Measure it twice.
A replacement window handle may have the right finish, the right general shape and even the familiar 43 mm screw spacing, yet still foul a blind, miss the gearbox, expose old fixing marks or bind because its spindle projects several millimetres too far.
Why gamble?
To measure a window handle correctly, record four dimensions: the exposed spindle length, the centre-to-centre distance between fixing screws, the width and height of the mounting base, and the handle’s projection from the window frame. Then confirm the spindle width, handle type, handing and locking function.
That is the practical answer. But the details matter.
The basic window handle measurements are simple enough to take with a steel rule or digital caliper. The problem is that people often measure from the wrong surfaces.
| Measurement | Where to measure | What it controls | Common mistake |
|---|---|---|---|
| Spindle length | From the rear face of the handle base to the spindle tip | Engagement with the espagnolette gearbox | Measuring the entire handle body and spindle together |
| Fixing centres | From the centre of one screw to the centre of the other | Alignment with existing threaded holes | Measuring from the outer edges of the screw heads |
| Base dimensions | Maximum height and width of the mounting plate | Frame fit, old-mark coverage and clearance | Assuming every 43 mm handle has the same base |
| Handle projection | From the mounting surface to the furthest outward point | Clearance from blinds, curtains, reveals and adjacent hardware | Measuring lever length instead of outward projection |
For many modern espagnolette—or “espag”—handles, 43 mm fixing centres and a 7 mm square spindle are common. They are not permission to stop measuring.
The Glutz 5039/5616 CF specification, for example, pairs 43 mm fixing centres with a 7 × 38 mm spindle. Randi supplies some window handles with the same 43 mm centres but offers spindle lengths of 35, 43, 53 or 63 mm and either 7 × 7 mm or 8 × 8 mm spindle sections. One dimension can match while another quietly ruins the replacement. Glutz’s technical product data and Randi’s window handle specifications make that variation explicit.
Do not begin with the tape measure. Begin with the mechanism.
A buyer who confuses a cockspur handle with an espag handle does not have a measurement problem. They have selected the wrong product family.
An espag handle uses a square spindle to operate an internal espagnolette gearbox or shoot-bolt system. It is common on uPVC, aluminum and some timber casement windows.
Typical identifying features include:
The CHIER door and window handles range shows why “window handle” is too broad a buying description: casement, spindle, fork, sliding and other configurations sit within the same product category but use different interfaces.
A cockspur handle closes by pushing a projecting nose or spur over a wedge fixed to the frame. There may be no square operating spindle at all.
For this type, measure:
Trying to substitute an espag handle because the base “looks about right” is bad practice. The mechanisms do different jobs.
Tilt-and-turn systems may also use 43 mm fixing centres and a square spindle, but operating positions, lock logic and spindle engagement must match the complete window system.
Some models include tilt-before-turn, lockout or restricted-operation functions. A generic handle can physically attach and still defeat the intended operating sequence.
Fork or blade handles connect to the lock through a shaped drive component rather than a conventional square spindle. Photograph the drive from the rear, record every dimension and identify the original system where possible.
The hard truth? “Close enough” does not exist at a mechanical interface.
Remove the existing handle before recording the spindle and fixing pattern. You cannot measure the hidden interface accurately while the handle remains attached.
Keep the window closed or otherwise safely supported before removing operating hardware. Do not leave an upper-floor opening unsecured.
Turn the handle to expose its fixing screws. Depending on the design, you may need to rotate or lift a decorative cover plate.
Remove the screws by hand with the correct screwdriver bit. I prefer hand tools here because a powered driver can strip a worn head, crack a plastic cover or pull a threaded insert loose before you realise the screw is binding.
Pull the handle straight away from the sash. Avoid twisting it aggressively; the spindle may still be engaged in the gearbox.
Keep the original screws.
But do not assume you should reuse them. Screw diameter, thread, head form and usable length must suit the replacement base and the existing reinforcement or gearbox.
The spindle is the square metal bar extending from the rear of an espag or tilt-and-turn handle.
Measure from the flat rear mounting face of the base—not from a raised decorative cover—to the end of the metal spindle. This is the exposed spindle length or spindle projection.
Record the figure in millimetres. A digital caliper is best, but a rigid rule is adequate when the spindle end is square and undamaged.
For example:
Do not round 17 mm down to 15 mm merely because 15 mm appears in a product menu. Check how deeply the existing spindle engages and whether the proposed replacement is designed to be cut or interchanged.
