Profit, fee and stock math

A product can have strong demand and still lose money. Profit, fee and stock tools work out what is left after the marketplace takes its share, after fulfillment, storage, returns, ad spend and the cost of getting goods to the warehouse. Some do this for one product before you buy it. Others track every sale after launch and tell you when to reorder.

Before buying, a fee calculator is the quickest check. Enter the price, size and weight and you see referral and fulfillment fees, and what remains for product cost, freight and ads. Resellers use calculator extensions on every product they consider, since a margin that looks healthy at the shelf price can disappear once fees for an oversize item are included. Private-label sellers run the same math at their target price, then again at the lower price they might need to compete.

After launch, profit dashboards connect to your seller account and pull in sales, fees, refunds, storage charges and advertising, then subtract the costs you enter. They show which products actually earn money, which ones are kept alive by ads, and where fees have changed. Many also spot reimbursements the marketplace owes for lost or damaged stock.

Featured AI product research tools: profit, fee and stock math

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7 AI product research tools in profit, fee and stock math

Sellerboard

Profit dashboard for Amazon sellers that subtracts fees, ad spend and product costs and tracks stock levels.

Works with Amazon data

Shopkeeper

Amazon profit analytics that breaks down fees, refunds and costs by product and marketplace.

Works with Amazon data

InventoryLab

Listing, inventory and accounting tool for Amazon FBA sellers, with a mobile scouting app.

Works with Amazon data

SoStocked

Inventory forecasting for Amazon sellers that plans reorders and FBA shipments from sales history.

Works with Amazon data

FBA Revenue Calculator

by Amazon

Free Amazon calculator that compares fees and estimated margin for fulfilling an item yourself or through FBA.

Works with Amazon data
Free plan or free tier

SellerAmp SAS

by SellerAmp

Sourcing calculator and browser extension for Amazon resellers that checks fees, profit, rank and restrictions.

Works with Amazon data
Browser extension

BuyBotPro

Deal analysis extension for Amazon resellers that runs profit, fee and risk checks on a product page.

Works with Amazon data
Browser extension

Inventory planning is the other half. Running out of stock costs sales and can hurt search rank, while too much stock costs storage fees and ties up cash. Forecasting tools use sales history, lead times and shipping times to suggest when and how much to reorder, and some plan shipments into fulfillment centers.

When you compare tools here, check that they handle every cost you have, including freight, duties, packaging, prep services and returns. Make sure they cover each marketplace and country you sell in, since fees differ. For dashboards, see how they treat costs that change over time, such as a new freight rate on a later batch. The output is only as accurate as the costs you enter, so keep them current.

Advertising is the cost sellers most often underestimate. A new listing usually needs paid ads to collect its first sales and reviews, and the cost per sale in that period can be much higher than later. Build a launch budget into your numbers and decide in advance how long you will spend before the product needs to pay for itself.

Questions about profit, fee and stock math

What fees should I include when checking a product's margin?

Referral or selling fees, fulfillment fees, monthly and long-term storage, ad spend per sale, returns, packaging, prep, freight to the warehouse and import duties. Missing any of them makes a product look more profitable than it is.

Why does my profit dashboard differ from my payout?

Payouts include timing differences, reserves and charges from other periods, while dashboards usually match costs to the day of the sale. Both can be correct. Reconcile them monthly against your marketplace statements.

How do inventory forecasting tools decide when to reorder?

They take recent sales speed, your supplier's lead time, shipping time and a safety buffer, then work out the date stock would run out and count back. Check their assumptions before peak seasons, when sales speed changes.

Are reseller calculator extensions accurate?

They use the marketplace's published fee rules, so the fees are usually close. Product dimensions on a listing can be wrong, which changes fulfillment fees, so check the size tier when a margin looks borderline.