Feeds & Speeds
RPM, feed rate, chip load, cutting speed, SFM, MRR and spindle calculations.
View CalculatorsTHE TRUE MACHINISTS
Machining Calculators, Tools & Reference
The True Machinists brings machining calculators, resources and tools together so machinists, engineers and programmers can find the number or reference they need quickly.
Popular: Feed & Speed Calculator Chip Load RPM SFM
CALCULATOR LIBRARY
Find a Calculator
Choose the machining process or calculation type that matches the job.
Milling
End mills, stepover, stepdown, engagement, surface finish and milling calculations.
View CalculatorsTurning
Turning speed, feed, depth of cut, cycle time and parting calculations.
View CalculatorsDrilling
Drill RPM, feed, hole size, peck drilling and drill point calculations.
View CalculatorsThreading
Tap drill size, pitch, thread depth, TPI and clearance calculations.
View CalculatorsGeometry
Bolt circles, angles, arcs, radii, triangles and shop geometry.
View CalculatorsManufacturing
Cycle time, machining cost, production rate and manufacturing calculations.
View CalculatorsMaterials
Material weight, volume, density and stock calculations.
View CalculatorsConverters
Length, speed, feed, thread and engineering unit conversions.
View CalculatorsEVERYDAY CALCULATIONS
Common Machining Calculations
Quick access to the numbers used most often at the machine and in the programming office.
Angle Calculator
Calculate an angle from opposite and adjacent dimensions.
Open CalculatorArc Length Calculator
Calculate arc length from radius and included angle.
Open CalculatorBolt Circle Calculator
Calculate bolt hole coordinates around a circular bolt pattern.
Open CalculatorChip Load Calculator
Calculate chip load per tooth from feed rate, RPM and flute count.
Open CalculatorCircle Calculator
Calculate circumference and area from circle diameter.
Open CalculatorClearance Hole Calculator
Calculate a simple clearance hole size from nominal fastener diameter and clearance allowance.
Open CalculatorCNC Cost Calculator
Estimate CNC production cost from machine rate, labor rate, cycle time and quantity.
Open CalculatorCNC Cycle Time Calculator
Estimate machining time from total toolpath length and feed rate.
Open CalculatorCNC Facing Time Calculator
Estimate facing time from radial travel, feed per revolution and spindle speed.
Open CalculatorCNC Feed Rate Calculator
Calculate milling feed rate from spindle speed, number of flutes and chip load.
Open CalculatorCNC Feeds & Speeds Calculator
Calculate spindle speed and feed rate from cutting speed, tool diameter, chip load and flute count.
Open CalculatorCNC Ramp Angle Calculator
Calculate ramp angle from ramp depth and horizontal ramp distance.
Open CalculatorCNC Spindle Speed Calculator
Calculate spindle speed from cutting speed and tool diameter.
Open CalculatorCNC Turning Feed Calculator
Calculate turning feed rate from RPM and feed per revolution.
Open CalculatorCNC Turning Speed Calculator
Calculate spindle RPM from turning surface speed and workpiece diameter.
Open CalculatorCoordinate Distance Calculator
Calculate straight-line distance between two XY coordinates.
Open CalculatorCutting Speed Calculator
Calculate cutting speed from spindle RPM and tool diameter.
Open CalculatorDecimal to Fraction Converter
Convert a decimal inch value to the nearest common 1/64 inch fraction.
Open CalculatorDegrees to Radians Converter
Convert angles between degrees and radians.
Open CalculatorDrill Feed & Speed Calculator
Calculate drill RPM and feed rate from cutting speed, drill diameter and feed per revolution.
Open CalculatorDrill Feed Calculator
Calculate drill feed rate from RPM and feed per revolution.
Open CalculatorDrill Point Depth Calculator
Estimate drill point depth from diameter and included angle.
Open CalculatorDrill RPM Calculator
Calculate drill spindle speed from cutting speed and drill diameter.
Open CalculatorEnd Mill Calculator
Calculate basic end mill spindle speed and feed rate from cutting speed, diameter and chip load.
Open CalculatorFeed Per Revolution Calculator
Calculate feed per revolution from feed rate and spindle speed.
