How to Measure Crib Screws Correctly

Updated December 17, 2025 by Jan of Unique Baby Gear Ideas

If you need replacements, you need to know how to measure crib screws correctly. This is important for parents and grandparents trying to reassemble a crib that has a few pieces of missing hardware. When a screw is even slightly off in length or thread size, it may not seat properly, which can lead to frustration, parts that won’t line up, or a crib that just doesn’t feel right once assembled.

How to measure crib screws correctly is one of the most common questions I hear from parents and grandparents trying to reassemble a crib with missing hardware. When a screw is even slightly off in length or thread size, it may not seat properly, which can lead to frustration, parts that won’t line up, or a crib that just doesn’t feel right once assembled.

The good news is that you do not need special tools or technical experience to get accurate measurements. With a ruler, careful observation, and a step-by-step approach, you can identify the exact crib screw size you need before ordering replacement hardware or contacting the manufacturer.

Why Measuring Crib Screws Correctly Matters

Crib hardware is designed as a matched system. Screws, bolts, barrel nuts, and brackets are engineered to work together, often within very tight tolerances. A screw that is too short may not fully engage the threads, while one that is too long can bottom out before tightening.

This is especially important for older cribs, discontinued models, or vintage cribs where original hardware kits are no longer available. Accurate measurements reduce guesswork and help prevent repeated purchases of hardware that almost fits — but not quite.

Tools You Need to Measure Crib Screws

You can measure crib screws using simple household tools:

• A ruler with millimeter markings
• A tape measure for reference
• A flat surface and good lighting
• The original screw, if available

If the screw is missing, you can still measure the receiving hole, barrel nut, or matching hardware from another side of the crib.

How to Measure Crib Screws Correctly (Step-by-Step)

Step 1: Measure the Screw Length

Screw length is measured from the underside of the head to the very tip of the threads. Do not include the head itself in this measurement.

Lay the screw flat against a ruler and align the bottom of the head with the zero mark. Most crib screws range between 30 mm and 80 mm, depending on the crib design and connection point.

Step 2: Measure the Diameter

The diameter is the thickness of the threaded portion of the screw. This measurement is usually metric for crib hardware.

Place the screw across the ruler and measure the widest part of the threads. Common crib screw sizes include M6 (approximately 6 mm) and M8 (approximately 8 mm).

Step 3: Identify the Thread Type

Most modern cribs use metric threads rather than standard (SAE) threads. Metric screws will thread smoothly into metric barrel nuts or inserts without resistance.

If a screw binds, wobbles, or requires force, stop. Mixing metric and standard screws can damage crib hardware.

Step 4: Check the Head Style

Crib screws are designed with specific head styles to sit flush with brackets or rails. Common head styles include:

• Allen (hex) head
• Phillips head
• Flat (countersunk) head
• Button head

Always match the original head style when possible. A mismatched head can prevent rails from tightening properly.

Visual Reference: Measuring a Crib Screw

Go here to see more

This visual shows how to measure the screw length from the underside of the head and how to identify diameter using simple tools. Having a visual reference can help confirm that your measurements are accurate before ordering replacements.

Common Measurement Mistakes to Avoid

• Including the screw head in length measurements
• Guessing thread type by appearance alone
• Using screws that are “close enough”
• Mixing metric and standard hardware

Even small differences can prevent proper alignment, especially at crib corner joints where multiple parts meet.

When the Original Screw Is Missing

If the original screw is lost, remove a matching screw from another side of the crib and measure that instead. This is the most reliable method when only one or two screws are missing.

If all screws are missing, locate the crib’s manufacturer label and model number. This information allows you to search for original specifications or compatible replacement kits.

Related Crib Hardware Help

If measuring still leaves you unsure, these guides may help clarify next steps:

• Are Crib Screws Universal?
• Crib Screws Missing? What to Do
• Crib Parts & Replacement Hardware Hub

Additional Safety Reference

For recall and safety information related to crib hardware, you can also review guidance from the U.S. Consumer Product Safety Commission .

Final Thoughts

Learning how to measure crib screws correctly takes only a few minutes, but it can save hours of frustration and repeated hardware orders. Accurate measurements help ensure parts align properly and that crib components tighten as intended.

If you’re unsure after measuring, pause and verify before forcing a screw that doesn’t fit. Careful measuring is the simplest step toward a smooth crib reassembly.

Crib hardware disclaimer: I am not a crib manufacturer or repair service. This information is provided for general identification and planning purposes only. Always follow the crib manufacturer’s instructions and discontinue use of a crib if hardware cannot be securely installed.

Hi, I’m Jan — the creator of Unique Baby Gear Ideas. I love helping expecting parents discover nursery décor inspiration and creative photo shoot ideas that make every stage of pregnancy feel beautiful.

Over the years, I’ve helped thousands of parents choose safe, stylish nursery furniture through hands-on reviews and real-world testing.

The suggestions I share here come from years of hands-on experience styling nurseries, reviewing maternity gowns, and learning what makes each photo session shine.

All articles and images on Unique Baby Gear Ideas are personally reviewed and edited by Jan Bay. Modern creative tools may assist with design or drafting, but every final page reflects my own voice, experience, and editorial judgment.