Live · 2026

Can I Afford It?

One number: what you can spend today.

A web app that works out roughly how much you can spend each day until payday, after your bills and a buffer you choose.

Try it live

Launch video, 1 min 6 s

01The problem

The balance wasn't the problem. Knowing what I could spend was.

Having £1,000 in your bank account doesn't mean you have £1,000 to spend. Before buying anything I'd check my balance, think about the bills still to come, count the days to payday and do the maths in my head. I'd still be unsure.

So I built something that does that sum and gives me one number.

In the account

£1,000.00

To spend today

£27.77

£1,000 balance, less £450 of bills due before payday and a £50 buffer, leaves £500. Over 18 days that is £27.77 a day. Illustrative figures, the same demonstration data as the screenshots.

02The product in action

Every screen answers one question.

Captured from the live app. The balance, bills and spending shown are demonstration data, not anyone's real finances.

What can I spend today?

The answer comes first.

Home opens on the daily figure. The working sits under it: what is left to spend until payday, the bills still to come and the buffer you asked it to keep back.

Home screen on a phone. Estimated daily allowance of £27.77 a day until payday on Friday 30 October, then £500 to spend until payday, £450 of unpaid bills and a £50 emergency buffer, from a tracked balance of £1,000.

What is still to come out?

Bills are held back first.

Every bill due before payday is held back from the daily figure. Bills due after payday are listed too, and marked as not counted yet.

Bills screen. £450 is set aside for unpaid bills before payday: Energy £120, Council tax £145, Phone £35 and Car insurance £150. A Later group lists bills due after payday, not counted yet.

Can I buy this?

Ask before you buy.

Type a price and it answers in plain words: yes, yes but it is a stretch, or probably not. It is a what-if. Nothing is saved unless you say you bought it.

Purchase check for £12. The answer is: Yes, looks fine. It fits in today's allowance of £27.77. — £12: Yes, looks fineThe same balance, three prices. Pick one.

Purchase check for £90. The answer is: Yes, but it is a stretch. The daily allowance would drop to about £22.77 until payday. — £12: Yes, looks fineThe same balance, three prices. Pick one.

Does it only work on a phone?

It fits the screen you have.

One column on a phone. A wider column on a tablet. On a laptop, a sidebar, with the price check and a calendar of bills beside the number.

Home on a laptop: a sidebar on the left, the daily allowance in the middle, the price check on the right and a calendar of bills due before payday underneath. — Laptop1440 px wide

Home on a tablet: one wide column with the daily allowance, recent activity and the next bills, and a tab bar along the bottom. — Tablet820 px wide

Home on a phone: one column with the daily allowance first and a tab bar along the bottom. — Phone390 px wide

03Why I made these decisions

The decisions, and what each one cost.

I only wanted one number.

Budgeting apps show me everything. All I wanted to know was whether I could buy the thing.

Trade-off

No charts, categories or monthly reports.

The allowance card: £27.77 a day for the next 18 days, with £500 to spend until payday, £450 of unpaid bills and a £50 emergency buffer listed under it. — The card at the top of Home.

It doesn't connect to your bank.

You type your balance in yourself, so anyone can try it in a minute without handing over access to their account.

Trade-off

It only knows what you tell it. If you forget to record something, the number is off.

First screen of the app, headed Know what you can spend today. It lists what you will need: your bank balance, your next payday and your regular bills. A line reads: No bank login. What you enter stays on this device. — The first screen, in the app's light theme.

It says no.

Type in a price you can't cover and it tells you "probably not". An answer you can trust has to be able to disappoint you.

Trade-off

It will sometimes be the thing telling you not to buy something.

Purchase check for £650. In red: Probably not. It would leave you £150 short of your unpaid bills and buffer before payday. — The purchase check, asked about £650.

A bill stays unpaid until you mark it paid.

The app never guesses, because one wrong guess throws the whole number off.

Trade-off

A little more tapping.

Bills screen with a prompt: Mark Energy as paid? It asks whether the £120 left the account after the balance was last entered, with the choices Yes, take £120 off my balance and No, my balance already includes it. — Marking a bill paid asks one question, so the money only comes off once. The balance and the bills total both drop by £120 and the daily allowance stays at £27.77.

Home screen after the bill is marked paid. The allowance is still £27.77 a day. Unpaid bills now show 3 bills and £330, from a tracked balance of £880. A message reads: Energy paid. £120 taken off your balance. — Marking a bill paid asks one question, so the money only comes off once. The balance and the bills total both drop by £120 and the daily allowance stays at £27.77.

It works without an account.

You can use it on one device with nothing stored anywhere else. Sign in only if you want the same numbers on your phone and laptop.

Trade-off

Without an account, clearing your browser data loses it.

The Account part of Settings. It reads: You are using the app on this device only. Create an account to see the same balance, bills and spending on your other devices. Below it is a button to sign in or create an account. — Part of the Settings screen.

04How I built it

From a personal frustration to a working product.

I designed it and built it with Claude Code, frontend and backend. I directed the product: what it should do, what to leave out, how it should feel, and what was wrong when something didn't work. Claude Code wrote the code.

Role: Designed and built, solo
Built with: React, TypeScript, Tailwind CSS, Supabase, Vercel

05Where it stands and what’s next

Where it stands

Live and free to use in any browser
Can be added to a phone's home screen and works offline
Optional accounts keep your data in step across devices
Each account can only read its own data, checked with database tests
Still a work in progress

What’s next

1Real profile of how people use it, once there are users
2A cleaner web address

06Try it yourself

Put your own numbers in.

It is free, it runs in the browser and you don't need an account to start.

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