Android users get the short end of the tax-app stick. Most polished tools launch iOS first, and the Play Store fills with ad-stuffed clones. Judge ruthlessly. - Data first: year-effective dates, rate types, a named source. If it will not say where its numbers come from, treat every number as a rumor. - Check the last update date before installing. A tax reference app untouched since a rate reform gives you confident wrong numbers. Worse than no app. - Offline mode and share-to-accountant: the table in airplane mode, exportable in one tap. - Permissions: a reference app asking for your contacts is a billboard-sized red flag. - Free with no ads and no premium tier usually means you are the product. Just pay the three dollars only. The app is the easy part. The maintained table behind it is the product. Ours is free, and IncorpTrack handles the actual UK or Singapore registration for $49 plus the government fee.