A custom range hood should feel like a natural part of your kitchen—not an appliance added after the design is finished. Accurate measurements help ensure the hood fits the space, aligns with the cooktop, accommodates the ventilation insert and achieves the right visual proportions.

Before requesting a quote, you should determine six key measurements:

1. Cooktop or range width

2. Available hood width

3. Distance from the cooking surface to the ceiling

4. Installation clearance above the cooking surface

5. Finished hood height and depth

6. Duct location and size

This guide explains how to collect these measurements for both wall-mount and island range hoods.

Important: The dimensions in this guide are general planning recommendations. Always follow the installation requirements provided by the manufacturers of your cooking appliance and range hood insert, as well as applicable local building and mechanical codes.

Quick Measurement Checklist

Before you begin, prepare the following:

• Tape measure

• Pencil and notepad

• Level or laser level

• Photos of the installation area

• Cooktop or range model number

• Range hood insert model number, if already selected

• Kitchen elevations, cabinet plans or architectural drawings, if available

Record all dimensions in inches and measure each area at least twice.

Understanding the Main Range Hood Measurements

A custom range hood is generally defined by three finished exterior dimensions:

You will also need to confirm the mounting height, ceiling height, insert dimensions and duct position.

Step 1: Identify the Installation Type

Start by determining whether your range hood will be mounted against a wall or above a kitchen island.

Wall-Mount Range Hood

A wall-mount hood is installed against a wall, usually between cabinets or as a freestanding focal point. Measurements must account for:

• Cooktop position

• Cabinet spacing

• Backsplash

• Wall studs

• Ceiling or soffit height

• Duct and electrical locations

Island Range Hood

An island hood is suspended from the ceiling above a cooktop installed in an island. Because there are no surrounding walls or cabinets to help capture cooking fumes, island hoods are commonly designed wider than the cooking surface.

Island installations also require careful confirmation of:

• Cooktop centerline

• Ceiling structure

• Hood suspension points

• Duct direction

• Finished ceiling height

• Position of lighting and decorative ceiling features

Image recommendation: Insert a side-by-side diagram labeled “Wall-Mount Hood” and “Island Hood.”

Step 2: Measure the Cooktop or Range Width

Measure the cooking appliance from its left edge to its right edge. Use the actual appliance width rather than relying only on the nominal product size.

For example, an appliance sold as a 36-inch range may have a slightly different actual width. Check the appliance specifications or installation manual before confirming the hood size.

Record:

• Manufacturer

• Model number

• Actual width

• Fuel type: gas, electric or induction

• Number and type of burners

• Total heat output, if available

How Wide Should the Range Hood Be?

For a wall-mount installation, the hood should generally be at least as wide as the cooking surface. When space allows, extending the hood approximately 3 inches beyond each side can improve coverage and create a more substantial appearance.

For an island installation, a hood that is approximately 3 to 6 inches wider than the cooktop is commonly preferred because cooking fumes can spread in every direction.

These are planning ranges rather than universal requirements. Cabinet spacing, cooking style, insert capacity and the appliance manufacturer’s instructions must also be considered.

Step 3: Measure the Available Width

Next, measure the full space where the hood will be installed.

For a hood positioned between wall cabinets, measure the opening:

• At the bottom

• At the middle

• Near the ceiling

Walls and cabinets are not always perfectly square. Use the smallest measurement when determining whether the hood will fit.

Also check for:

• Cabinet doors that may swing toward the hood

• Crown molding

• Shelves

• Windows

• Tile edges

• Decorative wall panels

• Uneven walls

• Nearby light fixtures

Do not assume that a 36-inch opening will comfortably accommodate a hood with an exact finished width of 36 inches. Depending on the installation method, a small tolerance may be necessary. Review this with your contractor and the hood designer before production.

Step 4: Determine the Installation Height Above the Cooktop

Measure vertically from the top of the cooking surface—not from the floor or the top of the range controls—to the planned bottom edge of the hood.

This distance is called the mounting clearance.

Clearance requirements vary according to:

• Gas, electric or induction cooking

• Heat output

• Range hood insert specifications

• Hood depth

• Hood material

• Local requirements

• Appliance manufacturer instructions

Many residential hoods are installed within a general range of approximately 24 to 36 inches above the cooking surface. However, this should not be treated as a fixed rule.

