How Long Does Paint Last Opened Or Unopened?
Leftover tins are handy for touch-ups if you store them well and know the signs that paint has gone off.
The short answer
Dulux says leftover paint should last up to two years when the lid is sealed tightly and the tin is kept away from direct sunlight somewhere frost-free. Sealed tins keep for longer, and many brands print a batch or best-before date on the lid or base. Paint that smells foul, has gone lumpy or has mould on it should be thrown away.
Paint isn't cheap, and most decorating jobs finish with a good amount left in the tin. Throwing it out feels wasteful, and a well-kept tin is worth having for touch-ups or a smaller job later.
We get through a lot of paint across our homes, rentals and Airbnbs, so our store of leftover tins is never small. This guide covers how long paint lasts, how to tell when it's gone off and the way we store it so it stays usable.
Signs Your Paint Has Gone Off
Paint does expire eventually, but it lasts longer than most people expect when it's stored properly. How long yours keeps comes down to whether the tin has been opened, what type of paint it is and how good it was to start with. Before using an old tin, check for these signs:
- A sour, rotten or rancid smell
- A thick, lumpy texture that won't stir smooth
- Mould growing on the surface or under the lid
- A change in colour from what's on the label
- Separation that doesn't mix back together
The smell is the clearest giveaway. Paint that has turned smells foul as soon as the lid comes off, and if you put it on a wall, that smell lingers in the room. Get rid of it rather than taking the risk.
Oil-Based And Water-Based Paint Shelf Life
The type of paint changes how long it keeps. Water-based paints such as emulsion and most modern satinwoods behave differently in the tin from oil-based paints like traditional gloss, so follow the guidance printed on each tin.
Oil-based paint forms a skin on top once opened, which you'll need to cut out and discard before stirring. Water-based paint doesn't skin in the same way, but it's ruined by frost, so where you keep it matters even more.
How Long Does Paint Last?
Once The Tin Is Opened
Dulux says leftover paint should last up to two years if it's stored correctly, away from direct sunlight and somewhere frost-free. That only holds if the lid goes back on tightly. Leave a tin half-open in a freezing shed and the paint can be ruined.
If The Tin Is Still Sealed
A sealed tin keeps for longer than an opened one. Many brands print a best-before or batch date on the lid or the base of the tin, so check there first, and follow what the tin says for that specific product.
Storing Leftover Paint So It Lasts
Good storage is what gets paint to the top end of those figures. These are the habits we stick to:
- Seal The Lid Properly: wipe the rim clean and tap the lid down firmly all the way round so no air gets in.
- Pick A Cool, Dry Spot: keep paint indoors somewhere well ventilated with a steady temperature, rather than a damp garage, shed or cellar.
- Keep It Out Of Sunlight: direct sun warms the tin and can affect the paint's quality and colour.
- Protect It From Frost: frozen water-based paint is unusable, so bring any tins kept outside indoors before cold spells.
- Avoid Heat Sources: radiators, boilers and other heat sources spoil paint just as badly as the cold.
- Label Every Tin: write the colour, the room it was used in and the date on the lid so you know what to use first.
Good brushes are worth keeping with the paint. Clean them thoroughly, reshape the bristles and store them hanging upright or in a brush holder. Our pick of the best paint brushes for decorating covers ones that last for years with that care.
With paint rollers and sleeves, we keep the frame and replace the sleeve after each job. The frame is where most of the cost is, and sleeves are cheap to replace.
Separated Paint Isn't Always Ruined
Over time, the pigments, binders and solvents in paint settle into separate layers. Opening a tin to find liquid sitting on top doesn't mean the paint is off, as long as it mixes back to its original consistency.
How We Rescued A Separated Emulsion
If the tin has been stored well and smells normal, give it a try. The photos below show an emulsion paint of ours that had separated badly. We stirred it thoroughly until it was smooth again, then used it for touch-ups, and the colour matched the original paintwork.
Stir right down to the bottom of the tin. Separated paint that hasn't been fully remixed goes on with uneven colour and streaks, covers poorly and doesn't grip the surface as it should.
Getting Rid Of Paint You Can't Use
Never pour old paint down the sink or a drain. Take it to your local household waste recycling centre instead, as most have an area set aside for paint. Check your council's rules before you go, since some only take it once it's dried out.
Before you dispose of it, think about whether it's worth keeping. Half a tin of gloss paint for woodwork is ideal for touching up scuffs on skirting and doors. Usable paint you don't need can go to a local community group or a neighbourhood swap page.
Chalk paint and other specialist finishes have a shorter shelf life than standard emulsion once opened, so check the guidance on the tin and use them up sooner.
Quick Questions And Answers
Can you use paint that has been frozen?
Water-based paint that has frozen and thawed is ruined if it stays lumpy or stringy after a thorough stir, so throw it away. If it stirs back to a smooth consistency with no lumps, test it on a scrap of board before using it on a wall. To avoid the problem, keep paint indoors and away from unheated sheds and garages through winter.
Does paint have a use-by date on the tin?
Many paint brands print a best-before or batch date on the lid or the base of the tin, which shows how long the unopened paint should keep. Once opened, how well you store it matters more than the printed date. Write the date you opened it and the room it was used in on the lid so you know its age later.
Why does old paint smell bad?
Old paint smells bad when bacteria have grown in it, which happens when air or contamination gets into a tin that wasn't sealed properly or was stored somewhere warm. A sour or rotten smell means the paint has gone off and should be thrown away, as the smell carries over onto walls and ceilings once it's applied.
How do you store leftover paint for touch-ups?
Store leftover paint for touch-ups in its original tin with the rim wiped clean and the lid tapped down firmly, kept indoors somewhere cool, dry and frost-free. Label it with the colour, the room and the date. For small amounts, decanting into a smaller airtight container reduces the air in the tin and helps it keep longer.
Is separated paint ruined?
No, separated paint isn't ruined as long as it mixes back to its original consistency and smells normal. We had an emulsion that had separated badly, stirred it thoroughly until it was smooth and used it for touch-ups, and the colour matched the original paintwork. Stir right down to the bottom of the tin, or it goes on streaky.
Which lasts longer in the tin, water-based or oil-based paint?
Water-based paint tends to keep better in the tin than oil-based paint, though the tin's own guidance for that product is the best guide. Oil-based paint forms a skin once opened, which you cut out and discard. Water-based paint doesn't skin, but frost ruins it, so where you keep it matters.
What's the right way to get rid of paint I can't use?
Never pour old paint down the sink or a drain. Take it to your local household waste recycling centre, where most have an area set aside for paint, and check your council's rules first, as some only take it once it's dried out. Usable paint you don't need can go to a local community group or neighbourhood swap page.
Is it worth keeping half a tin of gloss?
Yes, half a tin of gloss for woodwork is ideal for touching up scuffs on skirting and doors. Seal the lid properly, keep the tin somewhere cool, dry and frost-free, and write the colour, the room and the date on the lid so you know what to use first.
Eddie spent five years as a self-employed painter and decorator before going part time to become one of the main writers at DIY Works. From garden fences to mist coats on fresh plaster, painting and decorating is his speciality.