DigitalQuiver Tools

Free Amazon Seller Tools

25 free calculators for Amazon FBA sellers and KDP publishers — profit & ROI, PPC metrics, royalties, spine width and more. Everything runs in your browser, nothing is uploaded.

FBA Profit & ROI CalculatorWork out your real profit, margin and ROI on any Amazon FBA product. FBA Dimensional Weight CalculatorCalculate dimensional weight from package dimensions using Amazon's divisor. PPC ACOS/ROAS CalculatorCalculate ACOS, ROAS and your break-even ad spend for Amazon PPC. Profit Margin CalculatorCalculate profit, margin % and markup % from cost and selling price. KDP Royalty CalculatorEstimate your Kindle eBook, paperback or hardcover royalty using Amazon's published formulas. KDP Spine Width CalculatorCalculate paperback spine width from page count and paper type. Amazon Title/Bullet Character CounterLive character counts for your Amazon listing title and bullet points. ASIN ExtractorExtract ASINs from any Amazon product URL, one per line. UPC/EAN Barcode Check Digit ValidatorValidate or calculate the check digit for UPC-A and EAN-13 barcodes. Book Description HTML FormatterFormat bold, italic, headings and lists into HTML your KDP book description accepts. Amazon Referral Fee CalculatorCalculate Amazon's referral fee and your net proceeds from price and fee %. KENP Royalty CalculatorEstimate your KDP Select Global Fund royalty from pages read and this month's rate. ISBN/EAN-13 Barcode GeneratorGenerate a scannable EAN-13 barcode SVG from an ISBN or 12/13-digit code. KDP Bleed, Margin & Gutter CalculatorCalculate your KDP interior page size, gutter and margins from trim size and page count. Amazon Backend Search Term Byte CounterCount your backend keywords against Amazon's 250-byte limit before you save. FBA vs FBM Cost ComparisonCompare per-unit profit between Fulfilled by Amazon and Fulfilled by Merchant. Break-Even Selling Price CalculatorWork backward from your target profit to find the price you need to charge. Inventory Reorder Point CalculatorKnow exactly when to reorder stock before you run out. FBA Prep & Labeling Cost CalculatorAdd up every prep cost per unit to find your true landed cost. Multi-Pack / Bundle Profit CalculatorSee whether bundling units into a multi-pack actually improves your per-unit profit. Amazon Referral Fee Category LookupLook up Amazon's referral fee percentage for common product categories. KDP Full Cover Wrap Size CalculatorCalculate the exact full-wrap cover dimensions for your paperback, including bleed and spine. Low-Content Interior Page GeneratorGenerate lined, graph or dot-grid interior pages as a ready-to-upload PDF. Merch by Amazon Design Spec CheckerCheck your design PNG against Amazon Merch's size, format and transparency rules. Merch by Amazon Print Area PreviewSee roughly how your design will sit within the printable area on a shirt.

Guides & Explainers