What to ask your agency about tax calculation

There is no clever trick in this one, just a handful of decisions worth making deliberately. If you are briefing an agency or a freelancer on tax calculation, these questions are worth asking early.

In e-commerce every friction point has a price attached, and the arithmetic is unusually easy to check. Budget a little time for it every quarter and it never becomes a project of its own.

Questions worth asking

• Who will actually do this work, and have they done it before?
• How will we know afterwards whether it worked?
• What happens if it needs changing in a year?
• What are you assuming that we have not confirmed?

What a good answer sounds like

Rules differ by destination and change without warning. In practice this is a scheduling problem more than a technical one. The failure mode is not doing it wrong, it is doing it once and assuming it stays done.

Automate it rather than maintaining tables by hand. That sounds obvious written down. It is still the thing most often skipped. Anything you cannot measure here, you are deciding by taste, which is fine as long as everyone knows it.

In practice

Small percentage changes matter here because they apply to every order, every month. Three things worth confirming about tax calculation before you move on:

• Someone can say what the current setup is without going to look
• Rules differ by destination and change without warning — and you know whether that is true here
• There is a way to tell whether the last change to this helped

Worth checking on your own setup before it becomes someone else's problem to fix.