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The Best Way to Merge Mercari and Facebook Marketplace Data for Tax Prep

If you're doing tax prep by hand right now, here's the fastest path from "two exports" to "one usable sheet," and why the manual version keeps breaking.

Step by step

  1. Decide your target columns once. Most people settle on Date, Channel, Order ID, and Total — set that up in CSV Experts and you won't redo it.
  2. Import the Mercari file first. The first time you see this file shape, you map each of its columns to your target list.
  3. Import the Facebook Marketplace file the same way. Its columns get mapped once too — after that, every future file with this shape merges with no extra clicks.
  4. Check the merged totals. Dates and numbers are normalized automatically, so a European "24,00" and a US "24.00" both land as the same value.
  5. Export. CSV or Excel, ready for tax prep.

What actually goes wrong if you do this by hand

Mercari gives you a sold date in the seller's local time, while Facebook Marketplace gives you an order date recorded through Meta's commerce backend — line those up manually across a few hundred rows and it's easy to miscount a week. On top of that, Mercari's export like other reseller apps, the export is minimal with no tax breakdown and mixes cancelled orders into the same file, and Facebook Marketplace's many sellers use Marketplace only for listings with no built-in checkout, so exports may only exist via a connected store's own platform. Individually those are minor quirks; combined into one spreadsheet by hand, they're where most reconciliation errors for tax prep actually come from.

Why it matters for tax prep

At tax time you need total revenue by channel without hand-fixing each export's columns first.

Try it with your own files →

Just want the quick column-difference reference instead? See the short version.

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