A family spending $800 a month at the supermarket is doing roughly $9,600 a year on groceries. That sounds high until you realize it works out to about $200 a week — well within range for a household of three or four eating mostly at home.
The instinct is to grab the highest grocery rate, but the highest rate is only useful inside its cap. Two of the cards that dominate this category — Blue Cash Preferred and Amex Gold — both impose annual grocery caps. One of them stops earning the bonus rate before $9,600 a year. The other doesn't.
Key insight
Blue Cash Preferred earns 6% at supermarkets — but only on the first $6,000 per year. Past $6k it drops to 1%. At $9,600/yr in groceries, $3,600 of your spend earns just 1% on BCP. Amex Gold caps at $25,000/yr, so all $9,600 earns 4x (~8% effective at typical point valuations). Once you cross roughly $500/mo in groceries, the Gold pulls ahead — and it widens the lead the more you spend.