The ERA Maxim Universal Multi-Spindle handle is supplied with 9, 15, 30, 43 and 55 mm pre-cut spindles. ASSA ABLOY’s Mila Universal handle uses five interchangeable spindle lengths covering 15–55 mm. These products solve a real compatibility problem, but they do not make every other dimension universal. ERA’s Maxim handle specification and ASSA ABLOY’s Mila product data confirm the available spindle options.
Also measure the spindle section. The common uPVC espag size is 7 × 7 mm, or approximately 0.276 × 0.276 inches, but 8 × 8 mm versions exist.
A 7 mm spindle rattling in an 8 mm input is not “nearly right.” It is clearance where positive drive should be.
Fixing centres are measured from the centre of one fixing screw to the centre of the other.
Not edge to edge.
Not screw-head to screw-head.
Centre to centre.
When both screw holes are the same diameter, an easy method is to measure from the left edge of the upper hole to the left edge of the lower hole. Measuring matching edges produces the same centre-to-centre result and is often easier than estimating the middle of each opening.
Many espag handles use 43 mm fixing centres. That equals approximately 1.69 inches. Manufacturer specifications from Glutz and Randi support 43 mm as a widely used configuration, while also showing that spindle sizes and lengths still vary.
So yes, 43 mm is common.
No, it is not a complete specification.
If the handle uses three, four or asymmetrical holes, draw the pattern on paper and record the horizontal and vertical distance between every centreline. A photograph with a rule in frame also helps a supplier understand the orientation.
Measure the maximum width and height of the base or backplate where it contacts the window sash.
Then record:
Why so much detail?
Because two handles can share a 43 mm fixing pattern while using visibly different bases. A replacement with a narrower plate may expose discoloration, compressed gasket marks, old paint lines or machining around the previous handle.
A wider base creates a different problem. It may overhang a narrow aluminum profile, contact a glazing bead or sit across a curved surface instead of mounting flat.
For model-specific drawings, the CHIER technical download centre is the more reliable internal route than guessing from product photographs; it separates mounting-centre drawings, base dimensions, spindle information and CAD files by product family.
Projection is the perpendicular distance from the mounting surface of the sash to the outermost point of the installed handle.
Place a straightedge across the furthest point of the lever, parallel with the window surface. Measure back to the plane where the handle base meets the sash.
Record the handle position used for the measurement:
“Projection: 45 mm” is meaningless when nobody states whether the lever was closed or extended.
Projection matters when a window sits behind:
This is where many replacement guides become lazy. They treat projection as cosmetic, yet an extra 8–12 mm can make a blind catch every time the window is operated.
Inline espag handles usually work on left- or right-opening windows because the lever aligns with the spindle centreline.
Cranked handles are different. Their lever bends or offsets to one side, so handing and clearance can matter.
Stand inside the building and photograph the closed handle. Record:
Do not trust product images alone. Sellers may photograph one hand and supply another variant under the same listing.
I would send a supplier the following schedule rather than a message saying, “I need the same black handle.”
| Specification field | Example entry |
|---|---|
| Window type | Side-hung uPVC casement |
| Handle system | Inline espag |
| Spindle section | 7 × 7 mm |
| Exposed spindle length | 30 mm |
| Fixing centres | 43 mm |
| Base size | 65 × 17 mm |
| Closed projection | 52 mm |
| Lever direction when locked | Down |
| Handing | Reversible |
| Locking function | Key-locking |
| Finish | Matte black |
| Screw specification | M5; length to be confirmed |
| Quantity | 200 units |
| Supporting files | Front, rear and installed photographs |
This format works for a single household replacement and scales into an OEM request.
For larger programs, the CHIER OEM/ODM window handle process asks buyers to match bases, mounting centres, spindles or forks, handing and lock interfaces to the actual profile before production release. That is the right order. Geometry first. Finish later.
A handle can match every number in your notebook and still be the wrong replacement.
With the old handle removed, inspect the square gearbox input. Look for:
If the original handle turned without moving the locking points, the handle may not be the failed component. A worn or broken gearbox can make a new handle feel loose from day one.
I dislike the industry habit of selling handles as isolated objects. The user turns a handle, but the resulting load travels through the spindle, gearbox, rods, cams, keeps, gaskets, frame and sash.
Reviewing how window hardware affects daily operating comfort is useful here because handle geometry, lock resistance and frame alignment are one operating experience, not separate departments.
A replacement handle may include screws intended for another profile depth.
Screws that are too short may engage only a few threads. Screws that are too long can bottom out, distort a gearbox casing, contact moving components or give a false impression that the base is tight.
Compare:
Do not shorten structural or machine screws casually unless the supplier permits it and the cut end can still start cleanly.
Match the original operating requirement:
A key-locking handle is not automatically a complete security solution. And a lock is not a substitute for a properly specified window restrictor where fall prevention is required.
