# Hundred Summers

> Hundred Summers (hundredsummers.co.uk) is a UK personal financial-planning web app. Users enter their own figures — income, pensions, property, savings, expenses, life events — and Hundred Summers projects every year of their financial life: cashflow, tax, net worth, retirement readiness, inheritance, and how the plan survives simulated market stress. It is an educational tool, not regulated financial advice: it never recommends products, and every number traces to published assumptions. Plan data stays on the user's own device — the app makes no third-party network requests with financial data.

Key facts:

- Audience: UK individuals and households planning their own finances, plus financial advisers whose clients share plans with them.
- Coverage: UK income tax (rest-of-UK and Scottish bands), National Insurance, capital gains tax, pension rules (annual allowance and taper, carry-forward, MPAA, PCLS, drawdown, annuities, State Pension), inheritance tax (nil-rate bands, taper, gifts and PETs), property and mortgages, care costs and longevity, and protection policies.
- Stress testing: 500-path Monte Carlo simulation with correlated equity/bond/property returns, fat-tailed shocks and persistent inflation, validated against 1928–2023 market history.
- Privacy: financial data is stored only on the user's device. Backup files are encrypted by default (user-switchable); adviser sharing is always end-to-end encrypted — the server holds ciphertext it cannot read.
- Pricing: Free tier (data entry, overview, cashflow, savings, expenses, property). Premium at £4.99/month (scenarios, stress testing, tax, pension income, inheritance, couples planning, risk profiling, reports, AI Copilot). Adviser tier: free two-month launch access, then £39/month per adviser by arrangement — sign-up via official work email, verified before the portal is enabled.
- Hundred Summers is education, not advice. For personal recommendations users are directed to an FCA-regulated financial adviser; free impartial guidance is available from MoneyHelper (moneyhelper.org.uk).