Some appliance and insert manufacturers require a greater minimum clearance, especially above high-output gas ranges. A hood installed too low may create a safety concern or interfere with cooking. A hood installed too high may capture smoke, steam and grease less effectively.

Before confirming this measurement:

1. Read the range or cooktop installation manual.

2. Read the range hood insert installation manual.

3. Use the greater minimum clearance when the requirements differ.

4. Ask your contractor to verify applicable local codes.

Write down the final planned clearance as Measurement A.

Image recommendation: Show a vertical arrow from the cooking surface to the bottom of the hood labeled “Mounting Clearance.”

Step 5: Measure the Ceiling Height

Measure vertically from the finished floor to the finished ceiling directly above the cooking appliance.

Do not rely only on the ceiling height listed in the building plans. Finished flooring, ceiling treatments and structural variations can change the final measurement.

Measure the ceiling at several points, especially if the kitchen has:

• A sloped or vaulted ceiling

• Beams

• A soffit

• A tray ceiling

• Decorative molding

• Different ceiling levels

• A ceiling-mounted island hood

Record the finished ceiling height as Measurement B.

Then measure the height from the finished floor to the top of the cooking surface. Most countertops are near a standard height, but the actual measurement should always be used. Record this as Measurement C.

Step 6: Calculate the Finished Hood Height

If the custom hood will extend from its lower edge to the ceiling, use this formula:

Finished Hood Height = Ceiling Height − Cooking Surface Height − Mounting Clearance

Example

Assume:

• Finished ceiling height: 108"

• Cooking surface height: 36"

• Planned clearance above the cooktop: 30"

The calculation is:

108" − 36" − 30" = 42"

The approximate finished hood height would therefore be 42 inches.

This calculation provides the total available vertical space. Decorative crowns, chimneys, molding and installation tolerances must still be considered before the final shop drawings are approved.

If the Hood Does Not Reach the Ceiling

Some custom hoods terminate below the ceiling or connect to a separate chimney section. In this situation, decide where the finished top of the hood should end and measure from that point to the planned bottom edge.

Also confirm how the ductwork will be concealed above the hood.

Image recommendation: Include a full-height wall diagram identifying ceiling height, cooking surface height, mounting clearance and hood height.

Step 7: Determine the Hood Depth

Hood depth affects both ventilation performance and the overall proportions of the kitchen.

Measure from the wall to the front edge of the cooking surface. Then note the full front-to-back depth of the range or cooktop.

Custom wall-mount hoods are commonly designed with depths such as 21, 22, 24 or 27 inches, depending on the appliance and hood style. The best depth depends on:

• Cooking surface depth

• Burner position

• Hood mounting height

• Insert dimensions

• Desired coverage

• Head clearance

• Cabinet depth

• Decorative hood shape

A deeper hood can provide more coverage, but it may feel visually heavy or interfere with sightlines if mounted too low. A shallow hood may look streamlined but provide less capture over the front burners.

Island hoods generally require more generous coverage because there is no rear wall to help contain rising fumes.

Do not select the exterior depth until the range hood insert has been reviewed. The hood must have enough interior space for the insert, support structure, duct connection and electrical components.

Step 8: Locate the Centerline

The range hood should normally be centered over the cooking surface.

To establish the centerline:

1. Measure the complete width of the cooktop.

2. Divide that measurement by two.

3. Mark the center of the appliance.

4. Extend a vertical reference line toward the ceiling using a level or laser.

For a wall-mount hood, record the centerline’s distance from a fixed reference point, such as a side wall or cabinet.

For an island hood, record the centerline from at least two fixed directions. For example:

• Distance from the nearest wall

• Distance from the end of the island

• Distance from the surrounding cabinets

Using two reference measurements makes it easier for the designer and installer to verify the hood position.

If the cooktop, cabinetry and duct opening do not share the same centerline, notify the hood designer before production. Do not assume a custom hood can automatically correct a major alignment issue.

Step 9: Measure the Duct Location and Size

A custom decorative hood is only one part of the ventilation system. The insert, ductwork and exterior termination must also work together.

