Tile Trim Calculator
How much tile trim do you need? Adding up the edges and dividing by the strip length is usually right, but not always, because two edges only share a strip if they fit in it together. Enter each trimmed edge and get DIYData's cutting chart, longest first, with mitred corners allowed for.
Last reviewed: 30 September 2026
Trim
Enter each edge that needs trim: its length, how many of that length, and how many ends are mitred at a corner. A window reveal is four edges, each mitred both ends. Leave the extra allowance at 0%: the chart already counts every cut.
How Much Tile Trim Do I Need?
Add up every edge that needs trim and divide by the strip length. For most jobs that gives the right number: in the table below it matches the cutting chart in 12 of 14 cases. But it can be short. Three runs of 1300mm come to 2 strips of 2.5m by the sum, and no strip can hold two of them, so you need 3.
That is why DIYData's guide says to make a cutting chart instead: start with the longest run, add shorter runs to the same strip until it is full, then start the next. And not to join strips along a run, because the join is hard to match. This calculator does exactly that.
How the Chart Works
- One strip per run. A run is only joined if it is longer than a strip, full strips first, with no piece under 300mm (our rule). DIYData: joins along a run "should be avoided".
- Longest first. Each piece goes in the strip with least room left that still fits it, with 3mm lost at each cut. That is DIYData's cutting chart.
- Mitred corners. Homelux recommends 45 degree cuts at corners. Each mitred end adds the trim's depth, for the long point of the mitre (our rule).
What it does not do: curved edges, corner pieces or end caps, and the grout gap Homelux suggests leaving in showers, which is too small to change the strips.
Trim Sizes, With Sources
Every trim in the dropdown has a Wickes product page. Choose the depth to suit your tiles.
| Trim | Product page |
|---|---|
| PVC 10mm, 2.5m (Homelux, white) | Homelux 10mm PVC Straight White Tile Trim, 2.5m |
| Metal 12.5mm, 2.44m (Homelux, silver) | Homelux 12.5mm Metal Straight Silver Tile Trim, 2.44m |
| Metal 8mm, 2.44m (Homelux, brushed black) | Homelux 8mm Metal Straight Brushed Black Tile Trim, 2.44m |
The cutting chart and the advice against joins are from DIYData's tile trim estimating guide. The 45 degree corner cut is from Homelux's guide to fitting tile trim. The mitre allowance, the shortest piece and the saw cut are our own working.
Common Jobs: Strips Needed
Generated from the calculator above, with nothing added. Each cell is the cutting chart, then the total length over the strip length.
| Job | PVC, 2.5m | Metal, 2.44m |
|---|---|---|
| Top edge of a half-tiled wall, 2400mm | 1 (1) | 1 (1) |
| Top edges round a bath, 1700 + 700 + 700mm | 2 (2) | 2 (2) |
| Two external corners, 2000mm | 2 (2) | 2 (2) |
| Window reveal, 900 x 1200mm, mitred | 2 (2) | 2 (2) |
| Half-tiled kitchen wall, 3000 + 2400mm | 3 (3) | 3 (3) |
| Three runs of 1300mm | 3 (2, short) | 3 (2, short) |
| Shower niche, 600 x 300mm, mitred | 1 (1) | 1 (1) |
Frequently Asked Questions
How much tile trim do I need?
Add up every edge that needs trim and divide by the strip length, and for most jobs that is right. DIYData's guide says to do better than that: allocate the runs to strips longest first, because two runs only share a strip if they fit in it together. Three runs of 1300mm come to 2 strips of 2.5m by the sum, but no strip can hold two of them, so you need 3. This calculator makes that cutting chart for you. In the table below the sum matches it in 12 of 14 cases and is short in 2.
Which edges need tile trim?
DIYData says trim goes wherever the tiling finishes on the wall, and where tiles on one face meet tiles on another, as round a window recess. So the top edge of half-tiled walls, the vertical edges at external corners and boxing, and the edges of window reveals and niches. Internal corners do not need it.
How do I cut tile trim at a corner?
Homelux recommends a 45 degree cut at corners so the two pieces meet cleanly, using a mitre box, and a square 90 degree cut everywhere else. The calculator adds the trim's depth to each mitred end, because the long point of the mitre runs past the corner line (our rule).
Can I join tile trim?
Only if a run is longer than a strip. DIYData says joins along a run should be avoided because they are hard to match, so the calculator never joins two offcuts to make a run, and it tells you when a run is too long for one strip. Each strip leaves offcuts, and the plan uses them for shorter runs where they fit.
Does the strip length matter?
A little. Homelux's PVC trim is 2.5m and its metal trim is 2.44m. For the default bathroom that is 4 strips of PVC or 4 of metal. Choose the trim depth to suit your tiles first.