How Thick Should a Bedliner Be? Mils, Texture and Where to Build Extra
Ask three applicators how thick they spray a bedliner and you may get three answers: "an eighth of an inch," "about 125 mils," "3 millimeters." They might all mean roughly the same thing. Thickness is the single biggest lever on how long a liner survives hard use, and also one of the easiest things to fudge. This guide explains the units, typical builds, where extra thickness pays off, how texture fits in, and how to verify what you paid for.
Key takeaways
- A mil is a thousandth of an inch (25.4 microns). 125 mils is 1/8 inch, about 3.2 mm.
- Bedliners are commonly applied at about 125–250 mils. Build extra on the floor, wheel-well tops and tailgate, where damage concentrates.
- The thinnest spot matters more than the average. Corners and edges are where thin film hides.
- Texture peaks aren't protective thickness. Ask what the base film thickness is.
Thickness units, decoded
Coatings in the US are measured in mils, thousandths of an inch. Outside the US, and on many data sheets, you'll see millimeters or microns. Here's a quick reference:
| Mils | Inches | Approx. fraction | Millimeters |
|---|---|---|---|
| 40 | 0.040 | about 1/25 | 1.0 |
| 62.5 | 0.0625 | 1/16 | 1.6 |
| 100 | 0.100 | about 3/32 | 2.5 |
| 125 | 0.125 | 1/8 | 3.2 |
| 187.5 | 0.1875 | 3/16 | 4.8 |
| 250 | 0.250 | 1/4 | 6.4 |
Coating-gauge manufacturer DeFelsko notes that bedliners are commonly applied between 3–6 mm (125–250 mils). That's far thicker than automotive paint, which is measured in single-digit mils.
Why thickness matters so much
- Abrasion life. Sliding gravel and cargo wear the surface away a little at a time. More film means more material to wear through before metal is exposed.
- Gouge depth. A steel corner that cuts 1/16 inch into a 1/8-inch liner leaves a scar. In a liner that's only 1/16 inch thick, the same cut reaches metal.
- Impact cushioning. A thicker elastomer layer absorbs more energy before force reaches the bed. See our guide to impact and chemical resistance.
- Barrier. A continuous, adequately thick film keeps water, salt and chemicals away from the metal.
There are diminishing returns, though. Extra thickness adds cost and weight. On tight-fitting parts like tailgates, it can affect clearances. And extra material sprayed in a hurry can be less uniform. The goal isn't "as thick as possible." It's thick enough everywhere, and thicker where it counts.
A liner that averages 150 mils but drops to 40 mils in the corners will fail in the corners. Ask your applicator how they make sure corners, seams and edges get full build. Those areas are the hardest to spray evenly.
Zone-by-zone thickness
Damage in a truck bed isn't evenly spread. The floor, the tops of the wheel wells, the front bulkhead and the tailgate take most of the abuse. Smart specs put material where it's needed:
| Zone | Daily driver / light hauling | Contractor / heavy hauling |
|---|---|---|
| Floor | Standard build (about 125 mils) | Upper end of the common range (toward 1/4 inch) |
| Wheel-well tops | Standard to heavy | Heavy |
| Front bulkhead | Standard | Heavy, where cargo slides forward under braking |
| Side walls | Standard | Standard |
| Rail caps (over-rail) | Standard to light | Standard; pad rack clamps |
| Tailgate inner face | Standard | Heavy, with clearance checked |
These are planning guidelines, not product instructions. Your applicator should set target thicknesses based on the specific system and its data sheet. Fleet managers can find more in our fleet bedliner spec guide.
Texture: grip, cleaning and the "peaks" problem
| Texture | Grip | Cleaning | Best for |
|---|---|---|---|
| Fine / smooth | Moderate | Easiest | Sliding pallets, bed slides, crates |
| Standard | Good | Easy | Most trucks; mixed cargo |
| Aggressive | Highest | Hardest; holds dirt | Loose tools, bikes, steps, trailer ramps |
Texture is formed by how the coating is sprayed, typically with a final pass that leaves droplets standing on the surface. Those peaks feel substantial, but they aren't the protective layer. They wear down first. When a shop quotes thickness, ask whether that's the continuous base film or a measurement that includes texture. For long-term durability, the base film is what counts.
