How to track profit on PC flips (and the spreadsheet you outgrow)

Ask a flipper what their last machine made and you will usually get a quick, confident number. Ask how they worked it out and the answer is almost always the same: they added up what the parts sold for and took off what they paid.

That number is nearly always wrong, and it is wrong in the flattering direction. It leaves out the fees, the courier, the thermal paste, and the power supply still sitting under the desk. On a fat margin the error does not matter much. On the margins of 2026, where flipping is still worth it but less forgiving, it is often the difference between a profitable month and a busy one.

This is how to track what your flips actually make, the spreadsheet layout that works while you are small, and the signs that you have outgrown it.

What does profit on a flip actually include?

Profit on a flip is everything that came in, minus everything that went out, for that one purchase. Written out, per sale:

• In: the price it sold for
• Out: the selling fee, the shipping or courier, and the share of the purchase price that part carried in

Then, once per purchase:

• Out: consumables and replacements you spent getting it ready, such as thermal paste, isopropyl, a fan, a Windows licence or a replacement power supply

Two things are deliberately missing. Your time is one, and it belongs in a separate number (more on that below). Unsold stock is the other. A part you still own is not profit and it is not a loss yet. It is cost you have not recovered, and it needs its own line so it cannot hide.

How do you split one purchase across its parts?

This is where most tracking falls apart, because a used PC comes in as one price and leaves as five or six sales. To know which sales made money, every part needs its own cost, known as its cost basis.

The fair way to split it is in proportion to what each part should sell for. You already worked those numbers out when you valued the machine before buying, so reuse them:

1. List every part with a realistic resale value.
2. Add those values up.
3. Divide what you paid by that total.
4. Multiply each part’s resale value by the result.

Here is a real-shaped example, in whatever currency you sell in. You buy a gaming PC for $600, and its parts should fetch about $700 between them. $600 divided by $700 is about 0.857, so each part carries roughly 86 percent of its expected value as cost.

Part	Expected resale	Cost basis
RTX 3070	$350	$300
Ryzen 5 5600 + B550 board	$180	$154
16GB DDR4	$50	$43
1TB NVMe drive	$50	$43
650W power supply	$50	$43
Case	$20	$17
Total	$700	$600

Splitting this way has a useful side effect. A part that sells for about what you expected shows a small, fair profit. A part that sells badly shows a loss on its own line, which tells you exactly where your valuation was off, instead of smearing the mistake across the whole machine.

A worked flip, from purchase to the honest number

Now say you spend $12 on paste and cleaning supplies, and over the next six weeks this happens:

• The graphics card sells on a marketplace for $360, with a $36 fee and $15 shipping, so $309 actually lands.
• The CPU and board go together at a local pickup for $190.
• The RAM sells locally for $55 and the drive for $50.
• The power supply and the case are still on the shelf.

The quick version says the parts sold for $655, you paid $600, so you made $55.

The honest version:

	Amount
Money in, after fees and shipping	$604
Cost basis of the parts that sold	$540
Profit on what sold	$64
Consumables	$12
Profit so far	$52
Cost still on the shelf (PSU and case)	$60

And the line that matters most for a small operation: in cash terms, you are $8 down. You paid $612 all in and $604 has come back. The $52 profit only becomes real money if the power supply and case sell for at least the $60 of cost they are carrying.

That is not a bad flip. It is a normal one. But “I made $55” and “I am $8 down until a PSU and a case sell” lead to very different decisions about what to buy next, and only one of them is true.

The spreadsheet that works while you are small

You do not need software to start. You need a structure that forces every part to carry its cost. Two tabs are enough.

