What is the best caulk for re-sealing a bathtub?

Best choice: 100% silicone kitchen-and-bath caulk. It stays flexible, waterproof, and resists mold/mildew—better suited to a bathtub than ordinary acrylic caulk.Laticrete+1

• GE Advanced Silicone 2 Kitchen & Bath - $11.48 (The Home Depot)

I’d use GE Advanced Silicone 2 or DAP Silicone Max. Remove all old caulk, clean/dry the joint thoroughly, apply a continuous bead, and keep the tub dry for the manufacturer’s specified cure time.nationalhardwaregroup.com

For re-sealing a bathtub, the short answer is that 100% waterproof silicone caulk is the gold standard for durability, flexibility, and mold resistance.[1]

The top options on the market depend slightly on your project needs:

Best Overall: Gorilla Waterproof Silicone Caulk & Seal – Excellent for high-moisture areas, shrinks/crack-proof, and safe for water exposure in just 30 minutes.

Best Quick-Drying / Heavy Duty: GE Supreme Silicone Kitchen & Bath Sealant – Highly flexible, features lifetime mold-free protection, and won't shrink or crack.

Best Beginner-Friendly / Easy Cleanup: DAP Kwik Seal Plus – A siliconized latex/acrylic blend. While not as long-lasting as 100% silicone, it applies smoothly, tools easily, and cleans up with water.bobvila.com+1[2]

Key Tips Before You Start:

1. Strip the old caulk completely and scrub the joint with rubbing alcohol or white vinegar to kill any hidden mold or soap scum.
2. Ensure the surface is 100% dry before applying new silicone (give it at least 24 hours of no use after cleaning).
3. Fill the tub with water before you caulk if it's an acrylic or fiberglass tub. This weighs the tub down so the joint is stretched before the caulk cures, preventing it from tearing when you fill the tub later.

If you'd like, let me know:

• What material is your tub (acrylic, fiberglass, cast iron)?
• Do you prefer a squeeze tube or a caulking gun cartridge?

I can give you a step-by-step application guide tailored to your setup.

For re-sealing a bathtub, 100% silicone kitchen-and-bath caulk is the best choice. It stays flexible, is waterproof, and resists cracking and mildew—better suited to a constantly wet tub edge than ordinary acrylic/latex caulk.LATICRETE+1

My top picks

• GE Advanced Silicone 2 Kitchen & Bath - $11.48 (The Home Depot)

• Gorilla Waterproof 100% Silicone - $9.84 (The Home Depot)

• DAP Silicone Max Kitchen & Bath - $12.48 (The Home Depot)

• Best overall: GE Advanced Silicone 2 Kitchen & Bath — 100% silicone, permanently flexible, waterproof, and mold-resistant. It's a particularly good choice for a tub-to-tile joint. GE lists it as water-ready in 30 minutes, though I'd personally wait 24 hours before using the tub for a safer cure.GE Sealants

• Excellent alternative: Gorilla 100% Silicone — also waterproof, mildew-resistant, and water-ready in 30 minutes.Bob Vila

• Good value: DAP Silicone Max — 100% silicone and specifically designed for kitchen/bath applications.

One important tip

Remove all the old caulk first. Don't caulk over it. Scrape/cut the old bead away, clean the surfaces thoroughly, and let the joint dry completely before applying the new silicone. The preparation is arguably more important than which premium silicone you choose.National Hardware Group

If you tell me what your tub is made of (fiberglass, acrylic, porcelain, etc.) and whether the surrounding wall is tile, I can tell you exactly which product/color I'd use and how to apply it for a clean professional-looking bead.

For re-sealing a bathtub, I’d choose 100% silicone kitchen-and-bath sealant. It stays flexible, is waterproof, and is much better suited to a constantly wet tub joint than ordinary acrylic/latex caulk.Oatey+1

• GE Supreme Silicone Kitchen & Bath Sealant - $13.48 (The Home Depot)

My top picks

• Best overall: GE Supreme Silicone Kitchen & Bath — 100% silicone, waterproof, permanently flexible, and designed specifically for tubs/showers. It's also water-ready in about 30 minutes, although I'd still follow the label's full-cure instructions before using the tub.Bob Vila

• Excellent alternative: DAP Silicone Max — also 100% silicone, with 20-year mold/mildew resistance and 30-minute water readiness.Catest

