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·3 min read

Why we built CrestCast

Most of us manage money by looking backwards. We built CrestCast to change that, bringing the same forward-looking tools that businesses rely on to your household.

Most businesses of any size run on three financial statements: a profit and loss account, a balance sheet, and a cashflow forecast. Together they answer three questions every organisation needs to know: are we making money, what are we worth, and can we pay our bills? The answers shape every decision the business makes.

Most households have none of this. At best, a budgeting app that tells you what you spent last month. At worst, a vague sense that the money comes in and the money goes out, with a hope that it's roughly working.

The problem with budgeting apps

Budgeting apps are built around the past. They pull in your transactions, categorise your spending, and tell you whether you were over or under budget last month. That's useful, but it doesn't answer the questions that actually matter when you're making financial decisions.

What will our net worth be in 10 years? When does the mortgage clear? If we had another child, what would that do to our finances? If one of us took a career break, how long could we manage? These questions need a forecast, not a transaction history.

One person carrying all the knowledge

There's another problem we kept seeing: in most couples, one person carries all the financial knowledge. They know the mortgage rate, the pension contributions, when the fixed rate ends, what the joint account actually covers. The other partner has a rough idea but not the full picture.

That's not a good place to be making decisions from, and it creates a real vulnerability if circumstances change. Both partners deserve to understand their financial future.

What CrestCast is

CrestCast gives your household a proper financial model. Enter your income, your bills, your assets and debts, and the app builds a forward-looking picture of your P&L, your net worth trajectory, and your day-by-day cashflow. Both partners can see the same picture, model decisions before making them, and track progress over time.

CrestCast Input home screen in the Combined view, as at 14/08/2026: a cash balance of £10,800, then a tile per statement. Monthly surplus +£2.4k a month, tagged 59% surplus margin and 6% savings rate, with cash in £4.4k against cash out £1.8k. Monthly profit +£3.2k a month, tagged 72% wealth rate, with income £4.4k against expenses £1.2k. Below them a net worth tile reading £125.4k
The three questions a business always knows the answer to, stacked on one screen for a household. Can we pay our bills: £2.4k a month of surplus, with the cash in and cash out behind it printed on the same tile. Are we making money: £3.2k of profit, a 72% wealth rate, which is profit as a share of income. What are we worth: £125.4k. Note that the first two disagree, £2.4k of cash surplus against £3.2k of profit, which is exactly why a household needs both rather than either one. Each tile opens into the full statement behind it.

It's built entirely for UK finances: income tax, National Insurance, student loan plans and pension contributions, all calculated correctly so the numbers you see are the numbers you'll actually live with.

We built it because we wanted it ourselves. We think you will too. Open CrestCast and build your household's first forecast in a few minutes.

About this post

There's no modelled scenario here. This is a company/about post, so the one screenshot above is simply the app's own Input home screen for the demo household, before any single statement is opened, illustrating the three-statement idea the post describes rather than a specific decision being modelled. All three tiles are computed from the same set of inputs, which is why the cash surplus and the profit differ without either being wrong.

For a worked example of the app actually being used to compare a decision, see "Comparing Financial Scenarios Before You Decide" or any of the "Should I..." posts on this blog.

Build your household's first forecast

Income, bills, debts and savings in once; your cashflow, profit and loss and net worth ten years out. It takes a few minutes to see your first full picture.

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