Butter is one of the more forgiving things in your fridge — its high fat and (in salted versions) salt content make it last far longer than most dairy. The short answer: salted butter keeps several weeks to a couple of months in the fridge, unsalted around 2-3 weeks, and either freezes for up to about a year. It also handles being left out better than people expect. Here's the full picture, including how to spot when it's finally turned.
- Salted butter (fridge): several weeks to ~2 months.
- Unsalted butter (fridge): about 2-3 weeks — salt is a preservative.
- Frozen: up to ~1 year with little quality loss.
- Gone bad: rancid, sour or "old oil" smell — bin it.
How long butter keeps
Butter's shelf life depends mainly on salt, which slows the spoilage that affects all dairy fat. Kept wrapped and cold in the fridge at 0-5°C (UK FSA), here's roughly what to expect:
Butter almost always carries a best-before date rather than use-by, which means it's about quality — well-kept butter is usually fine for a while past it, judged by smell and taste.
Can you leave butter out?
Yes, within reason — and it's why so many people keep a butter dish on the counter for spreadable toast. Salted butter tolerates a few days at cool room temperature in a covered dish, because the salt and low water content discourage bacteria. Unsalted and whipped butter are better kept in the fridge. Either way, keep it covered (light and air cause rancidity), out of warm or sunny spots, and only leave out what you'll use within a few days.
Freezing butter
Butter is one of the best freezer candidates there is — it freezes for up to about a year with almost no change in texture or flavour. Keep it in its original wrapper or an airtight bag, freeze it before the date, and thaw it in the fridge overnight. It's ideal for stocking up when butter's on offer. See can you freeze butter for the details.
How to tell if butter has gone bad
Butter doesn't usually pose the bacterial risk that fresh dairy does, but it does go rancid — and rancid butter tastes genuinely unpleasant:
- Smell: sour, cheesy or like old cooking oil — the clearest sign.
- Taste: sharp, bitter or "off" rather than clean and creamy.
- Sight: a darkened, waxy or discoloured surface, or any mould.
If it smells and tastes clean, it's good to use. If it's rancid, throw it out — it won't harm you the way spoiled meat would, but it'll ruin whatever you cook with it.
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Butter rarely gets wasted on its own — it lasts too long — but it's a good reminder that different foods need wildly different timelines, which is exactly what a tracker keeps straight for you. For the full set, see how long food lasts in the fridge and how long cheese lasts.
Frequently Asked Questions
How long does butter last in the fridge?
Salted butter keeps several weeks to a couple of months in the fridge, while unsalted butter is best used within about 2-3 weeks because salt acts as a preservative. Both last well to and often past their best-before date if kept cold and wrapped. For longer storage, butter freezes for up to about a year.
Can you leave butter out of the fridge?
Salted butter can be left at cool room temperature for a few days in a covered dish, since salt slows spoilage — handy for spreadable butter. Unsalted and whipped butter are better kept refrigerated. Either way, keep it covered and out of warm or sunny spots, and don't leave large amounts out for long.
Can you freeze butter?
Yes. Butter freezes very well for up to about a year with little change in quality. Keep it in its wrapper or an airtight bag, freeze it before the date, and thaw it in the fridge. It's an easy way to stock up when butter is on offer without any going to waste.
How can you tell if butter has gone bad?
Rancid butter smells sour, cheesy or like old oil, and may taste sharp or bitter. The surface can darken or turn yellow and waxy. Butter doesn't usually grow dangerous bacteria, but rancid butter tastes unpleasant and should be thrown out. If it smells and tastes clean, it's fine.