"Vi regner det ud."

Translation: We calculate it.

[epac-mcl]

"We'll work it out" is another way of saying it.
https://www.youtube.com/watch?v=g--Vlij1X1Y

[tonkotsuLover]

What is the use of "ud"?

[griffous]

It's a good question. A fixed phrase perhaps? Does anybody know?

[StephenHoy1]

Rejected "We are counting it out."

[epac-mcl]

When you count things, you count a row of things; like counting sheep to fall asleep, or counting apples to see how many you have. But when you calculate something you use an abstract process of reasoning, weighing things up against each other, using formulas etc.

"We calculate it", or "We work it out" is the usual English expression.

[StephenHoy1]

Better translation is "We figure it out." See Dansk Ordbog https://ordnet.dk/ddo/ordbog?query=Regner+den+ud

[epac-mcl]

"We figure it out" is yet another synonym, but Den Dansk Ordbog mentions only the Danish translation, and not the English/American.