How-to guide

How to count joists and studs at centres

Name: How to count joists and studs at centres
Uploaded: 2026-10-31
Duration: 34 s
Description: How to count floor joists at 400 mm centres and studs at 600 mm centres from a PDF drawing, with their total length. Free software, step by step.

How many joists at 400 centres across this room? How many studs at 600 along that wall? Takeoff Studio's Spacing tool works it out from the drawing: set the centres, draw the run or the area, and it places and counts every member, with their total length. It's free on Windows, and your drawing never leaves your PC.

4 stepsFreeVideo 34 seconds

Step by step

Open the drawing and set the scale

Open the drawing with Load PDF, then set the scale: Set Scale from Title Block in the PDF tab, or Calibrate (R) from a dimension you trust. Spacing needs a calibrated page, because the centres are real distances.

Lay joists across an area

Choose Spacing on the toolbar (J). In the bar above the drawing set Lay to Across an area, type the Centres (400mm, 0.4 m and 16" all work) and pick the direction the joists run - Horizontal, Vertical or an angle. Click round the room and press Enter. Each joist is drawn and clipped to the outline: here 16 joists, 57.97 m in all.

Place studs along a line

For studs, posts or fixings, set Lay to Along a line, type the centres (600mm) and choose the Ends - both ends, start only or neither. Click along the wall and press Enter. A tick marks each item and the count shows on the drawing: 11 studs along this partition.

Check the count and carry on

Select a spacing markup to see its count, centres and member length in the Selection tab, and change the centres, ends or direction there - or drag its points - and the count updates straight away. Spacing runs go into the Totals (a count and a length) and the schedule.

Tips

Give each run a name such as Floor joists 47x200 C24 so the totals group by size.
Ends matter: both ends gives one more than the number of spaces. Use Neither end for intermediates between existing posts.
For noggins or extra studs at openings, add them as a separate Count (C) - the Spacing tool only places members at regular centres.
Same layout on several floors? Set Times in the Selection tab rather than drawing it again.
With Takeoff Studio Pro, the Stud partition assembly turns one wall into studs, plasterboard sheets, screws and labour with formulas, using variables such as Height and Spacing.

Frequently asked questions

Is the Spacing tool free?

Yes. The Spacing tool and every other measuring tool are free in Takeoff Studio, with no account. Takeoff Studio Pro (£24.99 a month or £199.99 a year, first month free) adds assemblies, exports, costed schedules and more.

Does it give the total length of the joists?

Yes. Across an area, each member is clipped to the outline, and the total member length is shown with the count - in the label, the Selection tab, the schedule and the Totals.

Can I use imperial centres?

Yes. Type 16" or 2' for the centres, and switch the display to feet and inches in View Options if you want the lengths in imperial too.

Are my drawings uploaded anywhere?

No. Takeoff Studio is a Windows app and works offline - the PDF and your measurements stay on your PC.