Consistent unit prices on every online grocery listing
Shows one comparable price per ounce, pound or count on grocery sites, so pack sizes compare at a glance.
- Browser extension
- Data & Analytics
- Medium build
- 4-6 weekends
- Researched by ProjPilot
The problem
Online grocery sites show unit prices inconsistently: per ounce on one item, per count on the next, and sometimes not at all. Shoppers comparing a 12-pack with a 30-pack end up doing math on a phone calculator. The few unit-price extensions that exist are small and mostly cover Amazon and Walmart.
For: Budget-conscious households · Online grocery shoppers · Bulk buyers
Why now
NIST says no federal rule requires unit pricing, and its model e-commerce regulation makes online unit prices optional for standard packages. The BLS food-at-home price index stood at 321.5 in August 2026, up from 243.1 in January 2020.
Demand signals
Monthly Google searches in the US, pulled 2026-09-24. These are the words people with this problem actually type.
What exists already
- Amazon Unit Price ↗Free, Amazon only (about 1,000 users); links in its popup carry the developer's affiliate tag.
- Unit Price Shopper ↗Sorts Amazon, Walmart and Albertsons-brand results by unit price; small (264 users), with an affiliate tag.
- Unit-price (Walmart) ↗Sorts walmart.com results by unit price; Walmart only.
- Sort by unit price for Amazon & Walmart ↗Re-sorts results by cost per unit on two stores; very new, with 21 users.
MVP scope
- Read size and price from listings on major grocery sites
- Normalize to one unit per category (per oz, per lb, per count, per sheet)
- Badge the cheapest per-unit option in search results
- Handle multipacks such as 6 x 12 oz
- User-reported fixes for odd listings
- No login and no affiliate links; parsing happens in the browser
How it could make money
- Free core extension
- Supporter plan $1.99/month for price-drop alerts on saved items
Suggested stack
- Chrome MV3 + Safari Web Extension
- TypeScript
- Per-site parsers with fixture tests
Sources
- NIST SP 1181-2025, Unit Pricing Guide: A Best Practice Approach to Unit Pricing (accessed 2026-09-24)
- NIST Handbook 130 (2026), Section IV.G Uniform E-commerce Regulation (accessed 2026-09-24)
- BLS Public Data API: CPI-U food at home, U.S. city average (series CUUR0000SAF11) (accessed 2026-09-24)
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