Cost Rise Margin Alert and Reprice List for Shops

Cost Rise Margin Alert and Reprice List is an offline app (one HTML file in a zip) for the selling side of a shop. You list your items with their shelf price, then log each new cost a supplier gives you. The app keeps the cost history, works out the margin at today's cost and shelf price, compares it with your target, and suggests the price that restores the target margin, rounded up to the step you choose.

The problem it removes: A supplier raises a cost by a few percent, the invoice is paid, and the shelf price stays the same for months. Nobody notices that the margin on a fast item has fallen below target or turned into a loss, because costs live in invoices and prices live on shelf tags. This app puts both side by side and tells you which tags to change, and what the missed margin is each month.

What is inside:

• Items with supplier, shelf price, monthly units sold and an optional target margin per item
• Cost history per item: each new cost with its date, the previous cost, the change in percent and the extra cost per month
• Margin at today's cost and shelf price, with VAT treated the way you set it (shelf prices with or without VAT)
• Alerts page: items below target, items selling below cost, recent cost rises and the margin missed each month
• One tap to log the suggested new price for every item below target, with Undo, and a printable shelf price change sheet
• Reprice log that keeps every old and new shelf price with its date
• Example data you can load in one click, a Start here guide and an Honest limits panel
• JSON backup and restore, CSV export, and CSV import with a check of every row before anything is added

Who it is for: mini-markets, household and electronics shops, gift and fashion sellers and any shop that sets its own shelf prices and gets new costs from suppliers by invoice, message or phone call.

What it is NOT: It does not read supplier invoices, compare suppliers (it is about your selling price, not about finding a cheaper supplier) or change prices in any till or stock system. It does not know your competitors' prices. Targets, VAT treatment and rounding are settings you enter, and nothing here is accounting or tax advice. It is not legal, tax or accounting advice, it is not connected to any government system, bank or messaging service, and it does not file or send anything by itself. UAE e-invoicing is not part of it.

Your data stays on this device in your browser. Back it up with Export; clearing browser data loses it otherwise.

Verified by us: scripted tests in Chromium (109 checks through the real screens: adding, editing and deleting records in every table, required-field messages, backup then clear then restore, CSV export then import, keyboard order, print layouts rendered to PDF, no horizontal scrolling at 375 and 1280 pixels, no network requests) and an independent recalculation by a separately written Python evaluator of 2197 calculated values (25 randomised rows plus the example data) with 0 mismatches. Not tested: Safari and Firefox beyond what is stated here, and no real printer was used (print layouts were checked as PDF).