Choose where you want to start. Your working figures are kept securely on this device; optional account sync is ready to connect in version 11.
Nothing here locks you into a journey — you can move between tools and come back without resetting your working figures.
Make your mortgage make sense.
Model repayments, interest-rate changes and overpayments.
Your mortgage
Edit any figure
Popular currencies appear first. Tap the search box to type.
£
£
Enter an amount or switch to %
£
£
Base loan amount
£200,000
Loan to value
80%
%
Years50 years
Mortgage type
Regular payments cover interest and gradually repay the loan.
Advanced settings
Optional controls for your mortgage deal, dates, overpayments and fees. Leave them closed unless you need them.
Mortgage deal & future rateOptional
OPTIONAL DEAL DETAILS
Model the end of your current deal.
Your mortgage term is the full repayment period. Use these optional settings only if you want to model a fixed or tracker deal ending earlier and illustrate a different rate afterwards.
years
Mortgage term25 yearsHow long you plan to take to repay the mortgage.
Initial deal period5 years fixed at 5.00%How long this starting rate lasts.
StartYear 5 · DEAL ENDSYear 25
Enter your mortgage figures to estimate the balance when the initial deal ends.
%
Your payment after the initial deal is not known yet. Later years are illustrative until you choose a next rate.
Mortgage datesOptional
Calculated mortgage end date
—
The end date is calculated from the start date and mortgage term. The first repayment defaults to the following month, but you can change it.
OverpaymentsOptional
£
Slide up to£5,000
£
Extra payments reduce principal after the regular payment. Check your lender's limits and early repayment charges.
Fees & financingOptional
£
When you calculate, Finance Lab counts broad mortgage and deposit ranges to help improve the service.
Your inputs remain editable. Results appear only after you press Calculate my mortgage. Save one named mortgage calculation with a free account.
⌁
Ready when you are
Enter your mortgage details, then select Calculate my mortgage to see your repayment, interest, chart and full schedule.
Exact figures stay on your device unless you choose to save a calculation.
Your starting monthly repayment
£1,111.66
Contractual monthly payment before any extra payments
—Starting rate is carried forward for illustration until you model the next deal.
Mortgage-free in
——
Overpayment impact
—Compared with the same mortgage without voluntary overpayments.
Explore your mortgage
Interactive mortgage graphs
Desktop: hover to inspect · touch: tap to enlarge
Balance without overpaymentsBalance with overpaymentsDashed after deal end = illustrative projection
Interest paid during each yearCapital paid down during each yearOn a repayment mortgage, the interest portion usually falls while more of each payment reduces the balance.
Desktop: move across the graph for live values. Touch: tap the chart to open the interactive view.
Where your payments go
Interest share—
● Loan principal—
● Loan interest—
Mortgage payments + upfront fee—
Adjust your mortgage to see the impact.
Overpayment illustrations
Optional repayment scenarios
Customize rate stress test ＋
% points
Enter +0.25 for a quarter-point increase, or -0.25 for a decrease. This models the starting monthly payment at the new rate, not a future rate prediction.
Early repayment illustrations 5% or 10% of the starting monthly payment, on top of your regular payment
The full repayment journey
—
Year
Payment made
Interest paid
Capital paid down
Balance
Capital paid down includes regular principal, voluntary overpayments and any final principal payment. The preview shows the first 5 years or first 12 months. Use Show full schedule to open the complete table.
Final summary
Mortgage illustration
Review your entered figures and the modelled mortgage outcome in one compact illustration.
PERSONAL 8B LABS FINANCE
Choose what you want to compare.
Pick a calculator below. Your current figures remain on this device while you move between tools.
MY MORTGAGE · PRIVATE & CLOUD-READY
My Mortgage.
Your saved mortgage with live balance, repayment and overpayment analysis.
Saved calculations
Sign in to see saved calculations.
Saved mortgages
Add your first mortgage to begin.
Multiple mortgages are a 8B Labs Finance Premium feature.Your first mortgage remains free. Premium unlocks up to 12 saved mortgage profiles.
MY MORTGAGE · LIVE ESTIMATE
My mortgage
ESTIMATED PRINCIPAL OUTSTANDING● Live estimate
—
INTEREST ACCRUED TODAY—
£0.00
of — expected today
Estimated current LTV—
Scheduled payment—Next due: —
Advanced tools & views
REPAYMENT & OVERPAYMENT ANALYSIS
Your mortgage journey
Recorded overpayments are included automatically. Add future overpayments below to see how they could change your balance, interest and finish date.
● Interactive
Applied from the next scheduled payment.
Optional. Set an amount and date.
Must be after today and before the mortgage end.
What if I overpay more from now?Quick illustrations based on your scheduled monthly payment.
Repayment journey
Full mortgage details
Estimated interest this calendar year—
Mortgage ends in—
Deal ends in——
Payment ledger
Record regular payments and overpayments. Payments before the saved balance snapshot remain history only.
Reminders & calendar
Add your mortgage details
Use a lender balance and remaining term from the same date. You can edit these details later.
Data, terms & backup
Mortgage profiles remain on this device for offline use. After signing in, open Account to back up or restore profiles securely through Supabase. Automatic sync activates only after your cloud and device copies match. If they conflict, you choose which version to keep. Cloud storage includes lender names and any addresses you entered. Uninstalling or clearing data can remove the local copy; sign in and back up before doing so. Estimates are not lender statements or financial advice.
