Free Tools & Calculators for UK Resellers
Make smarter sourcing, pricing, marketplace, shipping and business decisions with practical tools built around the numbers that matter to UK online sellers.
What Are You Trying to Work Out?
Choose the situation that best matches what you are trying to decide and jump straight to the most useful SellerStack tool.
Know Your Numbers Before You Sell
Calculate profit, ROI, break-even points and safe buying or selling prices before committing money.
Reseller Profit Calculator
Calculate true profit after stock cost, fees, fulfilment and other selling expenses.
Calculate Profit →Reseller ROI Calculator
Measure how efficiently your stock investment could generate profit.
Calculate ROI →Break-even Calculator
Find the minimum selling price needed to cover your entered costs.
Find Break-even Price →Product Pricing Calculator
Set a selling price that protects your desired profit and margin.
Calculate Selling Price →Maximum Buy Price Calculator
Work backwards from your expected sale to determine the highest safe price to pay.
Find Maximum Buy Price →Bundle Pricing Calculator
Create an attractive bundle price without sacrificing your target profit.
Price a Bundle →PayPal Fee Calculator UK
Estimate PayPal transaction fees, the amount you receive after fees and how much to charge to reach a target net amount.
Calculate PayPal Fees →Know What Stock Is Worth Before You Buy
Analyse charity shop finds, car boot purchases, clearance deals and multi-buy opportunities.
Charity Shop ROI Calculator
Check whether a charity shop find offers enough projected profit and ROI.
Check a Charity Shop Deal →Car Boot Sale Profit Calculator
Calculate potential resale profit before negotiating on car boot stock.
Check Car Boot Profit →Retail Clearance Calculator
Analyse clearance stock before committing cash to a discounted retail opportunity.
Analyse Clearance Stock →Multi-buy Deal Calculator
Work out the real unit cost and resale potential of multi-buy promotions.
Analyse a Multi-buy →Maximum Buy Price Calculator
Set your walk-away price before sourcing, negotiating or committing to stock.
Calculate Your Limit →Compare Fees Before Choosing Where to Sell
Estimate marketplace costs and analyse your expected profit across the UK’s major platforms.
UK Marketplace Profit Comparison Calculator
Enter one product scenario and compare estimated fees, profit, margin and ROI across eBay, Amazon FBA, Etsy, TikTok Shop, Vinted and Depop.
eBay Fee & Profit Calculator
Estimate eBay fees, net profit, margin and ROI.
Calculate eBay Profit →Amazon FBA Profit Calculator
Estimate referral, FBA and other Amazon selling costs.
Calculate FBA Profit →Etsy Fee & Profit Calculator
Estimate Etsy fees and projected take-home profit.
Calculate Etsy Profit →Vinted Profit Calculator
Work out your expected profit from a Vinted sale.
Calculate Vinted Profit →Depop Fee & Profit Calculator
Estimate Depop payment costs and final profit.
Calculate Depop Profit →TikTok Shop Fee Calculator
Estimate commission and selling costs before listing.
Calculate TikTok Profit →eBay Promoted Listings Calculator
See how advertising costs affect eBay profit.
Check Promotion Cost →Facebook Marketplace Profit & Offer Calculator
Calculate profit, margin, ROI and your minimum acceptable buyer offer.
Calculate Facebook Profit →Shopify Fees & Profit Calculator
Estimate Shopify fees, profit, margin, ROI and monthly store costs.
Calculate Shopify Profit →Protect Profit After the Sale
Compare shipping options and check parcel dimensions before paying for postage.
UK Shipping Cost Comparison Calculator
Compare delivery scenarios and see how postage costs affect your final profit.
Compare Shipping Costs →UK Parcel Size Checker
Check whether your finished parcel fits common carrier size limits before buying postage.
Check Parcel Size →Understand Important UK Seller Thresholds
Get general guidance on important sales, tax and VAT figures relevant to growing UK sellers.
Turn Reselling Activity Into a Measurable Business
Measure inventory performance, cash efficiency, time return and the numbers behind your growth targets.
Stock Turnover Calculator
Measure how efficiently your inventory is moving and estimate how long stock is being held.
Calculate Stock Turnover →Dead Stock Calculator
Assess ageing inventory, cash tied up in stock and whether slow-moving items may need action.
Analyse Dead Stock →Reseller Hourly Earnings Calculator
Compare your reselling profit with the hours spent sourcing, listing, packing and managing sales.
Calculate Hourly Earnings →Inventory Cashflow Planner
Forecast how sales, business costs and stock purchases could affect available cash and inventory value.
Plan Inventory Cashflow →Reseller Goal Planner
Work backwards from a monthly profit target to estimate the sales, revenue and inventory needed to support it.
Build Your Goal Plan →Useful Numbers Start With Clear Assumptions
SellerStack tools are designed to help you test a decision before committing money, changing a price or choosing a selling route.
Free to Use
Use SellerStack calculators and decision tools without a paid SellerStack account.
Built Around Your Inputs
Results depend on the prices, costs, fees and other assumptions you enter into the tool.
Fees & Policies Can Change
Marketplace presets are planning assumptions rather than a live fee feed. Check current fees before important selling or pricing decisions.
UK First
SellerStack is built primarily for UK online sellers, with US support available in selected calculators.
Want a Repeatable Reseller Profit System?
Download the free UK Reseller Profit Toolkit with worksheets, fee cheat sheets, sourcing frameworks and links to SellerStack calculators.