How-to guides for online sellers

Plain-language guides with worked examples and cited sources. Each one links to the Quietcog browser tool that does the job.

Dimloom guides

Dimensional weight and shipping cost estimator. Open Dimloom.

How to measure a parcel and work out its dimensional weight
Measure a packed box, round the sides, divide by the carrier's divisor and compare with actual weight, with a worked example.
USPS Ground Advantage dimensional weight: the 139 divisor and the 1 cubic foot rule
What Domestic Mail Manual 283 says about dimensional weight for Ground Advantage, with worked examples.
UPS and FedEx billable weight: how the rules differ
Divisors and rounding as UPS and FedEx publish them, including where FedEx's own documents disagree.
How to compare carriers for one parcel using your own rates
A spreadsheet method for estimating per-parcel cost on several carriers from rates you were quoted.

SKU generator and barcode label sheet maker. Open Barloom.

UPC and EAN barcodes: what GS1 licensing means for sellers
Why UPC and EAN numbers are licensed, what resale means, and when you do not need them.
How to calculate a UPC or EAN check digit by hand
The GS1 check-digit method with a 13-digit and a 12-digit worked example.
How to design a SKU scheme that survives growth
Practical rules for unique, short, consistent SKUs and how to generate every combination.
How to print barcode labels on a label sheet without drifting or shrinking
Disable scaling, run a plain-paper test, adjust alignment and test-scan before the full run.

Packing slip and pick list maker. Open Sliploom.

How to print packing slips from a Shopify orders CSV
Export orders from Shopify, understand the one-row-per-line-item layout, and get to printed slips.
How to make packing slips from Etsy and eBay order exports
Where to download order files on Etsy and eBay and how to prepare them for packing slips.
How to build a pick list from an orders CSV
Total units per SKU across a batch of orders with a pivot table.
Packing slips: full page, half page or 4 x 6 in?
Compare slip formats and print them at actual size.

Shipping label sheet layout tool. Open Labelloom.

How to fit two shipping labels on one sheet of paper
Place two labels on one sheet at 100% scale, with a test print and scan.
Thermal 4 x 6 in or Letter paper: choosing how to print shipping labels
What USPS, UPS and FedEx say about printers and stock, and the trade-offs of each format.
How to print a shipping label at actual size and test-scan it
Turn off scaling, measure a test print, check margins and scan before relying on a setup.
Why a shipping label won't scan, and how to fix it
A symptom-cause-fix table based on FedEx's printer guide and USPS label help.

Spreadsheet column mapper for marketplace uploads. Open Listloom.

How to create eBay listings in bulk from a spreadsheet
Get the template in Seller Hub Reports, fill it, upload it and read the report.
How to fill an Amazon inventory file template from your own spreadsheet
The template workflow from Amazon's public guide, with Check Your File and a small first test.
What you can and cannot do in bulk on Etsy
Etsy has no bulk upload of new listings; here are bulk edit, copy listing and CSV downloads.
How to stop a CSV file from running formulas when you open it
What CSV injection is, how to check for it, and the limits of the common fixes.