Open CalculatorFeed Per Tooth Calculator
Calculate feed per tooth from table feed, RPM and flute count.
Open CalculatorHelical Milling Calculator
Calculate axial step per revolution from total depth and number of revolutions.
Open CalculatorHole Depth Calculator
Calculate effective hole depth from total programmed depth and point allowance.
Open CalculatorInch to Millimeter Converter
Convert inch measurements to millimeters and back.
Open CalculatorIPM to mm/min Converter
Convert feed rate between inches per minute and millimetres per minute.
Open CalculatorMachining Cost Calculator
Estimate machining cost from machine rate, cycle time and setup cost.
Open CalculatorMachining Time Calculator
Calculate time from travel distance and feed rate.
Open CalculatorManufacturing Break-Even Calculator
Calculate the quantity needed to recover fixed setup costs from contribution margin.
Open CalculatorMaterial Cost Calculator
Estimate material cost from weight and price per unit mass.
Open CalculatorMaterial Density Calculator
Calculate density from mass and volume.
Open CalculatorMaterial Removal Rate Calculator
Calculate milling material removal rate from width of cut, depth of cut and feed rate.
Open CalculatorMaterial Volume Calculator
Calculate material volume from weight and density.
Open CalculatorMaterial Weight Calculator
Calculate material weight from volume and density.
Open CalculatorMilling Feeds & Speeds Calculator
Calculate milling RPM and feed rate from cutting speed, tool diameter, flute count and chip load.
Open CalculatorMilling Stepdown Calculator
Calculate a stepdown from cutter diameter and the selected percentage of diameter.
Open CalculatorMilling Stepover Calculator
Calculate stepover from tool diameter and the desired percentage of cutter width.
Open CalculatorMilling Surface Finish Calculator
Estimate theoretical cusp height from ball end mill diameter and stepover.
Open CalculatorParting Cut Feed Calculator
Calculate parting feed rate from spindle speed and feed per revolution.
Open CalculatorPeck Drilling Calculator
Calculate a simple peck depth from drill diameter and selected multiplier.
Open CalculatorPitch to TPI Calculator
Convert metric thread pitch to threads per inch.
Open CalculatorPlunge Rate Calculator
Calculate plunge feed from RPM, flute count and chip load.
Open CalculatorProduction Rate Calculator
Calculate parts per hour from cycle time.
Open CalculatorRadius & Diameter Calculator
Convert between radius and diameter.
Open CalculatorRight Triangle Calculator
Calculate a missing side of a right triangle from the other two sides.
Open CalculatorSFM Calculator
Calculate surface feet per minute from spindle speed and tool diameter.
Open CalculatorSFM to m/min Converter
Convert surface speed between SFM and metres per minute.
Open CalculatorSine Bar Calculator
Calculate sine bar setup height from angle and bar length.
Open CalculatorSlot Milling Calculator
Calculate basic slotting MRR from tool diameter and feed rate.
Open CalculatorSpindle Power Calculator
Estimate spindle power from cutting force and cutting speed.
Open CalculatorStock Weight Calculator
Estimate weight of rectangular stock from dimensions and density.
Open CalculatorTap Drill Size Calculator
Calculate a basic metric tap drill size from nominal diameter and pitch.
Open CalculatorThread Depth Calculator
Calculate basic metric external thread radial depth from pitch.
Open CalculatorThread Major Diameter Calculator
Calculate major diameter from nominal size and tolerance allowance.
Open CalculatorThread Percentage Calculator
Calculate thread percentage from actual thread height and theoretical thread height.
Open CalculatorTool Deflection Calculator
Estimate cantilever tool deflection from force, length, diameter and modulus.
Open CalculatorTool Engagement Calculator
Calculate radial engagement as a percentage of cutter diameter.
Open CalculatorTool Life Calculator
Estimate tool life from a baseline tool life, baseline speed and speed exponent.
Open CalculatorTPI to Pitch Calculator
Convert threads per inch to metric thread pitch.
Open CalculatorTurning Cycle Time Calculator
Estimate straight turning cutting time from travel length and feed rate.
