Router Bit Depth Calculator

Professional router bit depth calculator for precision woodworking. Calculate optimal cutting depths, feed rates, router speeds, and safety parameters for various router bits and materials.

Depth Analysis Speed Control Feed Rates Safety Guide

⚠️ ROUTER SAFETY NOTICE

Always use proper safety equipment when operating routers. Follow manufacturer guidelines for bit speeds and depths. Never exceed recommended cutting depths or feed rates. Secure workpiece properly before routing.

Router Specifications

Router Bit Type

Bit Specifications

Bit Diameter

Cutting Length

Number of Flutes

Bit Material

Material & Cut Parameters

Material Type

Material Thickness

Desired Cut Depth

Cut Type

Router Settings

Router Power

Router Speed

RPM

Feed Rate

Number of Passes

Routing Analysis

Enter router bit specifications and cutting parameters to calculate optimal depths, speeds, and safety guidelines for your routing operation.

Router Bit Depth & Speed Guide

Cutting Depth Optimization

Proper cutting depth prevents router bit damage, ensures safety, and produces quality results. Use our router bit depth calculator for precise depth recommendations. 78% of router bit failures result from excessive cutting depth in single passes.

Maximum Safe Cutting Depths by Bit Diameter

Bit Diameter	Softwood (Pine)	Hardwood (Oak)	Plywood/MDF	Recommended Passes
1/4" (6mm)	1/8" max	1/16" max	3/32" max	Multiple shallow
3/8" (10mm)	3/16" max	1/8" max	5/32" max	2-3 passes
1/2" (12mm)	1/4" max	3/16" max	3/16" max	2 passes typical
3/4" (19mm)	3/8" max	1/4" max	5/16" max	1-2 passes
1" (25mm)+	1/2" max	3/8" max	7/16" max	Single pass OK

Pro Tips: Safe Routing Depths

Rule of Half: Never cut deeper than half the bit diameter in one pass - reduces vibration by 65%
Material Matters: Hardwoods require 30-40% shallower cuts than softwoods at same speed
Listen to Router: Laboring sound indicates too deep/fast - reduce depth or feed rate immediately
Final Pass Light: Leave 1/32" for final cleanup pass - improves surface finish significantly
Climb Cut Caution: Reduce depth 50% when climb cutting - increased kickback risk

Router Speed & RPM Guidelines

Bit diameter determines optimal router speed. Larger bits must run slower to prevent overheating and dangerous rim speeds. Calculate safe speeds with our calculator.

Recommended Router Speeds by Bit Diameter

Bit Diameter	Optimal RPM	Maximum RPM	Rim Speed (FPM)	Common Applications
Up to 1"	20,000-24,000	24,000	6,280	Small trim, edging
1" to 2"	16,000-18,000	20,000	9,420	Profile bits, dados
2" to 2.5"	12,000-16,000	16,000	10,470	Panel raising, large profiles
2.5" to 3.5"	8,000-12,000	12,000	11,000	Raised panels, door making
Over 3.5"	6,000-8,000	8,000	9,420	Large panel bits (table only)

Case Study: Panel Raising Bit Setup

Project: Raised panel doors, 3.5" vertical panel raising bit, oak

Bit Specifications:

Bit Diameter: 3.5" (89mm)
Cutting Height: 3/4"
Shank: 1/2"
Material: Oak hardwood (3/4" thick)

Safe Operating Parameters:

Router Speed: 10,000 RPM (reduced from 18,000)
Rim Speed: 9,160 FPM (safe range)
Feed Rate: 15-20 IPM (slow, controlled)
Depth per Pass: 1/8" maximum
Total Passes: 6 passes @ 1/8" each

Safety Results:

No burning or scorch marks
Smooth surface requiring minimal sanding
Router operated quietly without laboring
Total routing time: 3 minutes per panel (safe pace)

Critical Safety Note: Running this 3.5" bit at full speed (24,000 RPM) would create 21,200 FPM rim speed - dangerously exceeding 12,000 FPM safety limit. Always reduce speed for large bits!

Frequently Asked Questions

Safe cutting depth varies by bit size and material hardness. Use our router bit depth calculator for precise recommendations.

Rule of Half: Never exceed 50% of bit diameter in one pass - 78% of bit failures result from excessive depth.

Maximum Depths by Bit Diameter:

1/4" bit: 1/8" max in hardwood, 3/32" in softwood
1/2" bit: 1/4" max in hardwood, 3/16" in softwood
3/4" bit: 3/8" max in hardwood, 1/4" in softwood
1" bit: 1/2" max (multiple passes for deeper cuts)

Material Impact: Hardwoods require 30-40% shallower cuts than softwoods. MDF/plywood fall between.

Bit diameter determines safe router speed. Larger bits must run slower to prevent dangerous rim speeds. Calculate with our calculator.

Speed Guidelines by Bit Diameter:

Up to 1": 20,000-24,000 RPM (safe for small trim work)
1" to 2": 16,000-18,000 RPM (profile bits, dados)
2" to 2.5": 12,000-16,000 RPM (panel raising)
2.5" to 3.5": 8,000-12,000 RPM (large profiles)
Over 3.5": 6,000-8,000 RPM (table-mounted only)

Rim Speed Safety: Rim speed should not exceed 12,000 FPM. A 3.5" bit at 24,000 RPM creates dangerous 21,200 FPM - reduce to 10,000 RPM for safe 9,160 FPM.

Feed rate affects cut quality and safety. Too fast causes tear-out, too slow causes burning. Adjust based on material and bit size.

Feed Rates by Material:

Hardwoods (Oak, Maple): 40-80 IPM - denser grain requires slower feed
Softwoods (Pine, Cedar): 60-120 IPM - faster acceptable
Plywood: 50-100 IPM - consistent density
MDF: 80-150 IPM - uniform material, faster possible
Hardboard: 60-100 IPM - abrasive, reduces bit life

Adjustment Factors:

Reduce 30-50% for climb cutting (increased kickback risk)
Reduce 25% for deep cuts (>1/4" depth)
Increase 20-30% for final light passes

Sound Test: Smooth, consistent sound = correct rate. Laboring/straining = too fast. High-pitched squeal = too slow (burning).

For cuts deeper than 1/4", use multiple passes. Divide the total depth by the maximum safe depth per pass. For example, a 3/4" deep cut with a 1/2" bit should be made in 3-4 passes of about 1/4" each.

Burning is caused by excessive heat from slow feed rates, dull bits, or wrong speeds. Prevent by using sharp bits, proper speeds, adequate feed rates, and taking lighter cuts. Keep bits clean and properly maintained.

Conventional cutting (against bit rotation) is safer and standard for handheld routers. Climb cutting (with bit rotation) can provide better finish but requires more control and is typically used with router tables or CNC machines.