Someone asks me this roughly once a month. Usually a friend of a friend who has found a nice little unit, done a rough sum on a napkin, and wants to know if their savings will cover it.

The honest answer for a modest café outside London: somewhere between £40,000 and £100,000, and most first-timers land in the £50,000 to £80,000 range once everything is actually paid for. That is a wide bracket on purpose. The single biggest variable is the state of the unit you take on, and I will come back to that more than once.

I have fitted out three sites over 17 years - two cafés and a bakery. Here is where the money really goes, line by line, so you can build a number that survives contact with reality rather than a napkin.

Premises: what you pay before you have made a single coffee

Most commercial landlords want a deposit of three to six months' rent, plus the first month up front. For a small unit outside London that might be £3,000 to £6,000 before you have so much as touched the keys. In a prime town-centre spot it can be £15,000 to £30,000 or more.

On top of that sit the legal and agent fees on the lease. A few hundred to a couple of thousand pounds, depending on how complicated the lease is and whether you get a solicitor to read the repairing clauses properly. You should. A full repairing and insuring lease can quietly hand you the cost of a new roof three years in.

Then the question that swings the whole budget: what condition is the shell in? An ex-café with extraction, drainage and a three-phase electrical supply already in place is a completely different number to a bare retail unit that has only ever sold greeting cards. That one factor moves your total by tens of thousands. Buying a café that is already trading takes that logic to its conclusion, since you inherit the fit-out, the kit and the customers in one go, though the seller's accounts hide their own set of costs.

Fit-out: the bit first-timers always underestimate

Refreshing an existing café - fresh paint, some furniture, a deep clean, new signage - can be done for a few thousand pounds if you are sensible. A full refit of a bare unit, with a proper commercial kitchen built from nothing, is a different order of magnitude and can run well into the tens of thousands on its own.

The three things that catch everyone are extraction, plumbing and electrics. They are invisible, they are not glamorous, and they are where the money disappears. Nobody photographs their new grease-trap for the launch post, but you cannot open without one.

In my experience it is always the extraction and the electrical supply that overrun. Every single time. Get a proper written quote for both before you sign anything, not a builder's cheerful guess over a cup of tea. If the unit needs a three-phase supply upgrading, you want to know that number while you can still walk away.

Equipment: the shiny bit that is easy to overspend on

Your core list is short but expensive: an espresso machine and grinder, refrigeration, an oven, a dishwasher, and an EPOS till. A modest set-up starts around £3,000. A high-end fit can run to £30,000 or £40,000 once you are into a two-group machine, under-counter fridges, a serious grinder and proper prep kit. Whichever end of that range you land on, the purchase price is only the start, because servicing and the days a dead espresso machine costs you keep landing long after the kit is paid for.

You do not have to buy all of it outright on day one. Whether you lease, finance, or buy second-hand changes your opening cash position enormously, and the right answer depends on your numbers, not on what looks best behind the counter. I have laid out the trade-offs of leasing versus buying your café equipment if you are weighing that decision, because getting it wrong ties up cash you will badly need in month two.

The costs nobody warns you about

This is where budgets quietly leak, because none of these lines are exciting enough to remember.

Food business registration. It is free, and you must register with your local authority at least 28 days before you start trading. It cannot be refused, so there is no reason to leave it late.
Planning. A shop-to-café change is usually within the same Use Class E, so a change of use often needs no planning permission at all. But new building works, an external extraction flue, or outdoor seating can still require consent. Check with your council before you commit money.
Insurance. Public liability, employers' liability, buildings and contents, product cover. Anywhere from a few hundred to over a thousand pounds a year depending on your cover and site.
The music licence. If you play any music at all, radio and Spotify included, you need TheMusicLicence from PPL PRS. It is typically a few hundred pounds a year and scales with the size of your space. It is genuinely the cost nobody warns you about, which is why I wrote up exactly what you pay for a café music licence after it caught me out.
Waste. A commercial waste contract is a legal requirement. You cannot put trade waste in the household bins, and the council will happily fine you for trying.
A card machine and merchant account, plus whatever your EPOS software costs you each month.

Licences and permits together tend to land somewhere in the £400 to £800 range as a one-off. But it is the ongoing ones - insurance, music, waste, card fees - that people leave out of the first-year plan and then meet as an unpleasant surprise.

Opening stock and smallwares

The stock itself is the easy part to picture: coffee, milk, your opening larder, the cakes for day one. Call it a few hundred to a couple of thousand pounds depending on your menu.

The part that surprises people is smallwares. Cups, saucers, plates, cutlery, glassware, jugs, tampers, tins, chopping boards, cleaning kit. None of it costs much on its own and all of it together comes to more than you think - realistically £1,500 to £4,000 for a small café. Write the list before you order, because the drip-drip of "oh, we also need" is how people blow through their contingency before they have even opened.

Working capital: the line that saves you

Here is the line I wish someone had underlined for me the first time. You need three to six months of running costs sitting in reserve, on top of everything above. Rent, wages, utilities, stock, the lot.

Almost no café is busy from day one. You will have a soft opening, a slow few weeks, a wobble in the first winter. Working capital is what carries you through that gap between opening the doors and the tills reliably covering the bills.

The single most useful thing you can do before you sign a lease is a reality check on the trade itself. Work out your break-even point in covers per day at the rent you are being offered. If the number of customers you need every day to break even makes you wince, that is the deal telling you something before it costs you your savings.

Contingency: the 10 to 15% you will be glad of

Whatever total you have arrived at, add 10 to 15% on top and do not touch it unless you have to. Something always overruns. A wall opens up to reveal old wiring. The extraction quote comes back higher. A piece of second-hand kit dies in week one.

I have never once done a fit-out that came in exactly on budget, and I have done three. The contingency is not pessimism, it is planning. The people who skip it are the ones borrowing from a relative in month three.

So, what is the real number?

For a modest café outside London, build your plan around £50,000 to £80,000 and stress-test it against £100,000. If you inherit a good ex-café shell and stay disciplined, you can come in lower. If you take a bare unit and let the fit-out run, you will go higher, quickly.

The figures above are ranges, not promises. Prices move, sites differ, and your local quotes are the only ones that count. Use these as a frame to fill in with real numbers, not a substitute for getting them.

And if you are reading this because you have done it once already and are eyeing up a second site, the maths is only half the job the second time round. I have written a 90-day pre-launch checklist for opening a second café that covers the operational side the budget spreadsheet never shows you.

Ed O'Brien has run Hunters Cake Company for 17 years across cafés in Witney, Burford, and a bakery in Carterton, Oxfordshire. He's building Brikly - modular tools that give independent café owners the same data the big chains have, without the big chain price tag.