Lease Deal True Cost Calculator

Two thousand square feet at twenty-eight dollars a foot. Nine months rent-free. It sounds like a good deal and the arithmetic says the space costs forty-six dollars and sixty-five cents a foot a year.

The headline rent describes 59.81% of the bill. The rest is the service charge, the rates and the fit-out, and they are quoted separately, later, or not at all.

The rent-free period is the part that misleads hardest. Nine months off a ten-year term is 7.50% of the rent — and the review in year five lifts the rent by fourteen per cent for half the term. Put both through the arithmetic and the effective rent is twenty-seven dollars and ninety cents, ten cents a foot below the headline. The incentive that was negotiated hardest is worth almost exactly nothing.

Change the review to nothing and the same nine months is worth two dollars and ten cents a foot. Same incentive, same lease, entirely different answer, and the difference is a clause that gets one line in the heads of terms.

The break clause is costed separately, over the years you would actually be there. Leaving at year five spreads the fit-out over half as many years and adds the penalty on top, so on these figures breaking costs forty-nine dollars and ten cents a foot — dearer per year than staying the full term. That does not make it the wrong move. It makes it a priced one, which is more than most people have when they take the option.

The comparison screen is where this earns its keep. Two leases are almost never quoted on the same basis: one has a longer rent-free, one has a lower service charge, one has a review two years earlier. Put them side by side on cost per square foot per year and the question stops being which rent is lower.

There is no dilapidations figure on this page. What a landlord will ask for at the end of a term is not knowable at the start of one, and a number invented for it would be the largest guess here. It is left out and named rather than estimated.

It does not tell you whether to sign, and it has no view on whether the rent is the market rate. Nothing here knows what the space is worth. What it knows is what the paperwork adds up to over the term, which is a different question and the one nobody works out.

Save as many versions as you like and put any two side by side, figure against figure, with the better one on each line marked and the difference in its own column. That screen is the one that decides things, and it is the part a free calculator cannot do at all. Two leases are almost never quoted on the same basis, and this is the screen that puts them on one.

One HTML file. No account, no subscription, no internet needed. Opens on Windows, Mac and Android; the readme explains the extra step on iPhone and iPad, where Apple blocks JavaScript in downloaded files and every tool of this kind is affected.

Everything lives in your browser on your device. Nothing is uploaded, which is why it works offline and why nobody else can see your figures — and it also means clearing your browsing data deletes it. The tool does not pretend otherwise: the header shows how long since your last export at all times, turns amber after three days and red after seven, and export is one click that produces a plain file you keep.