What Size Mitre Saw Do You Need for UK Skirting and Architrave?

The useful version of this question is not "what size mitre saw" but "how wide is the widest thing I will cut, and which way up will it be lying when I cut it". Answer those two and the blade size falls out of them. Answer them wrong and you own a saw that does architrave beautifully and cannot reach across a skirting board, which is the most common mis-buy in this category.

It is also a specifically British question, because UK trim comes in its own sizes. Skirting is sold in a fixed ladder of heights with 144 or 145mm as the default. Architrave is 69 x 18mm unless somebody chose otherwise. Coving is a symmetrical cove that must not be cut lying flat. Those three facts, not the badge on the saw, decide whether you need a 210mm chop head or a 255mm slide. What follows sizes the job against the crosscut figures Evolution, DeWalt and Einhell publish for the saws in our top 7 mitre saws ranking. Nothing on this site is bought or handled: the capacities below are the makers' own published numbers, and where a figure is arithmetic on top of them, it says so.

The short answer

UK trim sizes are the input

UK skirting is sold in a standard ladder: 44, 58, 68, 94, 119, 144 or 145, 168 or 169, 194 and 219mm, in 15, 18 and 25mm thicknesses. If you have to guess without measuring, 144 or 145mm is the default in most UK homes and the safest single answer. The 94 to 119mm end reads as new build; 194 to 219mm belongs to period property and barn conversions. Architrave is simpler: 69 x 18mm is the standard, with 95 x 18mm as the wider option for taller rooms and heavier doors, and one 4.4m length usually covers both legs of a door.

Those numbers map straight onto a saw's spec sheet, because a published capacity is written as width by depth: the width is how far the blade travels across the board, the depth is how thick the board can be. Skirting laid flat on the table is a 144mm-wide, 18mm-thick workpiece. Architrave laid flat is a 69mm-wide, 18mm-thick workpiece. Depth is never the constraint on trim. Width is the whole game.

210 and 216mm: the UK trim size

The 210 and 216mm blades are what the UK shelf is built around, and there are two completely different tools wearing that blade size.

A fixed head only drops, so its crosscut is limited to roughly the blade diameter. Evolution publishes 125 x 55mm at 0 degrees on the R210CMS and 85 x 55mm once the table swings to 45. Einhell publishes 120 x 55mm and 80 x 32mm on the TC-MS 2112. Read those against the skirting ladder and the verdict is blunt: a fixed 210mm head is an architrave saw. It will mitre 69 x 18mm architrave all day with room to spare, it will take beading, stud work and 94mm skirting, and it cannot reach across a 144mm skirting board lying flat at any angle, including a square cut. That is not a criticism of the saws - both are well rated and cheap to own - it is a sizing fact people discover on the second day of a job.

A sliding head on the same blade is a different machine. Evolution publishes 230 x 65mm at 0 degrees and 150 x 65mm at 45 degrees on the R210SMS+, and Einhell publishes a 310mm drag capacity on the TC-SM 2131/1 Dual. DeWalt publishes a 250mm crosscut at 0 degrees on the DWS774-GB, on a 216 x 30mm blade turning at 4,500rpm. That is the size band where the UK default skirting height becomes cuttable, and it is why so many British second-fix chippies run a 216mm slider rather than something bigger.

What swinging to 45 degrees costs you

Every capacity in a spec sheet is quoted at 0 degrees first, and the 0 degree figure is not the one that matters for trim, because skirting and architrave corners are mitres. The geometry is simple: rotating the table to 45 degrees multiplies the usable width by the cosine of 45, about 0.71. Evolution's own figures for the R255SMS-DB+ are exactly that - 300mm at 0 degrees becomes 212mm at 45 - and the rest publish slightly under it, which is a maker being conservative rather than a different rule.

So the working shortcut, derived from the published pairs rather than printed by anyone, is: take about 70 per cent of the quoted 0 degree crosscut and size to that. A saw that advertises 120mm gives you 80mm on a mitre. A saw that advertises 230mm gives you 150mm. Buy against the small number.

Where a cell says not published, it is not published. Those three makers do not print a 45 degree figure for those models, and borrowing one from a sibling in the same range is how wrong numbers get into circulation - Einhell's TC-SM 2131/1 and 2131/2 do not carry identical data, and the difference matters.

254 and 255mm: what the bigger blade actually buys

Going up to a 254 or 255mm blade is usually sold as more power. In trim work it is really two things: depth and mitre width. Evolution publishes 300 x 90mm at 0 degrees on the R255SMS-DB+ and 212 x 90mm at 45 degrees. The 90mm of depth is the part a 210mm saw cannot give you at any price - that is a 90 x 90mm newel post or fence post in a single pass. The 212mm at a mitre is what puts 169mm and 194mm skirting inside capacity, and period-property skirting is exactly the case where the smaller saws run out.

