LEGO Reselling Spreadsheet: Track Every Flip

A LEGO reselling spreadsheet is a tracking sheet, usually built in Google Sheets or Excel, that records what you paid for a set or minifigure, what you sold it for, and which fees came out of that sale so you always know your real profit instead of a guess. At minimum it needs columns for item name, purchase date, cost basis, marketplace, sale price, fees, shipping, and net profit, and it only works if you update it every time you buy or sell.

I started tracking every LEGO purchase and sale in a spreadsheet years before brick'em existed, mostly because I got tired of guessing whether a bulk lot actually made money once a marketplace's cut and shipping costs were factored in. In my experience, the sellers who turn this into real income, not just a hobby, are almost always the ones who know their numbers cold instead of the ones who "feel" profitable.

Key takeaways:

• A LEGO reselling spreadsheet should track cost basis, marketplace fees, shipping, and net profit for every item, not just the sale price.
• Fees vary a lot by platform. Promoted listings on eBay can push total fees close to 25% of a sale, while BrickLink's fees tend to run much lower.
• Bulk lots need a way to split one purchase cost across dozens of individual pieces so cost basis per item stays accurate.
• Manual spreadsheets work fine at first, but tools that automate purchase and value tracking start to pay for themselves once your inventory grows past a few hundred pieces.

What Should a LEGO Reselling Spreadsheet Track?

A LEGO reselling spreadsheet should track the item name and set or minifigure number, purchase date and cost, source, marketplace where it sold, sale price, fees, shipping cost, and final net profit. Those eight fields cover almost everything you need to know whether a flip actually made money once every cost is accounted for.

When I sort through a new haul, I write down the source first, whether it's a garage sale box, a Facebook Marketplace pickup, or a bulk lot off eBay, because that tells me how much digging I'll need to do to identify individual pieces. For loose minifigures without packaging, I'll cross-check names and numbers against brick'em's LEGO minifigure database before I ever add a row, since a misidentified figure throws off your cost basis math from the start.

Why Cost Basis Tracking Matters for LEGO Flips

Cost basis is simply what an item actually cost you, and it matters because it's the number you subtract from your sale price before fees to see if a flip was worth your time. Skip this step and you'll overestimate your profit on almost every sale, especially ones that came out of a bulk lot.

I learned this the hard way early on, tallying up a "successful" week of Whatnot sales only to realize a chunk of it was covering the cost of the bulk lot those pieces came from, not pure profit. A lot of sellers I know make the same mistake when they're starting out. They track revenue in their head but never actually subtract what they paid for the inventory in the first place, which makes every month look better than it is.

Splitting Cost Basis Across a Bulk Lot

To split cost basis across a bulk lot, divide the total price you paid by either the number of pieces or, more accurately, by the estimated resale value of each item relative to the whole lot. A flat per-piece split is faster, but a value-weighted split gives you a more honest profit number on your highest-value pieces.

Here's how I actually do it: I use brick'em's haul calculator to get a rough sense of what a mixed bulk lot is worth before I ever touch a spreadsheet, then I allocate my actual purchase price across each identified item based on its share of that estimated total. It's not perfect, but it's a lot more accurate than dividing evenly across 400 random pieces.

A Simple LEGO Inventory Spreadsheet Template

A simple LEGO inventory spreadsheet template needs one row per item and a fixed set of columns you never skip, even when you're in a hurry to list something. The table below is the exact structure I recommend to a seller I know who was starting her first Whatnot store this year.

Column	What to enter
Item / Set or Minifig #	Name and official LEGO number if known
Source	Bulk lot, Facebook Marketplace, garage sale, BrickLink, etc.
Purchase Date	Date you acquired the item
Cost Basis	Your allocated cost for this specific item
Marketplace Sold On	eBay, Whatnot, BrickLink, Mercari, Facebook Marketplace
Sale Price	Gross amount the buyer paid
Fees	Platform fees plus any promoted listing spend
Shipping Cost	What you actually paid to ship, not what buyer paid
Net Profit	Sale price minus cost basis, fees, and shipping

How Do You Track LEGO Profits Across Multiple Marketplaces?

You track LEGO profits across multiple marketplaces by adding a marketplace column to your spreadsheet and recording each platform's fees separately, since fee structures differ enough that a "good" sale on one platform can be a break-even sale on another. Grouping profit by marketplace at the end of each month shows you where your margin is actually coming from.

eBay has been the love of my life as a marketplace, and I've personally sold over $100,000 worth of LEGO through it over the years, but I'm honest about the tradeoff: to get real eyeballs on a listing you often need promoted placement, and between standard fees and promoted listing spend, your total take rate can creep close to 25% of the sale. Whatnot works differently. It periodically runs no seller fee days, and I've found that spending around $20 per show on boosted promotion near the start of a live sale helps pull in early viewers who then stick around. BrickLink usually comes out cheaper on fees than either one, which is part of why so many sellers use it as their pricing reference, almost like the Wall Street of LEGO, even when they're not listing there.

