, with tax on the interest, against an ISA.
ISA vs general investment account
The dividend and capital gains tax on investing outside an ISA, and what Bed and ISA saves.
Premium Bonds calculator
Expected tax-free prizes against after-tax savings interest at your band.
Fund charges calculator
What 1% a year costs against 0.2% over a lifetime.
Lifetime ISA calculator
The 25% bonus to 60, and what the withdrawal penalty really takes.
Junior ISA vs junior pension
Saving for a child: theirs at 18, or a 20% top-up locked until 57.
Debt payoff calculator
Avalanche or snowball on your debts: time to clear and interest saved.
Loan repayment calculator
The monthly payment and true cost of a personal or car loan, and what paying extra saves.
Inflation calculator
What a sum buys in 10, 20 or 30 years, and what UK prices really did.

Protection and family

8
The odds of the things insurance is for, and how much cover the gap needs.
Risk reality calculator
The odds of long-term sickness, serious illness or death before retirement.
Income protection calculator
The cover that would hold your essentials, and how long sick pay lasts.
Life insurance calculator
The cover a household needs: debt, income, mortgage, education.
Critical illness cover calculator
The lump sum a serious diagnosis would need to fund.
Maternity and paternity pay calculator
Statutory and enhanced pay week by week, and what the year costs the household.
Tax-Free Childcare calculator
The 20% top-up, who qualifies, and the £100,000 cliff.
Care costs calculator
What care would cost by the time you need it, and who pays.
Care home means test calculator
When the council pays, whether your home counts, and your weekly share.

Inheritance

5
What the estate would pay, and what gifts do to it.
Inheritance tax calculator
What the estate would pay: both bands, the taper and the 2027 pension change.
Who inherits without a will
The intestacy rules: who inherits, and how much, if there is no will.
7-year rule calculator
What a gift really adds to the inheritance tax bill today.
Gifts from surplus income calculator
Regular gifts free of inheritance tax at once, with no seven-year clock.
Inherited pension calculator
What a beneficiary keeps from a pension, as a lump sum or drawdown.

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