Purchases tab. One row per thing you bought:

• Purchase ID, date, where from
• Total paid
• Consumables spent on it
• Notes (what was wrong with it, who sold it)

Parts tab. One row per part that came out of a purchase:

• Part ID and the Purchase ID it came from
• Description, with model and capacity
• Expected resale value
• Cost basis
• Status: in stock, in a build, listed, sold
• Sold date, sale price, where it sold
• Fee and shipping on that sale
• Profit

The cost basis column does the proportional split for you. Assuming the Purchase ID is in column B, expected value in column E, and total paid in column D of the Purchases tab, it looks like this:

=E2 / SUMIF(B:B, B2, E:E) * VLOOKUP(B2, Purchases!A:D, 4, FALSE)

Profit per part is then the sale price minus fee, minus shipping, minus cost basis. A pivot or SUMIF on Purchase ID gives you the profit for each flip, and a filter on status gives you what is still on the shelf.

Add two more columns once you have a few flips behind you, because they answer the questions that make you better at buying:

• Days to sell. The sold date minus the purchase date. Parts that take months to move are tying up cash, however good the profit looks.
• Hours spent. A rough figure per purchase. Divide profit by it to get a return per hour, which is the number that tells you which kinds of machines are worth buying again.

Where the spreadsheet breaks

The spreadsheet above works as long as each purchase splits into a handful of sales and then closes. It starts to lie, slowly and quietly, when any of these happen:

Parts from different purchases end up in one build. The RAM from one machine, the card from another and a new power supply go into a build you sell whole. Now one sale has to pull cost from three purchases, and a flat sheet has no clean way to say so. Most people end up typing a number in by hand, which is the moment the sheet stops being a record and starts being a guess.

A part moves between builds. You put a card in one build, pull it for another that sells sooner, and the first build gets a different card. Unless you update every row involved, the cost follows the wrong machine.

Prices change before the sale. A part listed at $80, relisted at $65 on a different site with a different fee. The sheet only keeps the last version, so you lose the history that tells you your first price was too high.

Leftovers never get dealt with. The case and the power supply sit at full cost forever, and every summary looks healthier than your bank account. A sheet will not nag you that something has been on the shelf for ninety days.

More than one person touches it. Two people, one sheet, and nobody quite sure who marked what as sold.

You are at a pickup, not a desk. The best moment to record a part and what you paid is standing in someone’s driveway. Shared spreadsheets on a phone are technically possible and practically miserable, so it gets done later, from memory, slightly wrong.

None of these are rare. They are what happens as soon as flipping becomes something you do every week instead of every few months, and especially once you start building sellable machines from stock instead of only parting things out.

What to look at once you are tracking properly

Good records are only worth keeping if they change what you do. These are the numbers worth checking every month:

• Profit per purchase, sorted. Your best and worst five flips usually have something in common, a seller type, a platform, a kind of machine.
• Margin on cost. Profit divided by what you paid. A $40 profit on a $100 office PC is a better buy to repeat than $60 on a $700 gaming machine.
• Return per hour. The honest answer to whether a kind of flip is worth your weekend.
• Cash on the shelf. The total cost basis of everything unsold. If that number keeps growing, you are buying faster than you are selling.
• Aged stock. Anything older than sixty days needs a decision: reprice it, build it into something, or write it off. If you are holding parts back for a better price, check it against the seasonal selling window rather than waiting indefinitely.

That last habit alone fixes most of the gap between what flippers think they made and what they actually made.

Doing this more than once

If you flip a machine every couple of months, the two-tab spreadsheet is enough. Keep it honest, split every purchase, and count the leftovers.

If you are flipping every week, the work the spreadsheet cannot do becomes the work that eats your margin. PartPlanner was built for exactly that point. You log a purchase as it lands, from your phone at the pickup if you like, and break a bought PC into its parts with the cost basis spread across them. Parts move into builds and the running cost follows them, whichever purchase they came from. When something sells you mark it sold, fees and all, and the profit on that part, that build and that purchase is something you look up rather than reconstruct on a Sunday night.

You can check what a machine is worth with the free PC part value calculator before you buy it, and start tracking in PartPlanner on the free plan, no card required. Whichever you use, the rule does not change: every part carries its real cost from the day you buy it to the day it sells, and anything still on the shelf is not profit yet.