Screw Thread Turns Calculator
How many turns of a screw or thread to move a set distance, or how far a number of turns moves it: metric, UNC, UNF or any pitch, in turns and degrees.
New: please check your results.
For guidance only. This is not a substitute for a qualified engineer, and important designs should be checked by one.
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- Turns needed
- 2 turns
- In whole turns and degrees
- 2 turns
- Movement per full turn
- 1 mm
- Movement per quarter turn
- 0.25 mm
- Turn for each 0.1 mm
- 36°
What it does
Each full turn of a screw moves it along by one pitch, the distance from one thread to the next: an M6 screw (1 mm pitch) moves 1 mm per turn, so raising something 2 mm takes 2 turns. This works out how many turns (and degrees) you need to move a set distance, or how far a number of turns will move it, for metric, UNC and UNF threads or any pitch you enter.
How to use it
- Work out
Turns: how far to turn the screw to raise, lower or move something by a set amount. Distance: how far it moves when you turn it a set amount.
- Thread type
Most screws, bolts and levelling feet are metric coarse (an M6 moves 1 mm per turn). UNC and UNF are American inch threads. For anything else, such as a lead screw or an adjuster, enter its pitch or threads per inch.
- Thread size
The metric coarse size, as written on the screw, bolt or drawing.
- Thread size
The metric fine size, as written on the screw, bolt or drawing.
- Thread size
The UNC size, as written on the screw, bolt or drawing.
- Thread size
The UNF size, as written on the screw, bolt or drawing.
- Pitch
The distance from one thread to the next, measured along the screw. Measure across 10 threads and divide by 10 for accuracy, or use a thread gauge.
- Threads per inch
Count the threads along one inch of the screw (or along half an inch and double it).
- Thread starts
Nearly every screw and bolt has one start. Some lead screws, jar lids and quick adjusters have 2 or more threads wound side by side (look at the end: count the separate thread ends). The screw then moves pitch × starts per turn.
- Distance to move
How far you want the screw, foot or part to move, e.g. raise a washing machine foot by 3 mm.
- Number of turns
Full turns of the screw; use decimals for part turns (0.25 is a quarter turn, 0.5 a half turn).
Common uses
- Levelling washing machines, fridges and kitchen units on their adjustable feet.
- Levelling a lathe, mill or machine bed with jacking or levelling screws.
- Levelling a 3D printer bed: an M3 screw moves 0.5 mm per turn.
- Adjusting hinges, guitar truss rods and saddles, and telescope and camera mounts.
- Checking how far a lead screw or vice moves per turn of the handle.
- Looking up a thread's pitch. Try the Tap Drill Size Calculator
- Tightening the bolts to the right torque. Try the Bolt Torque Calculator
The formula
Lead = pitch × number of startsTurns = distance ÷ leadDistance = turns × leadPitch (UNC, UNF or TPI) = 1 inch ÷ threads per inchWhere:
- pitch
- the distance between neighbouring threads, along the screw (1 mm for M6, 1.25 mm for M8)
- lead
- how far the screw moves in one full turn; the same as the pitch for an ordinary single-start screw
- 1 turn
- 360°, so a quarter turn is 90° and moves a quarter of the lead
The screw moves exactly one lead per turn whatever its diameter. Any slack in the thread (backlash) is taken up first when you change direction, so come up to the final position in the same direction each time.
Worked example
Moving an M6 (1 mm pitch) screw by 2 mm:
- Lead (movement per turn): 1 mm pitch × 1 start = 1 mm
- Turns: 2 mm ÷ 1 mm = 2 turns
- Each quarter turn moves it 0.25 mm
Questions people ask
How far does an M6 screw move in one turn?
1 mm, its pitch. An M3 moves 0.5 mm, M4 0.7 mm, M5 0.8 mm, M8 1.25 mm, M10 1.5 mm and M12 1.75 mm per turn (metric coarse threads). Fine threads move less per turn, which is why they're used for precise adjusters.
How do I find the pitch of a screw?
Check the size on the packaging or drawing (M8 is 1.25 mm unless it says otherwise, such as M8 × 1). Otherwise measure across 10 threads with a ruler or calipers and divide by 10, or use a thread gauge. For inch screws, count the threads in one inch to get the TPI.
Which way do I turn it?
Almost all screws have a right-hand thread: turning clockwise (seen from the head) screws it in, and anticlockwise unscrews it. On a levelling foot that usually means clockwise raises the foot into the appliance (lowering it) and anticlockwise extends it.
Last checked 30 October 2026 · Last rev. 31 October 2026 · 30ec