How to Measure Window Stays

A Practical Guide to Measuring a Window Stay

Measuring a window stay involves more than checking whether the old fitting is described as 8, 10 or 12 inches. You should also record the overall length, pivot position, fixing plate, fixing centres, stay pins and the clear space available on the timber casement.

This guide covers traditional peg-style stays used on timber casement windows. Sliding stays, quadrant stays, roller-arm stays, fanlight fittings and concealed mechanisms use different measurements and should be checked separately.

If you are ready to compare designs and sizes, visit our Window Stays Collection.

Table of Contents

What Is a Traditional Window Stay?

A traditional window stay is a perforated arm fitted to an opening timber casement. The holes along the arm locate over one or more stay pins fixed to the frame or sill, allowing the window to be held at selected opening positions.

The stay controls the open position of the casement. A separate window fastener normally performs the main closing function. For an explanation of the different fittings, read Window Furniture Explained.

This measuring guide is intended for conventional fixed-arm, peg-style stays. It should not be used as the sole guide for sliding stays, specialist fanlight stays, friction hinges or other concealed window mechanisms.

What Do 8, 10 and 12-Inch Window Stays Mean?

Many traditional stays are sold in named sizes such as 8, 10 and 12 inches. This gives you a useful starting point, but it should not be treated as the only measurement.

The named size may refer to the stay arm or another principal product dimension rather than the exact distance from the decorative tip to the far edge of the fixing plate. Different designs can therefore have different overall lengths even when they carry the same named size.

Product drawings may list several dimensions, including:

• Overall length
• Stay-arm length
• Fixing-plate size
• Fixing centres
• Pin or lug dimensions

Always compare the same measurement on the old and new fittings. Do not assume that every 10-inch stay has the same plate, hole pattern or end-to-end length.

Which Window Stay Measurements Do You Need?

For a reliable replacement, record the following measurements where possible:

Record measurements in millimetres even if the product is sold in inches. Millimetres make it easier to compare fixing centres and smaller plate dimensions accurately.

How to Measure an Existing Window Stay

If the existing stay works correctly, measure it before removing it. Take photographs of the fitting in both its open and closed positions so you have a record of its orientation and relationship with the pins.

1. Close the window and allow the stay to rest naturally over its pins.
2. Measure the complete end-to-end length of the fitting.
3. Measure from the centre of the pivot or knuckle to the furthest end of the arm.
4. Measure the fixing plate and its screw-hole centres.
5. Measure the pin plates and record the distance between their positions.
6. Open the window and note which stay holes provide useful opening positions.
7. Check the clearance around the arm, glazing bead, frame and fastener.

Do not rely only on the number of holes along the arm. Hole quantity and spacing can vary between styles and sizes.

Keep the old stay until the replacement has been installed and tested. It remains the most useful reference for position and operation.

 

How to Measure the Fixing Plate and Screw Holes

The fixing plate is attached to the opening casement and contains the pivot for the stay arm. Measure its full length and width, then measure each fixing centre from the centre of one screw hole to the centre of the next.

Do not measure from the outside edges of the holes. This can add the diameter of the screw hole to your result and produce an inaccurate comparison.

Also check:

• The distance between the plate and the glazing bead
• The amount of sound timber around each screw hole
• Whether the replacement plate will cover old paint shadows or marks
• Whether the plate can sit flat without touching mouldings or rebates

A replacement plate does not have to use the old holes, but new fixing positions must sit in sound timber and remain clear of the glazing.

How to Measure the Stay Pins

The stay pins, also called pegs or lugs, are normally fixed to the frame or sill beneath the arm. Their position determines how the stay sits when the window is closed and which holes can be used when it is open.

Measure:

• The length and width of each pin plate
• The fixing centres within each plate
• The projection or height of the pin
• The distance between the pin positions
• The available timber around each plate

Do not assume that a new stay arm will work correctly with old pins. The pin diameter, projection and spacing must suit the holes and movement of the replacement stay. Use the compatible pins supplied or specified for the product unless the manufacturer confirms otherwise.

How to Measure a Window Without an Existing Stay

Where no stay is fitted, begin with the clear timber available on the opening casement and the fixed frame below it.

1. Close the window and identify a sound position for the stay’s pivot plate.
2. Measure the clear horizontal space available for the stay arm.
3. Check that the proposed arm position is clear of the glazing bead, frame and other hardware.
4. Identify sound fixing positions for the stay pins below the arm.
5. Open the casement and check how the proposed stay length would move through its full arc.
6. Compare these measurements with the technical drawing for each size under consideration.

