Stop guessing,
start planning.
See where everything your household earns, owes and owns is heading, spot risks and opportunities early, and test a decision before you make it.
30 days free, no card. Then £7.99 a month or £79.99 a year for the whole household.Your data: where it lives →
Get the app- Net worth, 2036
- £617.7k
- Surplus a month
- +£230
- Lowest cash, April 2027
- £9.8k
Sample household, invented figures, in today's money, as at 09/10/2026. Surplus is the next 12 months' average.
CrestCast builds a day-by-day model of your household from what you enter, ten years ahead, and shows it as cash, profit and loss and net worth, in today's money or future pounds.
Questions it answers
Each opens the sample household's forecast, where you can ask it.
- When will we be debt free?Open the demo →
- What will we be worth in 5 years?Open the demo →
- How much interest will we pay on the mortgage over 5 years?Open the demo →
- What will my child’s savings be worth at 18?On the sample household, Olivia’s pot reaches £17,296 by 18 and Noah’s £19,181.Open the demo →
- Could we afford a £20k kitchen?Open the demo →
- When is our cash lowest?£9.8k on 27/04/2027, on the sample household.Open the demo →
Sample household, invented figures, in today's money, as at 09/10/2026.
What you'll see in the demo
Where your money is heading
Net worth ten years out, the month each debt clears, what a child's savings reach by 18, and the effect of a decision on all of it. Overpaying the mortgage £300 a month, on the sample household, leaves net worth £7.8k lower in 2036, in today's money: the ISA that cash would have fed is assumed to grow faster than the mortgage costs.
No account needed. It opens on the £300 mortgage overpayment.
- No bank login.
- CSV read on your device.
- You choose what goes in.
Your financial data is never sold
Never sold or used for advertising, and shared only with the processors named in the privacy policy.
Privacy policy →The method is published
How every figure is worked out, and the assumptions behind it.
How the forecast works →The engine handles mortgages, pensions, student loans, UK tax, children, investments and debt.
What the demo shows
The forecast
Cash, P&L, debts and net worth, ten years out, side by side with your plan.
See a cash shortfall before it arrives
The month cash first dips below zero, with the bills and debts behind it.
Test a decision
Go part-time, move house, overpay the mortgage. Each is saved as a version beside your plan.
The workings
Ask about any figure on any tab. CrestCast does the maths, not the AI, and every figure comes from something you entered.
Built-in AI assistant. Optional, off until you switch it on. What it can and cannot do →
£7.99 a monthor£79.99 a year
Annual saves £15.89 a year, about two months free.
One subscription covers your whole household Run by you
Start free trial30 days free, no card. Then £7.99 a month or £79.99 a year for the whole household.
What's included →Common questions
Is my data safe?
Yes. Your financial data is locked to your account by row level security, so nobody outside your household can reach it, and inside your household your partner sees only what you chose to share. It is stored on Supabase, an independently audited and certified cloud platform (SOC 2 Type 2 and ISO 27001), and encrypted both while it moves and while it is stored. CrestCast never sees your password or your card details. Read more →
Do you sell my data?
No. Your data is used only to run your own forecast. It is never sold, never used for advertising, and shared only with the processors named in our privacy policy.
Can CrestCast access my bank account?
No. CrestCast never connects to your bank and never asks for your bank login. You enter your own numbers, your data stays private, and the forecast reflects exactly what you tell it. If you would rather not type everything in, hand it the CSV your bank already exports. If the layout is not recognised, you map the columns once. CrestCast picks out the payments that repeat and offers each one as a bill or an income source for you to keep or ignore. That happens on your own device, with nothing uploaded. Read more →
Does the AI make decisions for me?
No. The assistant is optional. It drafts inputs from what you tell it and answers questions using only figures your forecast already shows. Nothing goes into your plan until you add it, and anything it drafts, such as a what-if, is saved as a separate version beside your plan, so the choice stays yours.
Is this financial advice?
No. CrestCast is a forecasting and planning tool, not regulated financial advice. It shows what each choice does to your numbers; the decision is yours.
Where is my data stored?
Your plan is stored by Supabase in Frankfurt, Germany (EU). The app is served by Vercel, which does not store your plan, and payments go through Stripe, which keeps your card details. If you use the AI assistant, your message goes to Anthropic, which can process it in the United States and does not train its models on it.
Can I delete everything?
Yes. Delete Account in Settings removes your figures, forecasts and saved versions. Nothing goes straight away: we wait 30 days, and signing back in before then cancels it. If you share a household, your partner keeps their own copy of the joint items.
How accurate is the forecast?
The arithmetic is not estimated. UK income tax, National Insurance and student loan repayments are calculated from the published rules, every loan runs on its own repayment schedule, and your bills and pay changes land on the dates you give them. When a salary or a bill turns out different, log the real amount in your inputs and the forecast carries on from it. Tap any figure on a statement to see how it was worked out. Read more →
More
Questions it answers
- A big payment falls due on a date we already know. Will the cash be there?
- If one of us stopped working, how long could we manage?
- What will our net worth be in five years, and in ten?
- When does each debt clear, the student loan included, and what does that free up?
- When does every debt clear, and what would overpaying bring forward?
- Does paying the debt down actually leave us better off?
Show all 13 questionsShow fewer questions
- At what point do we own more than we owe?
- What does a pay rise actually change over the next decade?
- Could we afford the bigger house and still be where we want to be in ten years?
- Can one of us go part-time, or take leave, when the baby comes?
- Should we overpay the mortgage, or invest the money instead?
- If we had another child, what would that do to our finances?
- Pension or ISA, with whatever is left over?
The forecast
- Cashflow forecast
- Profit & loss forecast
- Net worth forecast
- Three-way modelling, explained
- The month every debt clears
- Changes you already know are coming
- Where spare cash goes
- Why your forecast shouldn't go overdrawn
- Compare two versions of your plan
- Comparing scenarios before you decide
- Why ten years, not thirty
Getting started
- A working forecast in under an hour, set up by chatting. Prefer forms? Fill them in yourself.
- Planning as a couple. A partner you invite starts with viewing access.
- Managing joint finances
- Planning as a family
- Should I open a Junior ISA?
- For financial advisers
- Do you need a financial adviser?
How it compares
Stop guessing,
start planning.
Start your trial, invite your partner, and see where your household's money is heading.
Start free trial30 days free, no card. Then £7.99 a month or £79.99 a year for the whole household. Cancel any time to stop the next renewal.
Luke Walsh BSc ACA PgDip
Founder, CrestCast
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