Flip Profit Calculator

What a flip earns and what it keeps

Buying low and selling high is the headline. The number that matters is what falls out at the bottom, and it is always smaller than the gap between the two prices. A $40.00 item sold for $95.00 looks like $55.00 of profit, and it is not.

Between those two prices sit five things: the platform commission, the payment processing charge, the shipping label, the packaging, and whatever share of your sales comes back as returns. On the numbers above they total $26.65, which is 28.1% of the sale price. The profit that survives is $28.35, not $55.00.

That gap is why two sellers can report opposite results on the same item. One counts only the cash that changed hands at the counter. The other counts the commission, the box, the tape and the label, and the second one is the one who is still selling in a year.

The calculator takes the second view. Every field in it is a cost somebody has to pay, and the profit line is what is left after all of them.

The formula behind the calculator

The calculation is a single subtraction with five terms, and it runs the same way for a sneaker, a textbook or a power tool.

• Net profit = sale price - (cost of the item + platform commission + shipping + packaging + return reserve)
• Platform commission = sale price x commission rate
• Return reserve = sale price x return rate
• Margin = net profit / sale price x 100
• Return on spend = net profit / total cost x 100
• Break-even price = (cost of the item + shipping + packaging) / (1 - commission rate - return rate)

Two of those deserve a note. The return reserve is not a fee anybody bills you. It is your own money held back so that a refund in month three does not come out of a different month's income. Five percent of the sale price is a common starting point, and it goes up with categories where buyers return more.

The break-even price is the one people forget. It tells you the lowest price at which the flip is worth doing at all, and it rises faster than you expect, because the commission and the reserve both grow with the sale price. On this example the break-even price is $60.85, which is 52% above the $40.00 cost.

Worked example: buy at $40, sell at $95

Here is the default example in the calculator, broken down line by line. One unit, sold after 45 days, with a 12% commission and a 5% return reserve.

Run the same flip five times and it scales cleanly: $475.00 of revenue, $333.25 of total cost and $141.75 of profit. That is the number worth comparing against a weekend of overtime, because it is what the whole batch earned.

The return has a second version worth watching. Measured against the $40.00 purchase price alone, ignoring the fees and shipping, the profit is a 70.9% return. Measured against the $66.65 you spent, it is 42.5%. Both are correct, and the second is the one that describes your money.

The two return measures disagree on this flip, and the difference is the point of having both. The margin is 29.8% of revenue, which is the number to compare against retail benchmarks. The return on everything you spent is 42.5%, which is the number that tells you how hard your money worked.

Every cost that eats into a flip

Most failed flips do not fail on the sale price. They fail on a cost that nobody wrote down, and the list below is where those hide.

• Platform commission. Usually 8% to 15% of the sale price, sometimes higher in a specific category. Rates move, so read the fee page for the platform you list on, such as the eBay selling fees page, rather than assuming last year's number.
• Payment processing. Often a percentage plus a fixed amount per order, and it applies to the whole amount the buyer paid, shipping included.
• Shipping label. Weight and distance decide it. A $8.50 label on a $95.00 sale is 8.9% of revenue, which is more than most people guess before they weigh the box.
• Packaging. Boxes, tape, mailers and printer ink. Around $1.00 to $4.00 a parcel for most small goods.
• Returns and cases. The refund itself, the return label, and the item coming back unsellable. A 5% reserve covers a stable category; a 10% reserve is nearer the mark for apparel and electronics.
• Sourcing overhead. Fuel, mileage, entry fees at a yard sale or a storage unit monthly fee. It is real money with no receipt attached to the item.
• Your time. Not a deductible cost, but the reason a $28.35 profit can be a bad deal. Three hours of work on one unit is $9.45 an hour before tax.

The habit that fixes most of this is pricing at the listing stage. Work the numbers before you buy, not after the item sells, and a thin flip becomes a decision rather than a surprise.

Three flips compared

Profit in dollars and profit as a percentage tell different stories. These three flips all made money, and only two of them were worth the shelf space.

The tablet produced the biggest single sale and the worst result. It tied up $150.00 of capital for a $27.00 profit, and its 11.3% margin leaves almost nothing for a return, a price drop or a buyer who changes their mind. The textbook made less money and did far more with it, because $43.40 of capital is easier to find five times over.

That is the case for judging flips on the return rather than the dollars. Twenty textbook flips at $26.60 each is $532.00 on $868.00 of capital. Five tablet flips at $27.00 each is $135.00 on $1,065.00 of capital, and it takes longer.

ROI versus annualized ROI

Annualizing a flip is where the numbers stop being useful, and it is worth understanding why before you quote one. The formula takes your return per flip and compounds it across as many turns as would fit in a year.

Every row is the same flip, returning 42.5% on money spent. The annualized column assumes you can repeat it perfectly, at the same margin, forever, with capital that never runs out and stock that always sells. None of those hold in a bedroom operation.

The scaled column is the honest one for planning. It multiplies the return by the number of turns and ignores compounding, so a 45-day flip reads as 345% rather than 1,672.1%. Even that assumes you find a replacement item the day the last one ships.

What annualized ROI is good for is ranking. Two flips with the same dollar profit are not equal if one turns in three weeks and the other in six months, and that comparison survives even when the headline percentage does not.

Break-even price and the return reserve habit

The break-even price is the number that should decide whether you list at all. On this example it is $60.85: below that, the commission and the reserve eat the margin and the sale loses money even though cash arrived.

It is higher than most people expect because two of the costs scale with the sale price. Raise the price and you also raise the commission and the reserve, so you never catch up from a bad starting point. Raising the commission rate from 12% to 15% on the same flip drops the profit from $28.35 to $25.50, and it lifts the break-even price with it.

The reserve deserves a habit rather than a one-off decision. Put a fixed percentage of every sale into a separate account and do not count it as income. At 5% the reserve on a $95.00 sale is $4.75. If your category returns at 10%, the same flip nets $23.60, and knowing that before you buy is the difference between a business and a hobby.

Shipping is the other lever. If the buyer pays the label instead of you, the profit on this flip goes to $36.85. That is $8.50 of margin recovered without touching the price, and it is why a shipping charge is worth more than a small price cut.

Taxes, records and what the IRS sees

Profit from reselling is income. If you buy with the intent to sell for more than you paid, the gain is business income, and the costs that produced it are deductible. That is the short version, and the paperwork is where it gets real.

The IRS instructions for Schedule C set out how a sole proprietor reports income and expenses, and the IRS page on business income covers the same ground in plain language. Platform forms such as a 1099-K report gross payments, so your own records are what turn that gross figure into a profit figure.

Keep four things for every item: what you paid, where you paid it, what you sold it for, and every fee attached to the sale. A folder of screenshots and receipts, one line per item, turns a year of flipping into a form you can fill in an evening rather than a weekend of guessing.

Set aside tax as you go. A common approach is to hold 25% to 30% of profit for federal and state tax plus self-employment tax, and to move it out of the spending account the day the sale clears.

This is an estimate for planning, not tax advice. Fee schedules and tax rules change, and thresholds for platform reporting move with them. Confirm the details with the IRS pages linked above or a tax preparer before you file.