## Docs

- [Pricing](https://hundredsummers.co.uk/pricing.html): Free tier; Premium £4.99/month; Adviser free two-month launch access then £39/month.
- [Free calculators](https://hundredsummers.co.uk/tools.html)
- [Methodology & assumptions](https://hundredsummers.co.uk/methodology.html): every assumption behind the projections, published in full — UK tax and pension rules, growth and inflation defaults, the Monte Carlo market model, the historical backtest, limitations and sources.
- [Pension drawdown calculator](https://hundredsummers.co.uk/pension-drawdown-calculator.html): free, in-browser — how long a pot lasts and the sustainable spending level, computed on a full year-by-year projection with UK income tax and the State Pension.
- [Inheritance tax calculator](https://hundredsummers.co.uk/inheritance-tax-calculator.html): free, in-browser — NRB, RNRB with the £2m taper, transferred spouse bands, the 36% charity rate, and the 2027 pensions-in-estate rule.
- [Salary sacrifice calculator](https://hundredsummers.co.uk/salary-sacrifice-calculator.html): free, in-browser — income tax and NI saved on actual bands, including the £100k-£125,140 60% relief zone and the employer NI pass-on.
- [ISA vs pension calculator](https://hundredsummers.co.uk/isa-vs-pension-calculator.html): free, in-browser — the same gross pay via salary sacrifice or into an ISA after tax, compared with the 25% tax-free lump sum and your retirement rate.
- [Annuity calculator](https://hundredsummers.co.uk/annuity-calculator.html): free, in-browser — guaranteed lifetime income at indicative market-average rates, with spouse provision, guarantees, index-linking and enhanced rates priced in.
- [State Pension deferral calculator](https://hundredsummers.co.uk/state-pension-deferral-calculator.html): free, in-browser — the statutory ~5.8%/yr uplift, the income forgone, and the honest breakeven age.
- [FIRE calculator](https://hundredsummers.co.uk/fire-calculator.html): free, in-browser — Lean/Regular/Fat FI numbers and ages plus Coast FI, on the same definitions as the app's FIRE card.
- [Voluntary NI calculator](https://hundredsummers.co.uk/voluntary-ni-calculator.html): free, in-browser — the after-tax breakeven on buying missing State Pension years (1/35th of the full pension each, for life).
- [7-year rule calculator](https://hundredsummers.co.uk/seven-year-rule-calculator.html): free, in-browser — what a gift adds to the IHT bill today, with the nil-rate-band ordering and statutory taper relief done properly.
- [Mortgage overpayment calculator](https://hundredsummers.co.uk/mortgage-overpayment-calculator.html): free, in-browser — interest saved and years cut, honestly compared against investing the same money.
- [How much to retire calculator](https://hundredsummers.co.uk/how-much-to-retire-calculator.html): free, in-browser — the pot solved by a full year-by-year projection with tax and the State Pension, not the 25x rule.
- [Capital gains tax calculator](https://hundredsummers.co.uk/capital-gains-tax-calculator.html): free, in-browser — the £3,000 exemption then 18%/24% by remaining basic-rate band, gains stacked on income.
- [Pension carry-forward calculator](https://hundredsummers.co.uk/pension-carry-forward-calculator.html): free, in-browser — this year's tapered allowance plus three prior years' unused allowances, each tapered on its own income.
- [Take-home pay calculator](https://hundredsummers.co.uk/take-home-pay-calculator.html): free, in-browser — income tax (rUK or Scottish), NI and student loan on your actual salary — plus your true marginal rate, including the hidden 60% zone.
- [Bonus tax calculator](https://hundredsummers.co.uk/bonus-tax-calculator.html): free, in-browser — no special bonus rate exists — a bonus is income stacked on top of your salary. See what you actually keep, and what sacrificing it would do.
- [Dividend tax calculator](https://hundredsummers.co.uk/dividend-tax-calculator.html): free, in-browser — the £500 allowance, then the April-2026 10.75%/35.75%/39.35% rates with dividends stacked as the top slice of your income.
- [Child benefit calculator](https://hundredsummers.co.uk/child-benefit-calculator.html): free, in-browser — what you claim, what the £60k–£80k High Income Charge claws back, and the pension contribution that would restore the lot.
- [Student loan calculator](https://hundredsummers.co.uk/student-loan-calculator.html): free, in-browser — 9% above your plan's threshold, through payroll, until it clears or writes off — a tax in all but name, priced on the real plan table.
- [Pension projection calculator](https://hundredsummers.co.uk/pension-projection-calculator.html): free, in-browser — your pot at retirement net of charges — with the today's-money figure and what your fees cost against a zero-fee world.
- [Remortgage calculator](https://hundredsummers.co.uk/remortgage-calculator.html): free, in-browser — both deals amortised in full: monthly change, interest saved net of fees, fee payback — and the term trap flagged when it bites.
- [Equity release calculator](https://hundredsummers.co.uk/equity-release-calculator.html): free, in-browser — the compound roll-up of a lifetime mortgage against your home's value — how much of the house is left, which providers' calculators don't lead with.
- [Life insurance calculator](https://hundredsummers.co.uk/life-insurance-calculator.html): free, in-browser — the DIME method with every part visible — Debt + Income + Mortgage + Education, net of cover you already hold.
- [Life expectancy calculator](https://hundredsummers.co.uk/life-expectancy-calculator.html): free, in-browser — oNS cohort baselines with honest, clamped adjustments — and the plan-to age with the buffer planners add.
- [When can I retire calculator](https://hundredsummers.co.uk/when-can-i-retire-calculator.html): free, in-browser — the earliest fundable retirement age, found by testing each candidate age with a full year-by-year projection including tax and the State Pension.
- [Self-employed tax calculator](https://hundredsummers.co.uk/self-employed-tax-calculator.html): free, in-browser — income tax on profits plus Class 4 NI at 6%/2%, with the Class 2 abolition explained.
- [Rental income tax calculator](https://hundredsummers.co.uk/rental-income-tax-calculator.html): free, in-browser — rental profit stacked on other income at real bands, including the April-2027 +2pp property surcharge.
