Check what Amazon paid you, and know your real margin.
Free audits and calculators for Amazon US sellers — check reimbursements, lost units, returns and settlements, plus profit, break-even ACOS and FBA vs FBM. You use your own reports and numbers; everything runs in your browser and nothing is uploaded.
Free · no account · nothing leaves your browser
FBA profit & break-even ACOS
Net profit, margin, ROI, break-even ACOS and break-even price from your own price, cost and fees.
Open AdvertisingPPC / ACOS calculator
Your break-even ACOS and ROAS, whether your current ACOS is profitable, and the target ACOS for a profit goal.
Open FulfillmentFBA vs FBM
Net profit per unit for Amazon fulfillment vs shipping it yourself, side by side. See which wins.
Open ReconcileSettlement report analyzer
Drop in your Amazon settlement report and see profit per SKU. The file is read in your browser, never uploaded.
Open ReconcileFBA reimbursements analyzer
See what Amazon reimbursed for lost, damaged and fee-corrected units — by reason and SKU, reversals included.
Open RecoverLost & damaged inventory finder
Check Amazon actually paid for units it lost or damaged — ledger vs reimbursements, with the 60-day deadline. No login.
Open RecoverRefunded-but-not-returned finder
FBA refunds where the item never came back and Amazon hasn't reimbursed you — with the day-45-to-105 claim window.
Open InventoryReorder point & safety stock
When to send your next FBA shipment and how many units, from your daily sales and supplier lead time.
Open TaxFBA sales-tax state map
Which US states your FBA inventory may require sales-tax registration in — 51 jurisdictions, each cited to the state.
OpenGet the free Chrome extension — profit and break-even ACOS on any Amazon.com product page, with the price filled in from the page.
Your own numbers
No Amazon fee tables are hard-coded — you enter your category's referral rate and your FBA fee, so the maths is right for your product and stays right when Amazon changes rates.
Runs in your browser
Every tool on this page runs in your browser. Your figures, and any report you open, stay on your device and are never uploaded.
No account, no catch
Nothing you need to install and nothing to buy. Open a tool, type your numbers, get the answer.
More is coming — free for the first sellers
I'm building WidenMargin to track profit, fees and break-even across all your Amazon products automatically. Join the early-access list and I'll email you when it's ready. The calculators here stay free.