Do not scale dimensions from a product photograph displayed on screen. Use the stated measurements or downloadable technical drawing.

A card or paper template cut to the stated overall dimensions can be useful for checking space, but it does not replace testing the pivot and pin relationship.

How to Choose the Right Window Stay Size

There is no single formula that assigns an 8, 10 or 12-inch stay according to window width alone. The correct size depends on the clear fitting space, plate position, required opening positions and the dimensions of the chosen design.

A longer stay needs more uninterrupted space and moves through a wider arc. A shorter stay can be easier to accommodate on a narrow casement, but it may provide a different range of opening positions.

Use this order:

1. Identify the type of stay required.
2. Measure the existing fitting or available space.
3. Compare the full technical drawings for each size.
4. Check the plate, pin and fixing dimensions.
5. Confirm that the stay can move freely through open and closed positions.
6. Choose the style and finish after the functional checks are complete.

If the existing stay operates correctly, replacing it with the same product and size is often the simplest route. Even then, compare the current product drawing because designs and fixing arrangements can differ.

Can You Reuse the Existing Holes and Stay Pins?

Existing screw holes can be reused only when the replacement fixing centres align precisely and the timber still holds the screws firmly.

Do not pull the new fixing plate out of position to make it line up with old holes. This can twist the stay, affect its movement and leave the screws under sideways pressure.

Old pins should only be retained when they are compatible with the replacement arm and correctly positioned. If the new stay is supplied with matching pins, fitting the complete set is normally the safer approach.

Where holes are split, enlarged or no longer secure, repair the timber properly before fitting the replacement. Decorative filler alone is not a suitable structural repair for a loose screw fixing.

Common Window Stay Measuring Mistakes

Using only the named size

An 8, 10 or 12-inch label does not tell you the fixing-plate dimensions, fixing centres, pin size or exact overall length.

Measuring only from end to end

Overall length is useful, but two stays with similar total lengths can have different pivot positions and working-arm dimensions.

Counting the holes

The number of holes is not a reliable way to identify a stay size. Designs can use different hole spacing and configurations.

Ignoring the fixing plates

A stay arm may fit the window while its pivot plate or pins do not fit the available timber.

Assuming the old pins will work

The holes in the new arm must fit over the pins cleanly and without sideways pressure. Similar-looking components are not necessarily compatible.

Choosing by appearance first

Style and finish matter, but they should be selected after the size, plates, pins and movement have been checked.

Window Stay Styles and Sizes

Many traditional peg-style ranges are available in 8, 10 and 12-inch options, including:

• Avon Window Stay
• Monkeytail Window Stay
• Peardrop Window Stay
• Shepherd's Crook Window Stay

These products differ in shape, fixing plates, materials and available finishes. Other stays within the wider collection may use different size options or operating methods, so check the individual product information rather than applying the 8, 10 and 12-inch pattern to every stay.

Related Reading

These supporting guides cover the next steps in choosing, replacing and fitting window hardware:

• Window Furniture Explained
• How to Install Window Stays
• How to Replace Window Hardware

Conclusion

To measure a window stay properly, record the overall length, pivot-to-tip dimension, fixing plate, fixing centres, stay pins and clear space available on the casement.

Do not choose a replacement from the named inch size or appearance alone. Compare the complete product drawing and check that the arm, plates and pins can operate without contacting the frame or glazing.

Once the measurements are confirmed, compare suitable options in our Window Stays Collection.

FAQ

How are window stays measured?

Measure the overall length, the distance from the pivot centre to the tip, the fixing-plate dimensions and fixing centres. You should also measure the stay pins and the clear fitting space on the window.

Is an 8-inch window stay exactly 8 inches long?

Not necessarily from end to end. The named size may refer to the stay arm or another principal dimension, while the decorative end and fixing plate can affect the overall length. Check the product drawing.

How do I choose between an 8, 10 and 12-inch window stay?

Measure the available space and compare the complete technical drawings for each option. The stay must fit the casement, clear surrounding timber and move through useful open and closed positions.

Can I measure a window for a stay if the old fitting is missing?

Yes. Measure the clear timber available for the pivot plate, stay arm and pins, then compare those measurements with the technical drawing. Check the full movement before drilling.

Can I reuse the old screw holes?

Only if the replacement fixing centres align precisely and the timber still provides a firm fixing. Do not distort the new stay to make it fit old holes.

Can I reuse the existing stay pins?

Only when the pins are compatible with the new stay and correctly positioned. If the replacement includes matching pins, using the complete supplied set is normally the safer choice.