What it costs is weight. That saw is 18.3kg against 12kg for the DeWalt and 5.8kg for the Evolution chop saw, which is the difference between a tool you carry upstairs one-handed and one that needs two hands and a stand waiting for it. If your work is a room at a time in occupied houses, that matters more than 60mm of extra capacity.

Flat on the table, or standing against the fence

This is the part that decides more purchases than blade diameter, and it is the question most sizing guides skip.

Skirting can be cut two ways. Lying flat on the table, the board's height becomes the width the blade has to travel - 144mm of crosscut for a 144mm board - and the corner is set on the mitre scale. Standing upright against the fence, the way it will sit on the wall, the blade only has to travel through 18mm of thickness, and the board's height becomes a vertical measurement instead.

On a bigger workshop machine, standing it up is the standard trick for tall skirting, and those saws publish a separate vertical capacity for it. None of the saws in this category do. Evolution, DeWalt and Einhell publish width and depth for stock lying flat, and nothing for a board stood against the fence, so there is no number here to size against. The depth figures that are published run from 32 to 90mm, which tells you the blade is not clearing a 144mm board stood on edge on these machines. In practice, on this size of saw in the UK, skirting is cut lying flat and the 45 degree crosscut figure is the number to buy against. If you specifically want to cut upright, measure the fence height and the blade's reach on the actual saw before you commit, because it is not on the spec sheet.

There is one honest workaround for a board slightly over capacity: cut halfway, turn the board over keeping the same edge against the fence, and finish the cut from the other face. It works, it is how a lot of 169mm skirting gets cut on a 210mm slider, and it costs accuracy - the two halves of the cut have to meet exactly, and on a mitre any misalignment shows on the face of the joint.

Coving is cut in position, not flat

Coving looks like it should be the hardest cut on the job and it is the easiest, provided you do not lay it down. Square corner, any UK cove, any size, any brand: mitre 45 degrees, bevel 0, with the piece held in the saw at the angle it hangs on the wall. Ceiling edge flat on the table, wall edge flat against the fence, decorative face towards you - upside down and backwards from how it will hang. DeWalt describes the same position for crown moulding in its mitre saw manual. That is the entire reason a plastic coving mitre box works, and why the bevel scale never enters into it.

Plaster cove should never be cut lying flat. The precondition for the flat compound method in DeWalt's manual is that the moulding lies with its broad back surface down on the table, and a cove has no broad flat back - only two narrow lands at its edges. Face up it rests on two thin lines, rocks under the blade and cannot be secured against the table and the fence the way the same manual requires.

Where coving does affect saw size is the fence. British Gypsum publishes the cove size for Gyproc Cove 100 and Cove 127 but no spring angle or drop. Because a classic C profile is symmetrical, the drop is the cove size divided by the square root of two - derived, not published - which puts Cove 100 at about 71mm down the wall and Cove 127 at about 90mm. Nested in the saw, a Cove 127 therefore occupies roughly 90mm up the fence and 90mm across the table, plus whatever packer you slip behind it. Check that against your saw before you buy the coving rather than after.

Timber and MDF crown moulding is the exception, because it does have a flat back and can be cut lying down. For a 45/45 spring angle at a square corner that is a mitre of 35.26 degrees and a bevel of 30.00. DeWalt casts a hard 30 degree bevel pawl for exactly that cut, which is maker-level confirmation of the number; there is no detent anywhere for 35.26, so it gets set by eye between the 35 and 36 marks.

Single or double bevel on a long run

Bevel is the blade tilting out of vertical; mitre is the table rotating. Whether you need both directions depends entirely on the previous two sections.

• Coving nested, and skirting stood against a fence: the bevel stays at 0 all day. A single bevel saw is not a compromise here, it is simply enough.
• Skirting and crown cut flat: the corner is now set on the bevel scale, and a single bevel head tilts one way only. Every opposite-hand corner means picking the length up, turning it end for end and re-marking it - and on a profiled board, a torus or an ogee, turning it over puts the profile the wrong way up. Over a room that is a lot of handling and a lot of chances to cut the wrong way.

Two saws in this category bevel both ways: the Evolution R255SMS-DB+ 255mm Double Bevel Sliding Mitre Saw and the Einhell TC-SM 2131/1 Dual 210mm Double Bevel Sliding Mitre Saw. One caveat on the Einhell, worth knowing before you order - the Amazon listing quotes plus or minus 45 degrees mitre and plus or minus 47 degrees bevel, while Einhell's own UK data for the sibling TC-SM 2131/2 has those two figures the other way round. Both agree it tilts in both directions, which is the part that decides the purchase, but treat the exact degree figures as approximate.

Your corners are not 90 degrees

Almost every sizing guide assumes a square room. UK housing stock does not oblige, and a Victorian or Edwardian terrace is routinely a degree or two out on every corner in the room - not the same degree or two, either.

