Tape Measure Versus Folding Rule

The folding rule was the measuring instrument of choice among carpenters and other tradesmen until the tape measure came along. Now, the tape measure gets all the glory, but the venerable folding rule still has its fan base. Here's how these two instruments compare.

Tape Measure

The tape measure consists of a steel ribbon or tape with linear distance measurement markings. The tape is rigid enough to remain stiff when extended for measuring purposes yet flexible enough to retract into the housing when not in use. The tape housing is generally square in shape and made from metal or plastic.

Measuring tapes come in a variety of different lengths from about 6 feet to 50+ feet. For everyday use, tapes in the 12 to 25 foot range are most common. Tapes are available with metric markings, English markings, or both metric and English markings.

The first patent for a retractable steel tape measure was filed by Alvin Fellows in 1868 but it wasn't until the early 1900's that the device started to make serious inroads into the folding wooden ruler market. By the latter half of the 20th century, tape measures were ubiquitous around the home and in the construction industry.

Folding Rule

A folding rule consists of multiple pivoting sections that unfold and lock in place to form a rigid ruler for taking length measurements. A typical folding rule is 6 to 8 feet long when extended. When not in use, the sections are folded back together into a compact bundle that is typically about 6" long. A folding rule is also called a carpenter's folding rule, a mason's rule or a zig-zag rule. Rules are available with metric or English markings, sometimes with both.

The folding rule has been around since at least since the mid 1800's. It was the standard measuring device used by tradesmen until the invention of the retractable tape measure. Originally made from wood, folding rules are now made from aluminum, steel, fiberglass, and wood. The pivoting hinges are often made from brass. The best folding rules have a sliding brass extension that is useful for taking inside measurements.

Tape Measure Advantages

Compared to the folding ruler, the tape measure is much more compact and more efficient in use. It can also be used with just one hand. Add in its ability to measure inside and outside distances and it's no wonder the retracting steel tape measure has become an indispensible tool for home and business use.

Unlike a wooden folding rule, the accuracy of a tape measure is not affected by changes in humidity. However, it should be thoroughly dried after use in wet conditions to prevent rusting of the tape and the internal coil spring.

 It is much quicker to extend or retract a measuring tape than a folding rule. Most measuring tapes will retract automatically unless pressure is applied to a sliding lock. Other designs will remain extended by default unless the operator explicitly presses a release latch.

Folding Rule Advantages

Although the folding rule has largely been replaced by tape measures, it still has its advantages. It is easier to take and transfer inside measurements (doorways, cabinet openings, etc.) with a folding rule thanks to the built-in extender. And it's more convenient than using a yardstick. Old school carpenters were also known to use a folding rule to wipe the sweat from their brow.

Masons have long favored folding rules for spacing courses of bricks using rules made with equally marked graduations for each brick course. Because of its rigidity, the folding rule also allows masons to take accurate measurements above their heads without climbing a ladder.

Experienced users will generally open the rule to the greatest length that fits between the points being measured, and then slide out the brass extension for the remaining distance. The extended rule can then be carried to the board to be cut which can then be marked directly from the rule without the need to keep track of any numbers.


A basic tape measure in the 12 to 16 foot range costs approximately the same or less than an 8 foot folding rule (somewhere between $5 to to $10).