Reselling inventory spreadsheet: the columns that answer real questions

The notebook that couldn't answer a question

Most resellers start with a notebook or the notes app: "Blue jacket, $8, Goodwill." It works for twenty items. At two hundred, simple questions stop having quick answers. What did I pay for the jacket that just sold? How much stock have I had for more than six months? What did shipping actually cost me last month? A spreadsheet with the right columns answers all three in seconds, and it doesn't need formulas beyond addition and subtraction.

This guide builds a reselling inventory spreadsheet, based on IRS guidance on what records to keep and how to record business transactions, and IRS Publication 538 on inventories, checked November 8, 2026. It's a practical records template, not tax advice.

What the IRS says a record system needs

The IRS says you may choose any recordkeeping system suited to your business that clearly shows your income and expenses, and that electronic records must meet the same requirements as paper ones. It lists supporting documents such as sales slips, paid bills, invoices, receipts and deposit slips, and describes purchases as the items you buy and resell to customers. The IRS transactions page suggests recording expenses when they occur, identifying the sources of income, and generally recording transactions daily.

A spreadsheet is the summary; the receipts and platform reports are the evidence behind it. Keep both. The tax records manual covers what to keep and for how long.

Step 1: Set up the columns

One row per item. These are the columns that answer the most questions:

Step 2: Add the one calculated column

Add a "Surplus" column: sale total received minus cost minus fees minus label and packing. It isn't profit in a tax sense, because it ignores your time, supplies bought in bulk, mileage and other overheads, but it shows which items earned their space. The payout is not profit manual explains the difference.

Worked example: one row from purchase to sale

In this chosen example, a sweater bought for $6.00 sells for $40.00 plus $8.00 shipping paid by the buyer.

The fee and label amounts are examples, not any platform's current rates. Use the numbers on your own sale record. The calculator below runs the same arithmetic with your figures.

Step 3: Use status values consistently

Pick a short list of status words and never improvise: Intake, Untested, Listed, Sold, Shipped, Returned, Donated, Discarded. Filtering by status then gives you instant lists, such as everything still untested, or everything sold but not shipped. A data validation dropdown in most spreadsheet apps keeps the words consistent.

Step 4: Record sales the day they happen

Fill the sale row when the order arrives, not at the end of the month. Copy the fee and shipping figures from the platform's order page. Daily entry matches the IRS suggestion to record transactions as they occur, and it's much faster than reconstructing a month from statements.

Step 5: Add a second tab for non-item costs

Supplies, mileage, storage and subscriptions don't belong to one item. Keep them on a separate tab with date, description, amount and category. The mileage records guide covers what a mileage log needs.

Step 6: Review monthly

Once a month, sort by date acquired and look at anything unsold for six months or more. Filter by source to see which stores produce your best surplus. Total the sold rows' fees and labels to check your shipping charges are covering costs. The stocktake guide explains checking the sheet against the shelves.

Back it up: Keep the spreadsheet in a place that's backed up automatically, and save a dated copy at the end of each month and year.

Keep personal data out

Don't record buyer names or addresses in the sheet. Order numbers are enough to find a sale in the platform if you need the details.

Common mistakes

• Recording only the item price and not the shipping the buyer paid.
• Leaving fees and labels blank and estimating later.
• Using different words for the same status.
• Mixing supply purchases into item rows.
• Treating the surplus column as taxable profit.

Twelve columns and a habit

A spreadsheet only answers questions if every sale is entered the day it happens. Set the columns once, keep status words consistent, and review the sheet monthly against the shelves.