Using a LEGO Reselling Spreadsheet for Bulk Lot Breakdowns

A LEGO reselling spreadsheet earns its keep most clearly on bulk lot breakdowns, where one purchase turns into dozens of individual listings across different marketplaces. Without a spreadsheet, it's almost impossible to remember which of those 40 minifigures actually sold for a profit and which ones you're still holding at a loss.

Facebook Marketplace is where I source a lot of these lots, since people getting rid of old bins of LEGO rarely know what they have. When I buy a lot there, I add every identifiable item to my sheet the same day, even the pieces I plan to hold, because prices move and I'd rather have a record of what I paid than try to reconstruct it months later from memory.

Should You Use a Spreadsheet or an App to Track LEGO Inventory?

A spreadsheet is fine for tracking LEGO inventory when you're moving a few dozen items a month, but it starts to break down once you're sourcing bulk lots regularly and juggling hundreds of pieces across multiple marketplaces at once. At that point, manual data entry becomes the bottleneck, not sourcing or selling.

This is exactly the gap brick'em was built to close. Instead of typing every column by hand, you can scan a bulk lot of minifigures, get identification and pricing support automatically, and export the results straight into an inventory you can track and list from. If you want to see whether your current collection or a recent haul is worth the spreadsheet effort in the first place, brick'em's LEGO collection value calculator is a fast way to check before you commit to entering everything by hand. You can sign up for brick'em free to try the scanning and tracking workflow on your next haul.

Should Sealed Sets Get Their Own Tracking?

Sealed sets should generally get their own section or tab in your spreadsheet because you're usually holding them longer than a typical minifigure flip, and the numbers you care about are different. Purchase date and expected holding period matter more than fast turnaround.

I'm personally a big believer in sealed sets as a longer-hold category, partly because of the box art and display value collectors pay for, and partly because the category has held up well against other investment types in research I've seen cited in the community, though results vary a lot by set and you should verify current sold prices before assuming any specific set will appreciate. For sets you're tracking as a longer-term hold, brick'em's LEGO investment calculator is a useful companion to a spreadsheet tab, since it's built specifically around that appreciation question rather than quick flip math.

Common Mistakes When Building a LEGO Business Spreadsheet

The most common mistake when building a LEGO business spreadsheet is tracking revenue without cost basis, which makes every sale look profitable even when it isn't. The second most common mistake is forgetting shipping and packaging costs, which quietly eat into margin on lower-priced items.

• Not recording cost basis per item, only total revenue
• Forgetting to subtract shipping supplies and postage from net profit
• Lumping all bulk lot items together instead of splitting cost basis
• Not separating fees by marketplace, which hides which platform is actually most profitable
• Letting the sheet go stale for weeks instead of updating it after each sale

A LEGO Reselling Spreadsheet Checklist Before Your Next Sale

Before you list your next item, run through a short checklist to make sure your spreadsheet actually reflects reality instead of a rough estimate from memory. I use a version of this list myself before closing out a Whatnot show or a big eBay week.

• Every item has a cost basis entered, not left blank or estimated after the fact
• Bulk lot purchases are split across individual items, not lumped as one line
• Marketplace and fee percentage are recorded for each sale
• Shipping cost is the actual amount paid, not the amount charged to the buyer
• Net profit is calculated per item, not just as a total at the bottom of the sheet
• The sheet has been updated within the last week, not left stale from a busier month

Frequently Asked Questions

Do I need a LEGO reselling spreadsheet if I only sell a few sets a year?

If you're only selling a handful of sets a year, a full spreadsheet system is probably overkill, but I'd still recommend jotting down what you paid and where each item came from. It takes a few minutes and saves you from guessing at profit later, especially around tax season when you need accurate records.

What's the best free tool for a LEGO inventory spreadsheet?

Google Sheets is the free tool I recommend most often, since it's accessible from your phone when you're sourcing on the go and easy to share with a partner or co-seller. Excel works too if you already use it, but real time mobile access is the bigger advantage for most resellers.

How do I track LEGO profits when items sell across eBay, Whatnot, and BrickLink?

Add a marketplace column and record fees separately for each platform, since eBay, Whatnot, and BrickLink all charge differently. Reviewing profit grouped by marketplace at month end shows you which platform is actually earning you the most after fees, not just which one moves the most volume.

Should I track incomplete or damaged LEGO sets differently?

Incomplete or damaged sets are worth their own notes column, since you'll often need to source missing pieces on BrickLink before reselling. I've seen sellers turn overlooked, dirty inventory into solid margin once cleaned and completed, so don't skip logging these as real inventory just because they need extra work.

How often should I update my LEGO reselling spreadsheet?

I recommend updating your spreadsheet the same day you buy or sell something, not in a weekly batch. From what I've seen, sellers who batch updates almost always forget small fees or shipping costs, which quietly makes their profit numbers look better than they really are.