The long view on household money

Know the cost of your next move.

LongLens sits between your budgeting app and a retirement calculator. See your real monthly margin, spot your mortgage cliff months ahead, and fork your life into what-if branches before you commit to anything.

Open the app See how it works

No account. No bank link. Every number stays in your browser.

01 · Financial cockpit

Your real margin.
Not a guess.

Income minus survival costs, minimum debt payments and housing overheads. What is left is the money you can truly spend or invest.

Freeflow monthly margin £0
£6,840net income − £1,928housing and debt − £1,465essential living
Liquid runway
0months

£31,200 of accessible cash against a £3,393 monthly burn. Retirement pots are left out on purpose.

Cash flow waterfall
Housing and debt service£1,928
Essential living£1,465
Discretionary lifestyle£1,120
Unallocated, building wealth£2,327
Any currency, any cadence

Pick your own denomination, income rhythm and savings vehicles. Nothing is locked to one country.

03 · Scenario branches

Fork your life.
Keep your numbers.

Branch your baseline like code. Explore upsizing, downsizing or staying put in parallel, and your real figures are never overwritten.

Projected net worth, illustrative household
  • Stay Put & Max Out PensionsBaseline · freeflow £3,447
    £812k
  • Upsize to 4-Bed SuburbBranch · freeflow £1,964
    £654k
  • Downsize to the CoastBranch · freeflow £4,041
    £840k

04 · Move builder

The costs everyone forgets.

Set a sale price and a target price. LongLens works out the equity you roll forward, the new debt you need, and every pound of friction in between.

Sale proceeds£425,000
  • Mortgage redeemed£286,400
  • Friction£36,570
  • Deposit rolled forward£102,030
Friction-cost engine
  • Transfer taxStamp Duty on £610,000£20,500
  • Agent disposal fee1.2% of sale price plus VAT£6,120
  • Legal, title and surveyConveyancing and structural survey£3,450
  • Moving and furnishingRemovals plus a furnishing allowance£6,500
Total friction6.0% of the purchase price£0

05 · Stress test

Break it here.
Not in real life.

Drag the sliders. This is the same deterministic maths the app runs, applied to the upsize branch.

Margin holds £1,964 freeflow a month under these conditions
Payment£2,662
LTV83.3%
Runway6.4 mo

Above the 80% band · reserves untouched

0 bps
−200 bps+500 bps
0%
−20%+30%
0%
0%+25%
0%
0%−60%

07 · Onboarding

Four steps.
Under three minutes.

0:00
  1. 1Currency and incomeYour base denomination and what lands each month.
  2. 2Fixed outgoingsThe baseline you cannot skip.
  3. 3Housing profileRent, or own with your loan details.
  4. 4Reserves and assetsAccessible cash and everything that is not your home.

08 · Data sovereignty

Zero servers.
Zero lock-in.

Every figure is calculated in your browser from numbers you typed. Export the lot as JSON or CSV whenever you like, and take it anywhere.

No accountNo bank linkJSON exportCSV export

09 · Pricing

Free to see.
Pro to decide.

The cockpit is free for good. Pro is for the months when you are weighing a real move.

Free £0

The cockpit: your real margin, runway and cash flow waterfall. A countdown to your rate cliff, a 5-year baseline projection, and full export.

Pro · monthly £5

The full debt cliff radar, unlimited scenario branches with the move builder, stress tests, side-by-side compare, the readiness score, and 10 and 25-year projections. Cancel any time.

Pro · annual £36

Everything in Pro for a year. Works out at £3 a month.