DECISION LAB · v10
Compare my options.
Compare two cash-flow-neutral paths: pay cash now and invest the monthly payment you avoid, or finance the purchase and invest the cash you keep.
End-of-term comparison
Live estimate
—
Both paths assume you start with cash equal to the purchase price and have the same monthly cash-flow capacity. The asset being purchased is excluded from the comparison because it is identical in both paths.
Pay cash starts lower because the purchase uses your cash, then invests the monthly finance payment you avoided. Finance starts with the cash retained by borrowing. The purchased asset itself is excluded because it is the same in both paths. Tap to enlarge and inspect the timeline.
Break-even finance rate
—
What changes the answer?
Scenario
Finance rate
Cash return
End difference
Positive means financing leaves more investable cash at the end of the selected term; negative means paying cash and investing the avoided payment leaves more.
Illustrative comparison only. 8B Labs Finance does not model tax rules, investment volatility, early settlement, credit risk, opportunity costs outside this model, or product-specific terms. The result is not financial advice or a recommendation.
06 / PREMIUM PROPERTY PLANNING
Property Investment Lab.
Add properties to build your investment portfolio, then review rent, debt, yield, cash flow and equity across the whole portfolio or open any property for its individual detail.
8B Labs Finance Premium · launches 1 Jan 2027
Property Investment Lab
Unlock rental yield, current LTV, equity, debt-free analysis, annual irregular costs, up to 20 saved property scenarios, comparison views and printable reports.
Premium launches 1 January 2027. Register interest now; no charge is taken in this build.
Your property
Property results
Live estimate
Gross and net rental yield are property-return measures and do not improve merely because the property has no mortgage. Removing debt changes cash flow, interest cost and return-on-equity/cash metrics.
Premium · Test mode
Your portfolio
Add properties to populate your portfolio. Once saved, each property appears here by name; tap a property to open its individual figures and analysis.
Property details
Selected property
Live estimate
Review portfolio
Review the whole portfolio side by side. For the specifics of one property, tap its property card above.
Future Premium updates
Market intelligence roadmap
Regional rent benchmarksLocal average and range data from licensed market-data sources.
Address-based value estimateEstimated property value and rent range using verified property and comparable-market data.
Rent trend trackingRegional changes, market ranges and scenario updates over time.
Short-term rental actualsManual/CSV income, occupancy, cleaning and platform-fee history first; optional booking APIs later.
Desktop & cloud portfolioSecure account sync so the same portfolio can be opened on phone, browser and Windows desktop.
These are roadmap items, not live data in this prototype. A worldwide version will need country-specific data providers rather than one UK-only source.
02 / Borrowing
Borrow with clarity.
Model a personal or business loan, see every repayment, and check how extra payments affect the balance and total interest.
Contractual monthly payment
Live estimate
—
Before voluntary extra repayments
—
—
—
—
Balance over time
Month
Paid
Interest
Principal
Extra
Balance
Planning estimate, not a credit offer or a regulated APR calculation. Uses a fixed nominal annual rate divided by 12, month-end payments and monthly interest. Lenders may use different rounding, daily interest, fees and settlement rules.
03 / Vehicle finance
HP, without the guesswork.
Understand the monthly instalment and what it costs to acquire the vehicle through hire purchase.
Regular monthly instalment
Live estimate
—
Over the full HP agreement term
—
—
—
—
Remaining finance balance
Month
Instalment
Interest
Principal
Balance
Illustration only. Some HP providers calculate charges using flat rates, daily interest, advance payments or fees with different treatment. A nominal borrowing rate is not the same as advertised APR. Ownership is subject to the contract and any final fee.
04 / Vehicle finance
See the whole PCP deal.
Compare monthly payments with the optional final balloon payment and the cost of returning the vehicle. You do not own the vehicle just by making the monthly PCP payments. To buy it, you must pay the agreed final balloon and any applicable purchase fee.
Regular monthly PCP payment
Live estimate
—
Monthly payments alone do not give you ownership. The provider-quoted final balloon and applicable purchase fee must also be paid if you choose to own the vehicle.
—
—
—
—
Balloon and vehicle value
Month
Payment
Interest
Principal
Balance / balloon
Returning the vehicle may incur additional mileage, condition or other contractual charges, which are NOT included in the return figure. A projected resale value is your own assumption, not a guaranteed market value. Check whether the lender quotes a flat rate or APR rather than a nominal rate.
05 / Side-by-side
One vehicle. Three ways to pay.
Use the same vehicle, deposit and part-exchange value to compare a personal loan, hire purchase and PCP. Enter each lender's nominal borrowing rate and term independently.
Compare your entered offers
Live estimate
Keep the example figures below, or copy the rates and terms you have entered in Loan Lab, HP Lab and PCP Lab. Check that the offers refer to the same vehicle price and financed amount before comparing.
The example comparison stays editable; figures are copied only when you request it.
Balance comparison
Outstanding finance over time
Interactive
Personal loanHPPCP
All three lines use the same starting amount financed. PCP can finish with a balloon still outstanding until you choose to buy the vehicle.
All three examples assume monthly interest at the nominal rate ÷ 12, payments at month-end and upfront fees. They may not match lenders' advertised APR or contractual payment methods. The cost-to-own figures include the economic value of any vehicle traded in; the cash-paid figures exclude it. PCP return costs exclude mileage, condition and other end-of-term charges. No result is a recommendation or credit offer.