Three stores. Three CSV formats. One number you can trust.

If you sell on Shopify and Etsy and Amazon, "how much did I make last month" is not a number you can look up. It's an afternoon in a spreadsheet.

Every store exports differently. Shopify calls it Lineitem name, Etsy calls it Item Name, Amazon calls it item-name. One file is comma separated, one is tab separated, one arrives with $1,250.00 as text. Refunds are marked three different ways. And the gross number none of them agree on still isn't what hits your bank, because each takes a different cut.

So you paste them into one sheet and fix it by hand. Every month. Same steps.

What this does

The same five steps, in one command:

1. Reads every CSV in the folder — any encoding, comma or tab separated
2. Maps each store's column names to one set
3. Drops cancelled, refunded and returned rows
4. Totals by product and by channel
5. Applies your fee rates so you see net, not gross

$ python settle.py

==============================================================
  MONTHLY SETTLEMENT
==============================================================
  files read : 3
  rows kept  : 5
  rows out   : 3  (cancelled / refunded / returned)

  BY CHANNEL
  ----------------------------------------------------------
  Etsy                          5,000.00   fee  6.50% ->       4,675.00
  Amazon                          236.00   fee 15.00% ->         200.60
  Shopify                          87.00   fee  2.90% ->          84.48
  ----------------------------------------------------------
  GROSS                         5,323.00
  NET                           4,960.08   after fees

Nothing is uploaded

This is a single Python file that runs on your computer. There is no account, no API connection, no server. Your order data — customer names, addresses, revenue — never leaves the machine you run it on.

That is also why there is nothing to cancel. It is a file, not a subscription.

It refuses to guess

This is the part that matters, and it is the opposite of what most spreadsheet templates do.

If a file has no column the tool recognises as the amount, that file is listed as skipped and left out entirely:

SKIPPED FILES  (nothing was guessed — these were left out)
  myshop.csv — no column found for: amount

It also prints every header it ignored, so you can check your real amount column didn't land in the wrong bucket.

A wrong total that looks right is worse than a missing one. You act on a wrong total. You investigate a missing one.

Setup

Python 3.6 or newer. Standard library only — nothing to install. Already on every Mac; Windows users get it from python.org.

What it does not do

• No sales tax or VAT calculation — that's an accountant's job
• No inventory or fulfilment tracking
• No connection to your store — it reads files you exported

Fee rates are your numbers. Marketplaces change rates and add per-order and payment-processing charges that no single percentage captures exactly. Treat NET as a planning estimate; your settlement report from each store is the number of record.

Doing it by hand this month? The four places multi-channel totals silently go wrong walks through the same six steps in a spreadsheet.