Pipe offset examples, worked

Eight offsets worked out by hand with the formulas, each followed by what the calculator prints. Results are rounded to the nearest 1/16 inch; the decimal is the value to four places.

1. 10″ offset at 45°

  • Travel = 10 ÷ sin 45° = 14.1421″ (sin 45° ≈ 0.7071), which is 14-1/8″ (1′ 2-1/8″).
  • Run = 10 ÷ tan 45° = 10.0000″ (tan 45° ≈ 1.0000), which is 10″.

2. 12″ offset at 30°

  • Travel = 12 ÷ sin 30° = 24.0000″ (sin 30° ≈ 0.5000), which is 24″ (2′ 0″).
  • Run = 12 ÷ tan 30° = 20.7846″ (tan 30° ≈ 0.5774), which is 20-13/16″ (1′ 8-13/16″).

3. 6″ offset at 22.5°

  • Travel = 6 ÷ sin 22.5° = 15.6788″ (sin 22.5° ≈ 0.3827), which is 15-11/16″ (1′ 3-11/16″).
  • Run = 6 ÷ tan 22.5° = 14.4853″ (tan 22.5° ≈ 0.4142), which is 14-1/2″ (1′ 2-1/2″).

4. 24″ offset at 60°

  • Travel = 24 ÷ sin 60° = 27.7128″ (sin 60° ≈ 0.8660), which is 27-11/16″ (2′ 3-11/16″).
  • Run = 24 ÷ tan 60° = 13.8564″ (tan 60° ≈ 1.7321), which is 13-7/8″ (1′ 1-7/8″).

5. 8-1/2″ offset at 11.25°

  • Travel = 8.5 ÷ sin 11.25° = 43.5696″ (sin 11.25° ≈ 0.1951), which is 43-9/16″ (3′ 7-9/16″).
  • Run = 8.5 ÷ tan 11.25° = 42.7324″ (tan 11.25° ≈ 0.1989), which is 42-3/4″ (3′ 6-3/4″).

6. 36″ offset at 45°

  • Travel = 36 ÷ sin 45° = 50.9117″ (sin 45° ≈ 0.7071), which is 50-15/16″ (4′ 2-15/16″).
  • Run = 36 ÷ tan 45° = 36.0000″ (tan 45° ≈ 1.0000), which is 36″ (3′ 0″).

7. 10″ offset at 90°

  • Travel = 10 ÷ sin 90° = 10.0000″ (sin 90° ≈ 1.0000), which is 10″.
  • Run = 0, because at 90° the line turns straight over, which is 0″.

8. Rolling offset: set 15, roll 8, at 45°

  • True offset = √(15² + 8²) = √289 = 17.0000″, which is 17″ (1′ 5″).
  • Travel = 17.0000 ÷ sin 45° = 24.0416″, which is 24-1/16″ (2′ 1/16″).
  • Run = 17.0000 ÷ tan 45° = 17.0000″, which is 17″ (1′ 5″).

Check your own

Put the same numbers in the calculator and compare. For a shortcut through the trig, see the multiplier chart.

How this was checked

The numbers on this page come from the same formulas as the Pipe Offset Calculator iPhone app, and an automated test compares them with the app’s own code on a grid of inputs (last run ). This is trigonometry, not a code or standards reference, and it does not subtract fitting take-outs. If something here is wrong, tell us at a@noshu.net.