How do I measure for a range hood if my cooktop is against a wall?

Measure the distance from the wall to the front edge of the cooktop to get the depth. For width, measure from the left side wall to the right side wall, then subtract any clearances required by the hood, usually 1 to 3 inches per side. The hood width should match or slightly exceed the cooktop width, but you must stay within the available wall space. Also measure the distance from the cooktop to the wall above, as this may affect the mounting height.

What is the minimum height for a range hood above a gas cooktop?

The minimum clearance is typically 24 inches from the cooktop surface to the hood's bottom edge, but this can vary by manufacturer and local codes. Some gas cooktops allow 18 inches if the hood is listed for that clearance. Always check the hood's installation manual for the specific minimum, and never go below it. For electric cooktops, the minimum is usually 18 inches, but again, verify the manual.

Should I buy a range hood that is wider than my cooktop?

Yes, a hood that is 6 inches wider than the cooktop is often recommended for better capture of smoke and heat. For example, a 30-inch cooktop pairs well with a 36-inch hood. However, you must ensure the wider hood fits within your available wall or cabinet space. If space is limited, a hood that matches the cooktop width is acceptable, but performance may be slightly lower on the outer burners.

How do I measure for a ducted range hood if I have an existing duct?

Measure the diameter of the existing duct, usually 6 or 8 inches, and the total length of the duct run from the hood location to the outside vent. Include all straight sections and add 5 feet for every 90-degree bend and 2.5 feet for each 45-degree bend. This total helps you determine the required CFM. Also measure the height from the cooktop to the duct collar, as this affects the hood's mounting height and the length of the duct connector needed.

How to Measure for a Range Hood: A Step-by-Step Width and Height Guide

What Do You Actually Need to Measure?

Before you pick up a tape measure, understand the three key dimensions: width, height, and duct run. Width is the horizontal span of the hood's underside, typically 24, 30, 36, or 48 inches. Height refers to the vertical distance from the cooktop surface to the hood's bottom edge, which is often called the mounting height. Duct run is the length of the vent pipe from the hood to the outside wall or roof.

You also need the depth of the hood, which is the front-to-back measurement. Depth usually matches the cooktop's depth, but it can be slightly less. Finally, note the clearance from the side walls or cabinets, because some hoods require additional space for proper airflow and service access. Write down all measurements in inches and keep them handy when comparing models.

Having these numbers ready prevents the most common installation mistakes: buying a hood that is too narrow for the cooktop, mounting it too high for effective capture, or discovering that the duct path has too many bends. Measure twice, but also measure at the right points, which the next sections explain.

Step 1: Measure the Cooktop Width (The Starting Point)

The width of the range hood should be at least equal to the width of the cooktop, and ideally a few inches wider. For example, if you have a 30-inch cooktop, a 30-inch hood is the minimum, but a 36-inch hood offers better capture of smoke and steam from side burners. Measure the cooktop's width from left to right across the outermost edges of the cooking surface, not the countertop.

Use a steel tape measure for accuracy. Place the hook at the left edge of the cooktop and extend it to the right edge. Record this number. If you have a freestanding range, measure the range's top surface width, not the oven body. For wall ovens with a separate cooktop, measure only the cooktop unit.

If your cooktop is not rectangular, such as a round or oval induction unit, measure the widest point in both directions. The hood width should still match or exceed that maximum width. This step is the foundation for all other measurements, so take it slowly and double-check.

Step 2: Determine the Hood Width (Match or Exceed Cooktop)

Once you have the cooktop width, decide on the hood width. Industry guidelines recommend that the hood be the same width as the cooktop or up to 6 inches wider. For example, a 36-inch cooktop pairs well with a 36-inch or 42-inch hood. A wider hood does not look odd if the space allows; it simply improves performance by capturing rising heat and grease more effectively.

Measure the available space between side walls or upper cabinets. If the cooktop is centered in a 60-inch base cabinet run, you have plenty of room for a 42-inch hood. But if the cooktop sits close to a wall on one side, a wider hood may not fit. Subtract the clearances required by the hood manufacturer, usually 1 to 3 inches on each side, from the total available width.

Also consider the duct transition. The hood's internal blower or duct collar is usually centered, but some models have offset connections. Measure the hood's width at the outer edge, not the blower housing. When in doubt, choose a model that matches the cooktop width exactly, as this is the most common and safest choice for both fit and ventilation performance.

Step 3: Measure the Mounting Height (From Cooktop to Hood)

The mounting height is the vertical distance from the cooktop surface to the bottom edge of the hood. This measurement is critical for both performance and safety. For gas cooktops, the typical clearance is 24 to 30 inches. For electric cooktops, it is 18 to 24 inches. These ranges come from manufacturer specs and building codes, so always check the specific hood's manual.

To measure, place a straight edge or a level across the top of the cooktop. Then use a tape measure to find the distance from that straight edge up to the underside of the cabinet or wall where the hood will attach. Mark this height on the wall with a pencil. The hood's bottom edge should sit at this mark, not the top of the hood body.

If you have a tall cooktop or a raised counter, adjust accordingly. A hood mounted too high loses capture efficiency, while one mounted too low can be a head hazard and may violate clearance codes. Measure at the front and back of the cooktop to ensure the hood is level. Record the height in inches, as most hoods have adjustable mounting brackets that allow some range.

Step 4: Measure the Depth and Duct Run (For Proper Fit and Venting)

Depth is the front-to-back measurement of the hood's underside. Standard depths are 18 to 24 inches, but they should be close to the cooktop's depth, typically 20 to 22 inches. Place a tape measure from the back wall to the front edge of the cooktop. The hood's depth should be at least as much as the cooktop's depth to capture rising grease and steam effectively.

For the duct run, measure the distance from the hood's top or back to the outside vent termination. Include all horizontal runs and vertical rises. Count every 90-degree bend as 5 feet of duct length and every 45-degree bend as 2.5 feet, because bends restrict airflow. This estimated total helps you compare hoods with different CFM ratings, but for the actual installation, you will need to know the exact path.

Measure the diameter of the duct collar on the hood, usually 6 or 8 inches. The ductwork must match this size. If you are using a recirculating hood with a charcoal filter, you do not need a duct run, but you still need to measure the distance to the nearest power outlet and the space for the filter. Write down all these numbers, including the total duct length and the number of bends, because they affect the hood's performance and installation complexity.