A short guide to tax calculation

The version of this that works is simpler than the version most people imagine. Everything we would tell a client about tax calculation in the time it takes to drink a coffee.

In e-commerce every friction point has a price attached, and the arithmetic is unusually easy to check. Check it against what you would want a competitor's site to get wrong.

What it costs to ignore

Rules differ by destination and change without warning. None of that requires a large budget, only a decision and someone to own it. The practical test is whether someone new to the project could tell, in a minute, that it had been handled.

The practical version

Getting it wrong is a compliance problem, not just an accounting one. That sounds obvious written down. It is still the thing most often skipped. The practical test is whether someone new to the project could tell, in a minute, that it had been handled.

Where it usually goes wrong

Automate it rather than maintaining tables by hand. The reasoning matters more than the rule, because the rule has exceptions. If two people in the business would answer this differently, that gap is the actual problem.

The short version

Trust does most of the selling online, and trust is built from unglamorous details. Three things worth confirming about tax calculation before you move on:

• Someone can say what the current setup is without going to look
• Getting it wrong is a compliance problem, not just an accounting one — and you know whether that is true here
• There is a way to tell whether the last change to this helped

If you want a second opinion on how yours is set up, ask.