Tile Lippage & Warpage Calculator

Every tile is a little warped, so no floor is perfectly flush. The industry standard (ANSI A108.02) allows 1/32 in of lippage between neighbouring tiles with joints under 1/4 in, plus the warpage the tile itself is allowed under ANSI A137.1. Enter your tile to see how much is acceptable, the narrowest grout joint you should use and the largest offset for a running bond.

Your tile

Tile length (in)

Tile width (in)

Tile type

Grout joint

Inches

Layout

Allowable lippage

0.081 in (5/64)

Allowable edge warpage: 0.050 in
Allowable diagonal warpage: 0.070 in
Minimum average joint: 0.175 in (11/64)
Maximum running-bond offset: 33% of length
Substrate flatness: 1/8 in in 10 ft, 1/16 in in 24 in

Your 1/8 in joint is narrower than the 11/64 in minimum for this tile in a running bond.

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Tools the pros use for this job

Tile Leveling System
DGSL Tile Leveling System with Plier, 300 Tile Spacers 1/8" and 100 Wedges
$25.99
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Holds neighbouring edges flush while the thinset cures — the main tool against lippage on large tile.
Long Straightedge
Long Straightedge
Check substrate flatness and tile warpage before you set a single piece.
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Check substrate flatness and tile warpage before you set a single piece.
Feeler Gauges
Feeler Gauges
Measure the actual lippage or bow against the limits on this page.
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Measure the actual lippage or bow against the limits on this page.

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ANSI A137.1 warpage limits by tile type

Allowable warpage, % of edge or diagonal, or the cap in inches — whichever is less

Tile type	Edge	Diagonal
Porcelain ≥ 6 in, rectified	0.4% or 0.05 in	0.4% or 0.07 in
Porcelain ≥ 6 in, calibrated	0.5% or 0.08 in	0.5% or 0.08 in
Pressed floor tile ≥ 6 in, rectified	0.4% or 0.05 in	0.4% or 0.07 in
Pressed floor tile ≥ 6 in, calibrated	0.5% or 0.08 in	0.5% or 0.08 in
Pressed floor tile, natural (unsorted)	1% or 0.12 in	0.75% or 0.13 in
Glazed wall tile ≥ 6 in	0.4% or 0.05 in	0.4% or 0.07 in
Quarry tile	1.5% or 0.18 in	1% or 0.17 in
Mosaic	1%	0.75%
Gauged porcelain panel / slab	0%	0%

From the ANSI A137.1 table reproduced in LATICRETE TDS 164. Gauged porcelain is governed by its own lippage limit (1/32 in, nothing added).

Allowable lippage for common sizes (rectified porcelain, 1/8 in joint)

Lippage limit = 1/32 in + allowable edge warpage on the longest edge

Tile	Edge warpage	Lippage limit	Max running-bond offset	Substrate flatness
12 × 12 in	0.048 in	0.079 in (5/64)	any	1/4 in in 10 ft, 1/16 in in 12 in
12 × 24 in	0.050 in	0.081 in (5/64)	33%	1/8 in in 10 ft, 1/16 in in 24 in
24 × 24 in	0.050 in	0.081 in (5/64)	33%	1/8 in in 10 ft, 1/16 in in 24 in
24 × 48 in	0.050 in	0.081 in (5/64)	33%	1/8 in in 10 ft, 1/16 in in 24 in
8 × 48 in	0.050 in	0.081 in (5/64)	33%	1/8 in in 10 ft, 1/16 in in 24 in
48 × 48 in	0.050 in	0.081 in (5/64)	33%	1/8 in in 10 ft, 1/16 in in 24 in

Keeping lippage down

Check the substrate with a 10 ft straightedge first; fix it with the self leveler calculator rather than with extra thinset.
Back-butter large tile and use the trowel the trowel size calculator gives you, so there are no voids to rock on.
Use a leveling clip system on anything 15 in and up — the tile leveling clip calculator counts them.
Keep to a 1/3 offset or a grid with large tile; see the large-format tile calculator for waste and thinset.
Raking light from a window or wall-washer makes acceptable lippage look worse; judge it standing up in normal room light.
Step-by-step prevention is in our guide to avoiding lippage on large-format tile.

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How this calculator works

Warpage is measured as a percentage of the edge or diagonal (ASTM C485) and capped at a fixed maximum, whichever is less. The calculator takes your tile type's ANSI A137.1 percentage, applies it to the longest edge and the diagonal, and applies the cap. Allowable lippage is then 1/32 in (joints under 1/4 in) or 1/16 in (joints 1/4 in and wider) plus that edge warpage — except gauged porcelain panels, which are held to 1/32 in flat.

For a running bond with any side longer than 18 in, ANSI A108.02 4.3.8.1 sets a minimum average joint of 1/8 in for rectified tile and 3/16 in for calibrated tile, plus the tile's edge warpage, and 4.3.8.2 caps the offset at 33% of the tile length. Tiles with an edge of 15 in or more need a flatter substrate: 1/8 in in 10 ft rather than 1/4 in.

Frequently asked questions

How much lippage is acceptable in tile?

Under ANSI A108.02: 1/32 in (0.8 mm) for grout joints from 1/16 in up to 1/4 in, and 1/16 in (1.6 mm) for joints 1/4 in or wider — each plus the allowable warpage of the tile itself. Gauged porcelain panels and slabs are held to 1/32 in with nothing added.

How much tile warping can a tiler work with?

The tile is allowed the warpage in ANSI A137.1, and the installer is allowed 1/32 in of lippage on top of that. For rectified porcelain 6 in and larger that warpage is 0.40% of the edge, capped at 0.05 in — about 0.05 in on a 24 in tile — so neighbouring edges of a 12 × 24 can legitimately sit about 0.08 in apart. Beyond that, reject the tile or change the layout: a 1/3 offset, a wider joint or a leveling system.

Why can't I use a 50% offset with large tile?

Large tiles are bowed slightly high in the middle. A half offset puts the high centre of one tile next to the low ends of its neighbours, doubling the visible lippage. ANSI A108.02 limits the offset to 33% when the offset side is longer than 18 in, unless the tile maker says otherwise.

What is the minimum grout joint for 12 × 24 tile?

In a running bond, at least 1/8 in on average for rectified tile and 3/16 in for calibrated tile, each widened by the tile's actual edge warpage. A rectified 12 × 24 with 1/32 in of edge bow needs about 5/32 in. In a straight grid, 1/16 in is the absolute minimum, but most makers recommend 1/8 in or more.

How flat does the floor need to be for large tile?

For tile with any edge of 15 in or longer, ANSI A108.02 asks for no more than 1/8 in variation in 10 ft and 1/16 in in 24 in. Smaller tile needs 1/4 in in 10 ft and 1/16 in in 12 in. A self-leveler is the usual fix where the floor fails the straightedge test.

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Last updated: August 26, 2026 · Reviewed by the Smart Tile Calculator editorial team