Machining Calculators

Every calculator and chart on the site, grouped by the job at the machine. Each one shows the formula and the steps with your numbers, keeps its inputs in the link so you can share or repeat a result, and prints a dated record. Nothing you type is uploaded.

Speeds, feeds and cutting

• Speeds and feeds calculator — spindle RPM and feed rate for milling, drilling and turning.
• SFM calculator — surface feet per minute or m/min to RPM, and back.
• Chip load calculator — feed per tooth from the feed rate, with radial chip thinning.
• Material removal rate calculator — MRR for milling, turning and drilling, and spindle power.
• Surface finish calculator — Ra, RMS and N grades, turned finish from feed and nose radius, cusp height.
• G code list — search G-codes and M-codes with what they do and an example block.

Drills, taps and threads

• Drill and tap chart — tap drill size and % of thread for UNC, UNF and metric threads.
• Drill size chart — number, letter, fractional and metric drills in inches and mm.
• NPT tap drill chart — tap drills and gauge dimensions for pipe threads.
• Thread pitch calculator — pitch and minor diameters, thread depth, 3-wire measurement.
• Decimal to fraction inches — nearest fraction of an inch, with a 64ths chart.
• Machine screw size chart — #0 to 1/2 in screw diameters, UNC and UNF threads per inch and tap drills.
• Drill point calculator — drill point length and the depth of the tip for blind and through holes.
• Tenths to inches calculator — tenths, thou, mil, microinches and mm to decimal inches.
• Thermal expansion calculator — length change of a metal part with temperature.
• Thread milling calculator — RPM, corrected programmed feed, helical turns and time for internal or external threads.

Hole patterns, angles and edges

• Bolt circle calculator — X/Y coordinates of every hole on a bolt circle.
• Sine bar calculator — gauge block height and stack for an angle.
• Taper angle calculator — included angle, compound setting and taper per foot.
• Chamfer calculator — chamfer sizes and chamfer mill depth.
• Countersink depth calculator — depth for a countersink diameter at any angle.

Inspection

• True position calculator — GD&T position from measured coordinates, with MMC bonus.
• GD&T symbols chart — the 14 geometric tolerance symbols, what each controls, datum use and tolerance zone.