• Good value: GE Advanced Silicone 2 — another 100% silicone option specifically intended for kitchen/bath applications.GE Sealants

• GE Supreme Silicone Kitchen & Bath - $13.48 (The Home Depot)

• DAP Silicone Max Kitchen & Bath - $12.48 (The Home Depot)

• GE Advanced Silicone 2 Kitchen & Bath - $11.48 (The Home Depot)

One important tip: remove all of the old caulk before applying the new bead. Clean and dry the joint thoroughly, then apply the silicone in one continuous bead and tool it promptly. Don't caulk over existing silicone—it usually won't bond reliably.

If you tell me whether your tub is fiberglass, acrylic, porcelain/enamel, or tile, I can recommend the exact caulk and the best way to apply it so it doesn't peel or mold.

For re-sealing a bathtub, 100% silicone caulk is universally considered the best choice because it is permanently waterproof, highly flexible (allowing it to handle slight shifts in the tub as it fills with water), and resistant to cracking or shrinking.bobvila.com+1

Top-performing options depend on your specific priorities:

• Best Overall / Most Durable: GE Supreme Silicone Kitchen & Bath Sealant . It offers incredible flexibility, strong adhesion, and a 30-minute water-ready formula with built-in mold resistance.bobvila.com+1
• Best Alternative Silicone: [Gorilla Waterproof Silicone Caulk & Seal ](https://www.bobvila.com/articles/best-caulk-for-shower-or-bathtub/) . Highly praised for its shrink-proof, crack-proof, and fast-curing performance in high-moisture environments.bobvila.com+1
• Easiest to Use & Clean Up (Beginner Friendly): DAP Kwik Seal Plus (Siliconized Acrylic Latex). While pure silicone lasts longer, Kwik Seal Plus goes on smoother, cleans up easily with a wet rag, and features Microban antimicrobial protection . It is great if you are a beginner, though it doesn't flex or last quite as long as 100% silicone.bobvila.com+2

Quick Tips for Success

1. Strip the old caulk completely: Use a caulk removal tool and clean the joint with rubbing alcohol. Any mold or leftover residue will prevent the new caulk from sealing.
2. Fill the tub with water before you caulk: Fill the bathtub before applying the bead and keep it filled until the caulk cures. This weights the tub down and stretches the joint so the caulk doesn't tear when you step into a full bath later.
3. Check drying times: Don't expose it to water until the manufacturer's recommended cure time has passed (ranging from 30 minutes to 24 hours depending on the formula).bobvila.com+1

If you'd like, let me know:

• Is your tub made of fiberglass, acrylic, or porcelain?
• Are you looking for clear or white caulk?

I can give you more tailored application tips for your specific setup.

For re-sealing a bathtub, 100% sanitary silicone is the best choice. It stays flexible, is fully waterproof, and is formulated to resist mould and mildew—better suited to a constantly wet, moving joint than ordinary acrylic caulk.LATICRETE+1

My picks

• Everbuild 500 Bath Sanitary Silicone - £5.99 (Toolstation + others)

• Dowsil 785+ Silicone Sealant - £8.60 (Wickes + others)

• No Nonsense 830 Anti Mould Neutral Sanitary Silicone - £8.99 (Screwfix.com + others)

• Soudal Bathroom & Shower Silicone - £6.99 (Screwfix.com + others)

• Best overall: Everbuild 500 Bath Sanitary Silicone — a good UK-specific choice for baths and showers.

• Premium/pro choice: Dowsil 785+ — excellent sanitary silicone and widely used for bathroom work.

• Good budget option: No Nonsense 830 Anti Mould Neutral Sanitary Silicone.

• If you want a very straightforward bathroom product: Soudal Bathroom & Shower Silicone.

Important: Don't just apply new silicone over the old bead. Remove all the old sealant, clean off residue, and let the joint become completely dry before applying the new bead.LATICRETE

If the bath is acrylic, there's also a useful trick: fill the bath with water before applying the silicone so the bath is sitting at its normal loaded position. Let the silicone cure according to the manufacturer's instructions before draining it. This can help prevent the new joint being stretched when the bath is subsequently used.

If you tell me whether your bath is acrylic, steel/enamel, or fibreglass, I can recommend the exact product and colour I'd use.