A measurement-perfect handle can still be a poor choice for a coastal, poolside or high-cleaning environment.
Confirm the body material, spindle material, fasteners, finish system and exposure class. The phrase “aluminum alloy” does not tell you the casting route, pretreatment, coating thickness or galvanic pairing.
For specification work, use the material selection guide for aluminum window handles before approving a sample solely because the finish looks clean.
A badly fitted handle is irritating. A badly controlled window opening can be far worse.
The U.S. Consumer Product Safety Commission reported in April 2026 that an estimated 5,600 children aged 12 and under received emergency-department treatment in 2024 after falling from windows. About one-third required hospitalization, and CPSC was aware of at least 25 child deaths from window falls between 2021 and 2023. Read the CPSC’s 2026 Window Safety Week release.
Those numbers deserve more attention than another argument about satin chrome versus matte black.
The UK Health and Safety Executive advises that openings intended to protect people at risk should generally be restricted to 100 mm or less, equivalent to approximately 3.94 inches, with disengagement requiring a special tool or key where appropriate. Review the HSE guidance on falls from windows.
And there is a real warning behind the guidance. A UK Department of Health alert followed an incident in which a patient died after falling from a second-floor hospital window; the restrictor could be forced beyond the intended 100 mm limit. The government safety alert states plainly that nominal restriction is not enough if the installed device cannot resist foreseeable force.
This does not mean a replacement window handle must solve every safety risk. It means the person replacing the handle must not accidentally disable a restrictor, defeat an operating sequence, create unreliable locking feedback or assume that a key-locking lever makes the entire opening safe.
For commercial, healthcare, education or multi-unit housing work, compare the proposed hardware against the project’s documented requirements and the CHIER aluminum window hardware compliance guide. Component fit and assembly compliance are related, but they are not the same claim.
The measurements needed for a replacement window handle are the exposed spindle length, spindle width, centre-to-centre fixing-screw distance, mounting-base height and width, and outward handle projection, together with the handle type, handing, offset and locking function. These values establish mechanical engagement, hole alignment, frame coverage and operating clearance.
Photograph the installed handle, its rear interface and the window profile. For espag handles, also confirm whether the spindle is 7 × 7 mm or 8 × 8 mm.
Window handle spindle length is the distance from the flat rear mounting face of the handle base to the end of the projecting square metal bar. Remove the handle, place a rule or caliper against the rear face, and record only the exposed spindle in millimetres, excluding the handle body.
Do not measure from the front cover plate. Also check the spindle’s square section because identical lengths do not guarantee identical gearbox engagement.
Window handle screw centres are measured from the exact centre of one fixing hole to the exact centre of the other fixing hole. When both holes have equal diameters, measuring between matching edges—left edge to left edge, for example—produces the same centre-to-centre dimension and reduces estimation error.
A 43 mm distance is common on espag handles, but the base, spindle, handing and function still need separate verification.
Not all uPVC window handles use the same interface, although many modern espagnolette handles use 43 mm fixing centres with a 7 mm square spindle. Cockspur, fork, blade, tilt-and-turn and proprietary systems may use different mounting patterns, drive connections, step heights, spindle lengths or operating functions, so identify the mechanism first.
Even among 43 mm espag handles, manufacturers offer different spindle projections, base widths, lever offsets and locking options.
Window handle projection is the perpendicular distance from the window’s mounting surface to the handle’s furthest outward point in a stated operating position. It determines whether the lever clears blinds, curtains, shutters, deep reveals, secondary glazing and nearby sashes, and it should not be confused with the lever’s overall length.
Always state whether you measured projection with the handle closed, open at 90 degrees or in its maximum operating position.
A replacement spindle may be cut only when its manufacturer allows shortening and sufficient engagement will remain inside the gearbox after cutting. The finished end must stay square, straight and free from burrs; an undersized, angled or poorly deburred spindle can bind, wobble or provide too little contact area for reliable operation.
An interchangeable multi-spindle handle is usually a cleaner option when the required length falls within the supplied range.
Do not order from appearance alone.
Remove the old handle. Identify its operating system. Measure the exposed spindle, fixing centres, base and projection in millimetres. Confirm spindle width, handing, screw specification and locking function. Photograph everything.
Then test the replacement on the real window before committing to volume.
For a one-off repair, that process prevents a frustrating return. For an OEM, distributor or window-system program, it prevents incorrect machining, exposed fixing marks, lock damage, blind interference and repeat-order drift.
Start by comparing the door and window handle range, obtain the relevant dimensions through the technical download centre, and submit your profile drawing or reference sample through the OEM/ODM window handle program.
Send dimensions, not guesses.