You can have different textures in different zones: smoother on the floor for sliding cargo, standard on the walls, aggressive on the tailgate top where you climb in. Ask for it when you book.
Thickness converter and material estimate
Bedliner Thickness Converter
Convert a thickness between mils, inches and millimeters, and optionally estimate the coating needed for an area.
Material estimates assume a 100% solids coating with theoretical coverage of 1,604 sq ft per gallon at 1 mil, with no allowance for overspray or waste (often 10–25% in practice). 86 sq ft is a rough figure for a full-size 6.5-ft bed under rail; measure your own bed for accuracy.
Worked example: a contractor's 6.5-foot bed
Say a contractor wants a heavy floor and standard walls on a full-size 6.5-foot bed. Using rough areas and 100% solids material:
- Floor: about 34 sq ft at 175 mils → 34 × 175 ÷ 1,604 ≈ 3.7 gallons.
- Walls, front bulkhead and wheel wells: about 40 sq ft at 125 mils → about 3.1 gallons.
- Tailgate inner face: about 9 sq ft at 150 mils → about 0.8 gallons.
- Total: about 7.7 gallons net, or roughly 8.5–9.5 gallons with typical overspray and waste.
Compare that with a uniform 100-mil build on the same bed, which needs closer to 5 gallons. That's in line with ArmorThane's estimate of about 5 gallons for a full-size bed at roughly 100 mils, and it shows why a heavy-duty spec costs more. The extra material goes exactly where a work truck needs it.
Steel, aluminum and composite beds
Not every bed is stamped steel anymore. Ford's F-150 moved to aluminum-alloy body panels, including the bed, starting with the 2015 model year, and several trucks now use composite inner beds. The bed material doesn't change the thickness logic much, since cargo still hits the floor and wheel wells hardest, but it does change prep and verification:
| Bed material | Prep considerations | How thickness is checked |
|---|---|---|
| Steel | Abrade, treat any rust to sound metal, prime bare spots as the data sheet specifies | Magnetic-induction gauge |
| Aluminum | Aluminum's oxide layer resists adhesion; use the abrading method and primer the coating maker specifies for aluminum | Eddy-current gauge |
| Composite or plastic | Adhesion varies by material; ask the applicator how they prep and test it, and what the warranty says | Ultrasonic gauge or a small destructive check |
On any material, edges deserve extra attention. The rail tops, tailgate edges and the seam where the floor meets the front wall are where film tends to run thin and where lifting starts. A good applicator builds those areas deliberately rather than letting overspray cover them.
How thickness is verified
On steel beds, coating thickness can be measured non-destructively with magnetic-induction gauges. Aluminum beds use eddy-current gauges, and DeFelsko describes both methods for bedliners. Non-metal beds and composites need different methods, such as ultrasonic coating gauges or a small destructive check in an inconspicuous spot. Many applicators also track material used per job, which gives an average film build. Ask your shop how they check thickness, and ask for a few readings on the floor and walls.
Thickness mistakes to avoid
- Accepting a quote that never states a thickness.
- Confusing texture height with protective film thickness.
- Building heavy on easy flat areas and thin in corners and seams.
- Over-building the tailgate without checking clearances to the bed and bumper.
- Choosing a thin DIY coating for a truck that hauls rock or steel every day.
Thickness and chemistry work together. A thick film of a soft material behaves differently from a thinner film of a harder one. Our explainer on bedliner test specs shows how to read the material side of the equation.
Frequently asked questions
Is thicker always better for a bedliner?
Up to a point. More film improves abrasion life, gouge protection and impact cushioning, but it adds cost and weight and can affect tailgate clearances. The best approach is adequate thickness everywhere, with extra build in high-wear zones.
How thick is a DIY roll-on bedliner?
Much thinner than a professional spray-on, typically a fraction of the 125–250 mils common for pro liners, depending on the product and number of coats. That's why DIY coatings wear through faster in high-traffic areas.
Can extra thickness be added later?
Yes. A worn or thin liner can be cleaned, scuffed and recoated to add build. The new layer bonds best when the surface is properly prepped, so let your applicator handle it.
Does texture make the liner thicker?
Texture adds surface peaks, but those wear down first and don't provide the same protection as the continuous base film. Ask for base film thickness when comparing quotes.
Talk to an applicator
ArmorThane makes spray-on bedliner systems and has a network of independent applicators. Get a quote or find an installer near you.
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