Ecom Almanac is a working reference desk for online sellers: currency and country codes, image sizes, fee math and pre-launch checklists — in tables you can bookmark and trust.
All reference pages are dated and revised on a fixed schedule.
Standard UTC offsets from UTC-12 to UTC+14 with example cities, plus which markets move their clocks for daylight saving and which stay fixed.
Women's and men's size conversion in one place: US, UK and EU numbers next to the actual bust, waist, hip and chest measurements in cm and inches, plus the reason the EU number is never quite the same twice.
All 183 two-letter ISO 639-1 language codes in one table, for hreflang tags, store translations, product feeds and Accept-Language headers.
What GTIN, UPC and EAN actually mean, how many digits each has, which barcode carries them, and where retail POS ends and case logistics begins.
Standard shipping label dimensions in inches and millimeters, the carriers and printers that use each, and why 4 by 6 is the one to buy.
Margin and markup are not the same number. This page explains the difference, gives a conversion table and an interactive calculator you can run with your own cost and price.
A working pre-launch checklist for a new online store: storefront, legal pages, payments, shipping, SEO basics, analytics and the tests to run before you announce anything.
What a store pays per order on each Shopify plan: subscription rates, processing formulas and an interactive calculator you can run with your own numbers.
The official Shopify limits for product photos, video and 3D models in one table: maximum pixels, file sizes and formats, straight from the Shopify Help Center.
The image dimensions a store actually posts in one table: feed posts, Reels, Stories, pins and link previews, checked against each platform's official documentation.
Every active ISO 4217 currency in one table: alphabetic code, numeric code and currency name, for checkout settings, product feeds and payment APIs.