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Grout pen vs grout paint

Updated: 21 October 2026

A marker, a brush-on colourant and a bag of new grout all claim to sort stained grout. Use a pen when the joint is sound, glazed and small. Use a colourant when the area is large and you will follow that system’s wait. Regrout when the joint has failed. The twelve pens in the [Grout pen](/hub/flooring-tools-and-accessories/grout-pen) comparison, captured on amazon.co.uk on 19 October 2026, cost about £4.90 to £12.60. They are the marker side of this page. Drawing steps are on [how to use a grout pen](/hub/flooring-tools-and-accessories/grout-pen/sub/grout-pen-how-to-use). Peter F. scored these listings, not a lab, and amazon.co.uk links may earn a commission.

A marker, a brush-on colourant and a bag of new grout all claim to sort stained grout. Use a pen when the joint is sound, glazed and small. Use a colourant when the area is large and you will follow that system’s wait.

Our top picks

UniBond UniBond grout reviver pen, white, pack of 3

Best overall

UniBond UniBond grout reviver pen, white, pack of 3
8.7/10about £12.60
View offer
QHSXMQ QHSXMQ white grout pen, 8 with spare nibs

Best value

QHSXMQ QHSXMQ white grout pen, 8 with spare nibs
8.7/10about £5.99
View offer
Flintronic Flintronic light grey grout pen, 10 pack

Alternative

Flintronic Flintronic light grey grout pen, 10 pack
8.1/10about £8.98
View offer
On this page
  1. 1.Three different jobs
  2. 2.When the pen is enough
  3. 3.When paint or colourant fits better
  4. 4.When you should regrout

Three different jobs

A grout pen coats the joint that is already there. Ideal Home treats that as a touch-up. A grout paint, as sellers such as Smartseal use the word, is a brush-on sealer-colourant, after a primer. New grout is a fill, and the only one of the three that replaces missing material. If it draws from a nib, it is a pen. If you brush it from a pot, it is a colourant. Sound and small leads to a pen. Sound and large leads to a colourant. Failed leads to a regrout.

When the pen is enough

A pen is enough for a short run of sound grout on glazed wall tile: a splashback, a basin, or a dry, firm shower wall. The documented white option is UniBond at about £12.60, 4.1 from 20,843 reviews. The cheaper white option with spare nibs is QHSXMQ at about £5.99, and that listing does not mark the pens as waterproof. Who each is for is the best grout pen page. A whole floor is a long job with a marker that may only flow pointing downhill. Shower floors usually are not a pen job. That case is the grout pen shower page.
UniBond UniBond grout reviver pen, white, pack of 3

Testsieger

UniBond UniBond grout reviver pen, white, pack of 3
8.7/10about £12.60
View offer

When paint or colourant fits better

A brush-on colourant fits when the grout is sound and the area is too big for a nib: a kitchen floor, a hallway, or a tray you accept will still be a coating. Smartseal says a primer is part of the system and that the colourant lasts longer than cheap pens. That is the seller’s claim, not a wear test. The B&Q listing prints up to 15 years beside a 6-month guarantee, a 48-hour wait before water, and a warning against stone and unglazed tile. A snippet showed £36.95 for a 237 ml kit.

When you should regrout

Regrout when the joint has failed. Powder, gaps you can see into, tiles that shift, or water in the room below are the signs. Bromley Tilers say crumbling grout needs raking out. A coating on loose grout comes off with it. Silicone at the tray is cut out and resealed, not drawn over. Firm and stained means pen or colourant, by the size of the area. Soft and hollow means the £4.90 twelve-pack will not help.

Common questions

Is a grout pen the same as grout paint?
No. A grout pen is a marker that coats a narrow joint from a nib. Grout paint, in UK product listings, usually means a brush-on colourant or sealer-colourant from a bottle, sometimes with a primer. New grout in a bag is a third product that fills a joint you have raked out. Sellers sometimes use “paint” in the title of a pen. Judge the tool by how you apply it.
Which lasts longer?
Nobody has a shared UK lab test of the pens in this set against a brush-on kit. Smartseal claims its colourant lasts longer than cheap pens and has printed up to 15 years on a B&Q listing, beside a 6-month guarantee. Treat the 15 years as the seller’s claim. UniBond calls its own pen a mid-term cover. On a floor you walk on, both coatings can wear in patches. Failed grout outlasts neither, because both sit on material that is already loose.
When is a pen the right tool?
Use a pen for a small, sound, glazed joint: a splashback, a basin, or a short run of shower wall after the grout is clean and dry. In this set that is a spend of about £4.90 to £12.60, with UniBond the documented white pen and a spare-nib multipack the cheaper white route. A nib that is too wide stains the tile, so the joint still has to be wide enough for the tip you bought.
When is a brush-on colourant the better job?
Use it when the grout is sound and the area is a whole floor or a long run of joints, and you will follow that brand’s prep, including a primer if it asks for one. The B&Q Smartseal page also says to wait 48 hours before water and to keep it off unglazed and natural stone. It is the better job for scale. It is a poor swap for a ten-minute touch-up, and it is still the wrong job if the joint has crumbled.
Can I change white grout to grey with a pen?
Yes, if you buy a grey pen and the joint is sound. Sinofort at about £4.90 and Flintronic at about £8.98 are the light-grey packs in this set. The colour will sit on the surface, so a chip later shows the old white underneath. Test a corner in daylight, because Sinofort’s bullets mix the word white into a grey listing and Flintronic’s colour codes do not match each other. A pen will not turn a missing joint grey. There is nothing there to colour.
Will either product fill a missing joint?
No. A pen and a brush-on colourant coat the joint that remains. They bridge a hairline stain, not a gap you can see into. Filling that gap is new grout after you have raked the joint out. Using paint to hide a hole leaves a skin that cracks as soon as the edge is wet or walked on. If you can fit a fingernail into the joint, you are past both coatings.

Related pages

Grout pen buying guide

Grout pen

Best grout pen: UniBond three-pack or white spare nibs

How to use a grout pen on clean, dry bathroom joints

Grout pen shower: glazed walls, not the tray floor

Sources

Public UK sources used for this comparison. Listing prices, stars and review counts are the amazon.co.uk figures saved for these 12 ASINs on 19 October 2026.

  1. UniBond Triple Protection Grout Reviver Pen (retrieved 19 October 2026)
  2. UniBond label details via McGrocer (retrieved 19 October 2026)
  3. ASDA: UniBond grout reviver pen 7 ml (retrieved 19 October 2026)
  4. Consumer Rights Act 2015, section 9 (retrieved 19 October 2026)
  5. HSE: Treated articles (retrieved 19 October 2026)
  6. Bromley Tilers: How to clean grout (retrieved 19 October 2026)
  7. Homebuilding: Cleaning grout (retrieved 19 October 2026)
  8. Ideal Home: Grout colouring with a grout pen (retrieved 19 October 2026)