Torque Toolbox is a bolt torque calculator and workshop reference for mechanics, fitters, machinists and DIYers. Get the right tightening torque in seconds, plus tap drill sizes, drill charts and feeds & speeds. Everything works offline, so it's ready in the shed, on site or under the car.

Stop tabbing between browser windows at the bench. Torque Toolbox puts the numbers you need in one fast app.

BOLT TORQUE CALCULATOR
• Step-by-step torque setup: thread size, pitch, bolt grade, materials, lubrication, application and gasket
• Metric, UNC and UNF threads, coarse and fine pitch
• Results in Nm and lb-ft with a ±10% range
• Show Calculation: see the formula and the numbers behind every result
• Advanced options for custom preload and K factor

TORQUE CHARTS & TIGHTENING SEQUENCES
• Bolt grade chart, including head markings
• Star pattern and staged tightening sequences for flanges, wheels and covers

TAP DRILL & DRILL SIZE CHARTS
• Drill & Tap calculator: the right tap drill size for Metric, UNC and UNF threads, then torque that bolt in one tap
• Tap drill chart for quick lookups
• Drill bit size converter: metric, fractional, decimal, number and letter drills side by side, plus the nearest standard sizes

FEEDS & SPEEDS FOR LATHE AND MILLING
• Spindle RPM, feed rate and cutting speed for turning, facing, parting and milling
• Settings for mild steel, stainless steel, aluminium, brass, cast iron and tool steel, with HSS or carbide tools

UNIT CONVERTER
• Torque: Nm to ft-lb, lb-in, kgf-m and more
• Length, weight, temperature, speed, pressure, power, area, volume and other workshop units
• Decimal to fraction conversions

SAVED CALCULATIONS
• Save torque, drill & tap and machining setups, and reuse them for repeat jobs

Built by a mechanical fitter, for people who work with their hands. Clear and simple, with the working shown, not just a number.

Built for: Machinists · Mechanical Fitters · Mechanics · Fabricators · Maintenance Trades · Apprentices · Workshop Technicians · Serious DIY & Automotive Users

Torque values are estimates only. Always verify against manufacturer specifications and approved procedures for critical applications.