Record:

• Duct diameter or rectangular dimensions

• Center of the duct opening

• Distance from the wall

• Distance from the cooktop centerline

• Venting direction

• Ceiling or wall exit location

• Existing elbows or transitions

• Available space above the ceiling

Common insert duct connections may include 6-inch or 8-inch round ducts, but the required duct size depends on the selected insert. Never reduce the duct below the insert manufacturer’s requirement unless the manufacturer specifically permits it.

Unnecessary bends, long duct runs and abrupt transitions can reduce actual airflow and increase noise. The duct plan should be reviewed by a qualified HVAC professional or contractor.

If the ductwork has not yet been installed, it is usually best to finalize the insert and hood design before cutting the ceiling or wall opening.

Step 10: Confirm the Range Hood Insert

The insert is the functional ventilation unit installed inside the decorative hood. Its dimensions directly affect the hood’s exterior size and internal construction.

Before approving the custom hood, confirm:

• Insert brand and model

• Overall insert width

• Cutout dimensions

• Insert depth and height

• Airflow capacity

• Duct size and discharge direction

• Electrical requirements

• Required clearances

• Service access

• Filter removal direction

Nauxus offers range hood inserts in multiple sizes and airflow configurations. If you plan to use an insert from another manufacturer, send the complete specification sheet and installation manual with your quote request.

Do not provide only the advertised insert width. The exterior dimensions, cutout size and mounting requirements may all be different.

Measuring a Wall-Mount Range Hood

For a wall-mount custom hood, provide:

• Cooktop width and depth

• Hood width, height and depth

• Cooking surface height

• Mounting clearance

• Finished ceiling height

• Distance between adjoining cabinets

• Hood centerline

• Duct size and location

• Backsplash height

• Crown molding or soffit dimensions

• Insert model

• Front and side photographs

Check whether the wall contains adequate structural support. Heavy handcrafted metal hoods may require blocking or reinforcement behind the finished wall.

Measuring an Island Range Hood

For an island hood, provide:

• Cooktop width and depth

• Island dimensions

• Hood width, height and depth

• Cooking surface height

• Mounting clearance

• Finished ceiling height

• Hood centerline in two directions

• Duct size and location

• Ceiling slope, beams or soffits

• Insert model

• Ceiling construction and support information

• Photos from all four sides

Island hoods require secure ceiling support. The decorative hood should not be supported by ductwork alone.

If the ceiling is sloped or vaulted, provide the ceiling angle and the height at both sides of the planned hood location. Custom transition pieces or mounting structures may be required.

Common Range Hood Measuring Mistakes

Measuring From the Floor Instead of the Cooking Surface

Mounting clearance is measured from the top of the cooking surface to the bottom of the hood.

Ordering the Hood Before Choosing the Insert

The insert determines the required internal opening, ventilation space and duct connection. Selecting it after the hood is built can result in costly modifications.

Using Only the Nominal Appliance Width

Always verify the actual appliance dimensions in the manufacturer’s specification sheet.

Ignoring Crown Molding and Ceiling Details

Crown molding, beams and soffits can change the available hood height and top profile.

Assuming the Duct Is Centered

Existing duct openings are often offset. Measure their exact position rather than assuming they align with the cooktop.

Forgetting the Front Burners

A hood may match the cooktop width but still be too shallow to cover the front cooking area effectively.

Measuring an Unfinished Room Without Accounting for Finishes

Flooring, backsplash tile, drywall and ceiling finishes can change the final dimensions. Clearly identify whether each measurement was taken before or after finishes were installed.

Not Checking the Appliance Manuals

The cooking appliance and insert manuals may specify different minimum clearances. Both must be reviewed before the hood height is finalized.

What to Send With Your Custom Range Hood Request

To help the design team evaluate your project, submit:

• Desired hood width, height and depth

• Finished ceiling height

• Cooking surface height

• Planned mounting clearance

• Range or cooktop model number

• Insert model number

• Duct dimensions and location

• Wall-mount or island installation

• Front and side photos of the space

• Cabinet elevations or architectural drawings

• Inspiration photos

• Preferred material and finish

• Preferred hood shape

• Crown, strap, rivet and apron preferences

• Project ZIP code

• Target installation date

If construction has not yet started, drawings and appliance specifications can be used for the preliminary design. Final field measurements should still be confirmed before production.