- [Marriage allowance calculator](https://hundredsummers.co.uk/marriage-allowance-calculator.html): free, in-browser — the £252 credit with both sides of the transfer priced and four-year backdating explained.
- [Tax-free lump sum calculator](https://hundredsummers.co.uk/tax-free-lump-sum-calculator.html): free, in-browser — the 25% maximum under the £268,275 Lump Sum Allowance, and PCLS-up-front vs UFPLS compared.
- [Bond gain calculator](https://hundredsummers.co.uk/bond-gain-calculator.html): free, in-browser — chargeable event gains with HMRC top-slicing and the 20% onshore credit, onshore vs offshore.
- [Lifetime ISA calculator](https://hundredsummers.co.uk/lifetime-isa-calculator.html): free, in-browser — the 25% bonus projected to age 60, with the early-withdrawal charge priced honestly (6.25% of your own money).
- [Mortgage repayment calculator](https://hundredsummers.co.uk/mortgage-repayment-calculator.html): free, in-browser — the true monthly payment and full interest bill, amortised month by month, with the interest-only comparison.
- [Redundancy pay calculator](https://hundredsummers.co.uk/redundancy-pay-calculator.html): free, in-browser — the £30,000 exemption, the excess at real bands (60% trap included), and the pension-sacrifice saving.
- [Care costs calculator](https://hundredsummers.co.uk/care-costs-calculator.html): free, in-browser — in-home, residential and nursing care compounded at care inflation, with the England means test explained.
- [Downsizing calculator](https://hundredsummers.co.uk/downsizing-calculator.html): free, in-browser — capital freed after moving costs (tax-free under private residence relief) and the income it could buy.
- [£100k childcare cliff calculator](https://hundredsummers.co.uk/childcare-cliff-calculator.html): free, in-browser — the 60% tax zone plus the childcare-support cliff at £100,001, and the pension contribution that restores both.
- [Student loan overpayment calculator](https://hundredsummers.co.uk/student-loan-overpay-calculator.html): free, in-browser — overpay vs invest, simulated to write-off with real plan rules and your statement's interest rate.
- [Safe withdrawal rate calculator](https://hundredsummers.co.uk/safe-withdrawal-rate-calculator.html): free, in-browser — your personal SWR solved by a full projection with UK tax and the State Pension, compared against 4% and 3.5%.
- [ISA bridge calculator](https://hundredsummers.co.uk/isa-bridge-calculator.html): free, in-browser — early retirement before pension access, tested by the real projection with pensions locked until 55.
- [Debt payoff calculator](https://hundredsummers.co.uk/debt-payoff-calculator.html): free, in-browser — avalanche vs snowball simulated month by month, with the interest difference priced.
- [Would your retirement have survived 1929?](https://hundredsummers.co.uk/survived-1929.html): free, in-browser interactive — your plan replayed through every complete market window since 1928 (the 1929 crash, the 1966–81 inflation grind, the 2000s lost decade), each a full UK simulation with tax and the State Pension.
- [Guide: The 4% rule — what it misses for UK retirees](https://hundredsummers.co.uk/guides/four-percent-rule-uk.html)
- [Guide: The pension annual allowance taper, explained](https://hundredsummers.co.uk/guides/pension-annual-allowance-taper.html)
- [Guide: The 60% tax trap between £100,000 and £125,140](https://hundredsummers.co.uk/guides/sixty-percent-tax-trap.html)
- [Guide: UFPLS, drawdown or annuity — the three ways to take pension income](https://hundredsummers.co.uk/guides/ufpls-vs-drawdown.html)
- [Guide: Deferring your State Pension — the honest breakeven](https://hundredsummers.co.uk/guides/state-pension-deferral.html)
- [Guide: FIRE in the UK — what the American playbook misses](https://hundredsummers.co.uk/guides/fire-uk.html)
- [Guide: Buying National Insurance years — the best deal in UK finance](https://hundredsummers.co.uk/guides/buying-ni-years.html)
- [Guide: The 7-year rule for gifts — and why taper relief disappoints](https://hundredsummers.co.uk/guides/seven-year-rule.html)
- [Guide: Overpay the mortgage or invest? The honest arithmetic](https://hundredsummers.co.uk/guides/mortgage-overpay-vs-invest.html)
- [Guide: How much do I need to retire in the UK? Solved, not guessed](https://hundredsummers.co.uk/guides/how-much-to-retire-uk.html)
- [Guide: Sequence-of-returns risk, shown with real market history](https://hundredsummers.co.uk/guides/sequence-of-returns-risk.html)
- [Guide: Care home fees — the numbers nobody explains until it's urgent](https://hundredsummers.co.uk/guides/care-home-fees.html)
- [Guide: Pensions and inheritance tax from April 2027](https://hundredsummers.co.uk/guides/pensions-iht-2027.html)
- [Guide: Which account to spend first in retirement](https://hundredsummers.co.uk/guides/retirement-drawdown-order.html)
- [Guide: Drawing retirement income as a couple — the coordination dividend](https://hundredsummers.co.uk/guides/couples-drawdown-coordination.html)
- [Guide: The MPAA — the £10,000 trap that outlasts the decision that sprang it](https://hundredsummers.co.uk/guides/mpaa-trap.html)
- [Guide: Redundancy — the tax playbook](https://hundredsummers.co.uk/guides/redundancy-tax.html)
- [Guide: The £100k childcare cliff — the worst-designed threshold in UK finance](https://hundredsummers.co.uk/guides/childcare-100k-cliff.html)
- [Guide: Inheriting money — the order of operations](https://hundredsummers.co.uk/guides/inheritance-windfall.html)
- [Guide: What a defined benefit pension is actually worth](https://hundredsummers.co.uk/guides/db-pension-value.html)
- [App guide](https://hundredsummers.co.uk/help/): tab-by-tab walkthrough of the app with narrated videos.
- [How Hundred Summers compares](https://hundredsummers.co.uk/compare.html): dated, factual comparison against the UK consumer, adviser and international field: Guiide, RetireEasy, EvolveMyRetirement, Moola, Voyant, CashCalc, EV Pro and ProjectionLab.
- [What's new](https://hundredsummers.co.uk/whats-new.html): the product changelog.
- [Full product and methodology summary](https://hundredsummers.co.uk/llms-full.txt): tiers, feature list, calculation engine assumptions, privacy architecture, and the adviser portal.

## Contact

- Email: contact@hundredsummers.co.uk (Hundred Summers, Bristol, UK)