Plan a trip budget in two currencies, in one window

Planning a trip usually means three browser tabs: a currency converter, a time zone site and a calendar, plus a notes app where you add it all up. A plain-text calculator does all four in one window, and keeps the working so you can change it later.

Here is a real example: five nights in Berlin, planned in Zahl, a $5 calculator for the Mac. The same lines work for any trip.

Step 1: write down the costs as you find them

Give each cost a name. Prices can carry their currency, so you can write them exactly as you see them on the booking site:

// Berlin trip · 5 nights
flight = 240 eur
hotel = 95 eur * 5
food = 35 eur * 5

Zahl shows 240 EUR, 475 EUR and 175 EUR next to the lines. The comment line at the top is just a title, so you can tell your sheets apart later.

Step 2: add it up

flight + hotel + food        890 EUR

Because the costs have names, the total reads like a sentence. If the hotel drops its price, change the hotel line, and the total follows.

Step 3: see it in your own currency

prev to usd

prev means “the answer on the line above”. Zahl converts it using the European Central Bank’s rates, refreshed hourly. If you’re offline — on the plane, say — it uses the last rates it saved and shows their date next to the answer, so you always know how fresh the number is.

Any currency works the same way: 50 gbp in jpy, 200 cad to thb.

Step 4: dates and time zones

On the same page:

today + 12 days
9:30 am EST in Berlin        3:30 pm

The first tells you the date twelve days from now; the second, what time a 9:30 call back home is in Berlin. next Monday and today + 30 days work too.

Step 5: the small sums on the road

Restaurant bills, tax and tips are the sums you most often get wrong on holiday. Write them as you’d say them:

subtotal = 89.90
subtotal + 19% tax           106.98
15% tip on prev               16.05

And if you put a few amounts on consecutive lines, sum on the next line adds them up. A blank line starts a new block.

Keep the sheet

Sheets in Zahl save themselves, so the trip stays in its own tab until you delete it. Double-click the tab to name it. ⌘⇧E copies the whole sheet, calculations and answers, if you want to send it to whoever you’re travelling with.

For more on how this way of calculating works, see what a notepad calculator is.