On any saw sold today the setting is (180 minus the measured wall angle) divided by 2. An 87 degree corner needs 46.5 on each piece; a 93 degree corner needs 43.5. The folk rule everyone repeats - measure the corner and halve it - is only right on the older style of scale that started at 90 and counted down. Every modern saw starts at 0 and runs both ways, so you subtract from 180 first. Our free mitre and bevel angle calculator does that arithmetic, plus frames with any number of sides and coving at any spring angle, and prints an angle table you can take to the saw.

Two consequences for sizing. First, out-of-square corners eat into the mitre range, so the 50 degree mitre swing on the Evolution sliders and the 50 degree quick release on the DeWalt are worth more in an old house than they look on paper - a bay window is a 135 degree corner and wants 22.5. Second, squareness of the saw itself matters more than capacity for the look of the finished joint: a fence one degree out puts a degree into each half of the joint, and 125mm multiplied by the tangent of 2 degrees is about 4mm of open mitre. On 150mm skirting it is nearer 5mm. That is visible from the doorway on a saw of any size.

The related trick worth knowing is that internal corners on skirting should be scribed, not mitred: cut the first piece square into the corner, then cut the second at the mitre angle and follow the profile line with a coping saw so it sits over the face of the first. A scribed joint stays closed when the house moves, and it copes with an out-of-square corner without any adjustment. It also quietly solves the capacity problem on tall skirting, because the first piece is only a square cut - a 219mm board needs 219mm at 0 degrees, which the 300mm and 310mm sliders here have, where no saw in the category can mitre it flat. External corners are still mitred and glued.

So what size do you need?

Architrave, beading and trim only. A 210mm fixed head. The Evolution R210CMS 210mm Compound Mitre Saw publishes positive mitre stops at 0, 15, 22.5, 30 and 45 degrees and weighs 5.8kg, and its supplied blade will take mild steel and nail-embedded timber as well as wood. The Einhell TC-MS 2112 210mm Compound Mitre Saw is the volume seller, with 1,600W at 5,000rpm on a 48-tooth blade that cuts cleaner in softwood and coated board, and more owner ratings than anything else in the category. Neither will reach across a 144mm skirting board.

Architrave plus standard 144 or 145mm skirting. A 210mm slide is the smallest thing that does it, and the Evolution R210SMS+ 210mm Sliding Mitre Saw is the one with the published figure to prove it at 150 x 65mm on a mitre. If the run is long enough that flipping boards is the slow part of the day, the Einhell TC-SM 2131/1 Dual 210mm Double Bevel Sliding Mitre Saw bevels both ways and publishes the widest drag capacity here at 310mm, for a fraction of what the other double bevel saw costs.

Period skirting at 169mm or above, coving, posts, decking. The Evolution R255SMS-DB+ 255mm Double Bevel Sliding Mitre Saw, on 212 x 90mm at a mitre and 300 x 90mm square. It is the only saw here that publishes the depth for a 90 x 90mm post in one pass, and the only one that reaches 194mm skirting on a flat mitre. It is also 18.3kg.

Second fix where repeatability beats capacity. The DeWalt DWS774-GB 216mm Sliding Compound Mitre Saw. Its XPS casts the blade's own shadow across the work, so the line you see is the kerf you get and there is nothing to calibrate, unlike a laser. Positive stops at 15, 22.5, 30 and 45 with a quick release to 50, and 12kg, which is a genuine one-hand carry up a stair.

No socket within reach. The Evolution R185CMS-Li 185mm Cordless Compound Mitre Saw, sold body only - no battery and no charger in the box, so it only adds up if you already run Evolution's 18V EXT packs. Evolution publishes a 105 x 45mm crosscut, which is architrave, beading and trim, nothing wide.

219mm skirting. Scribe the internals, which are square cuts inside the capacity of any of the sliders above, and take the external mitres to a larger machine, a hand mitre box or a jig. Nothing in this category mitres a 219mm board lying flat.

One thing to check before you click buy on any of them: every corded saw linked above is the 230 or 240V domestic version, which is what the ASINs on our ranking are. UK building sites run 110V off a yellow transformer, and the same saws exist as separate 110V products - DeWalt appends -LX, so the site version of the DWS774-GB is the DWS774-LX, and Evolution and Einhell list 110V as different SKUs. They are not interchangeable.

Read next

The full ranked shortlist, with the scoring rubric and the owner-rating evidence behind each pick, is our top 7 mitre saws buying guide. Before you cut anything, the mitre and bevel angle calculator turns a measured corner into a saw setting and covers coving, frames and out-of-square walls; the rest of the free tools cover fixings, model numbers and battery platforms. If you want to know how these rankings are put together and what evidence they are built on, that is set out on how we rank, and current discounts across the catalogue are tracked on our tool deals page.