Taper Calculator

What Is a Taper Calculator?

A taper calculator is a free online tool for machinists and engineers that computes taper dimensions for machining operations. It calculates taper per inch (TPI), taper per foot (TPF), taper angle, or length based on the major and minor diameters of a tapered workpiece. This tool is essential for lathe work, milling, and inspection of tapered parts.

How to Use the Taper Calculator

Select your calculation mode and enter the known values:

1. Choose calculation mode – Select what you want to calculate: Taper (TPI/TPF/angle), Length, or Angle.
2. Select unit – Choose from mm, cm, m, inches, or feet for the diameter and length inputs.
3. Enter major and minor diameters – The larger and smaller end diameters of the taper.
4. Enter known value – Depending on mode: taper length or taper angle.

The calculator instantly shows TPI, TPF, taper angle, and length based on your inputs.

Taper Formulas

Taper calculations use the following formulas:

• Taper per inch (TPI): $\text{TPI} = \frac{D_l - D_s}{T_l}$
• Taper per foot (TPF): $\text{TPF} = 12 \times \text{TPI}$
• Taper angle: $\theta = \arctan(\text{TPI} / 2)$
• Length from angle: $T_l = \frac{D_l - D_s}{\text{TPI}}$ where $\text{TPI} = 2 \times \tan(\theta)$

Where $D_l$ is the major (larger) diameter and $D_s$ is the minor (smaller) diameter.

For related machining calculations, try the Pitch Diameter Calculator for threads and the Angle Converter for angle unit conversions.

Applications of Taper Calculations

Taper calculations are used in lathe setup for turning tapered shafts and pins, milling machine setup for dovetails and angled surfaces, inspection and quality control of machined parts, tool and die making, and automotive and aerospace component manufacturing. Understanding taper is crucial for ensuring proper fit and alignment of mating parts.