Tax calculation for small teams

We end up explaining this on discovery calls often enough that it deserved writing down. Most advice about tax calculation assumes a team that does not exist at your size. Here is the version that does not.

In e-commerce every friction point has a price attached, and the arithmetic is unusually easy to check. It rarely shows up as a line item, which is exactly why it slips.

What to keep

Rules differ by destination and change without warning. Getting it slightly wrong is survivable. Ignoring it entirely is not. It is worth deciding this deliberately rather than inheriting whatever the last person set up.

What to drop

Process that exists to coordinate ten people is overhead when there are two of you. The cost of getting this wrong is rarely visible on the day it happens.

How we handle it

Automate it rather than maintaining tables by hand. In practice this is a scheduling problem more than a technical one. The practical test is whether someone new to the project could tell, in a minute, that it had been handled.

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

None of this needs a rewrite. Most of it is a morning's work once someone decides to do it.