Negative keywords are the highest leverage, lowest risk lever in a search account. They cost nothing, they protect budget immediately, and they compound. Yet most accounts have a thin, stale list. Here's how to fix that without accidentally blocking good traffic.
What a negative keyword actually does
A negative keyword stops your ad from showing on searches that contain it. Add "free" as a negative and you stop paying for "free quote", "free trial", "free download", searches that rarely convert for most businesses.
Match types, in plain English
- Negative exact, blocks only that exact search. The safest, most surgical option.
- Negative phrase, blocks any search containing that phrase in order.
- Negative broad, blocks searches containing all the words, in any order. The widest, and the easiest to over block with.
The rule of thumb: start on exact, widen deliberately. Exact blocks the one search you've seen waste money. Only move to phrase or broad when you're sure the variations are all bad too.
Where to find them: the search terms report
The search terms report is the source of truth. Sort by cost, scan for terms with spend and no conversions, and ask a simple question of each: "Would I ever want to pay for this?" If the answer is no, it's a negative.
Negative keyword lists and shared lists
Some negatives are universal, competitor brands you don't want, "jobs", "salary", "free". Put those in a shared negative list and apply it across campaigns so you maintain them once, not ten times. Keep campaign specific negatives at the campaign level.
The one mistake to avoid
Over blocking. A too-aggressive broad negative can silently suppress good traffic, and because nothing "breaks", you may not notice for weeks. Widen slowly, and when in doubt, stay on exact.