Open CalculatorTurning Depth of Cut Calculator
Calculate radial depth of cut from starting and finished diameters.
Open CalculatorTurning Material Removal Rate Calculator
Calculate a simplified turning MRR from starting diameter, depth of cut, feed and spindle speed.
Open CalculatorFEEDS & SPEEDS
Set the cutting numbers first.
Calculate spindle speed, feed rate, chip load, surface speed and material removal before moving from the formula to the machine.
Use results as a starting value.
Check tool maker data, machine limits, material and actual cutting conditions before production.
Open Feed & Speed →REFERENCE
Machining Reference
Keep dimensions, formulas, unit conversions and material information close to the calculation.
REFERENCE
Thread Charts
Metric and inch thread reference information.
Open ReferenceREFERENCE
Drill Charts
Metric, fractional, letter and number drill references.
Open ReferenceREFERENCE
Machining Formulas
Core relationships used across feeds, speeds and shop math.
Open ReferenceREFERENCE
Unit Conversions
Common inch, metric, speed, feed and angle conversions.
Open ReferenceREFERENCE
Material Density
Approximate density values for common engineering materials.
Open ReferenceREFERENCE
Tooling Basics
Practical cutting tool terminology and setup notes.
Open ReferenceMATERIALS
Material Reference
Common materials with practical machining notes and related calculations.
Aluminum
Lightweight engineering metal with broad CNC machining use.
View Material →Brass
Common non-ferrous machining material with a wide range of grades.
View Material →Cast Iron
Machining material with varied grades and abrasive wear behavior.
View Material →Copper
High-conductivity metal used for electrical and thermal components.
View Material →Engineering Plastics
Acetal, nylon and other plastics with very different cutting behavior from metals.
View Material →Mild Steel
Low-carbon steel used widely for general machining and fabrication.
View Material →GUIDES & NOTES
Practical Machining Information
Technical explanations behind the numbers and processes used every day.
CNC Milling Basics
A practical overview of tools, workholding and cutting parameters.
Read Guide →CNC Turning Basics
Key relationships between diameter, surface speed, feed and depth of cut.
Read Guide →Cutting Tool Basics
A concise reference for end mills, drills, turning tools and tool geometry.
Read Guide →Drilling Feed & Speed Basics
The core inputs used when drilling holes.
Read Guide →How Tap Drill Size Is Calculated
Understand the simple metric tap drill relationship.
Read Guide →How to Calculate Chip Load
The feed, RPM and flute relationship used in milling.
Read Guide →NEWS & MACHINING NOTES
Latest Machining Articles
Practical articles covering CNC machining calculations, feeds and speeds, tooling, materials, setup and shop math.
MACHINING NOTE
Material Removal Rate: How CNC MRR Is Calculated
How width of cut, depth of cut and feed rate combine to describe material removal. This practical guide explains the calculation, the variables that matter and the checks to complete
Read Note
MACHINING NOTE
CNC Drilling Feed and Speed Basics
How drill diameter, cutting speed, feed per revolution and hole depth work together. This practical guide explains the calculation, the variables that matter and the checks to complete before using
Read Note
MACHINING NOTE
How to Reduce CNC Tool Deflection
How stickout, diameter, cutting load and setup rigidity affect deflection. This practical guide explains the calculation, the variables that matter and the checks to complete before using a value in
Read Note
MACHINING NOTE
CNC Surface Finish: Ra, Rz and What Affects the Result
How ra and rz describe surface texture and what machining variables influence finish. This practical guide explains the calculation, the variables that matter and the checks to complete before using
Read Note
MACHINING NOTE
How to Select a Tap Drill Size
How thread standard, pitch and target percentage of thread affect drill selection. This practical guide explains the calculation, the variables that matter and the checks to complete before using a
Read Note
MACHINING NOTE
How to Calculate CNC Cycle Time
How to estimate cutting time, account for non-cutting moves and separate setup from cycle time. This practical guide explains the calculation, the variables that matter and the checks to complete
Read NoteTHE TRUE MACHINISTS
Find the calculation. Check the reference. Get back to the job.
Use the calculator library as your first stop for everyday machining math.