What Pitch Do I need for Coil Binding?

Pitch is the single most important specification to get right when ordering coil binding supplies — and the most common source of frustration for first-time coil binders who discover too late that their coil and their punch machine don't match. A coil that's the wrong pitch simply will not thread through the holes, no matter how much effort you apply. Understanding pitch takes about two minutes, and it prevents this mistake permanently. This guide covers what pitch means for coil binding, how to identify which pitch your machine uses, and how to make sure every coil order matches your equipment.

For a broader overview of the coil binding system before reading about pitch specifically, see our introductory guide on what coil binding supplies you should have.

What Is Coil Binding Pitch?

In coil binding, pitch refers to the number of holes punched per inch along the binding edge of the document. The two standard coil binding pitches are 4:1 (four holes per inch) and 5:1 (five holes per inch). A 4:1 pitch punch creates holes spaced 1/4 inch apart — four holes in every linear inch of the binding edge. A 5:1 pitch punch creates holes spaced 1/5 inch (0.2 inches) apart — five holes in every linear inch. These two hole patterns are close enough in appearance that they're easy to confuse visually, but they're different enough in actual spacing that a 4:1 coil won't thread through a 5:1 punched document, and vice versa.

The pitch of the coil itself corresponds to these hole spacings — a 4:1 coil has turns spaced 1/4 inch apart that align with 4:1 punched holes, and a 5:1 coil has turns spaced 1/5 inch apart that align with 5:1 punched holes. Matching coil pitch to punch pitch is the fundamental coil binding compatibility requirement. For the broader context of what pitch means across all binding systems, see our dedicated pitch overview at what does pitch mean.

4:1 vs 5:1 — Which Is More Common?

4:1 pitch — the office standard

4:1 pitch is the more common of the two coil binding pitches for standard office and professional document applications. Most desktop coil binding machines sold for office use are 4:1 pitch, and the majority of standard spiral coil product listings default to 4:1. If you're purchasing a coil binding machine for the first time and haven't specified otherwise, it's almost certainly 4:1 pitch.

4:1 pitch produces slightly larger holes and uses coil with slightly larger-diameter helix turns, which makes it a bit more forgiving during manual threading — the larger gap between turns is a little easier to align when threading the coil through pages. For guidance on threading technique for both pitches, see our step-by-step article on how to bind using spiral coil.

5:1 pitch — for larger coil diameters

5:1 pitch is primarily used for larger coil diameters — coils above 30mm (approximately 1.25 inches in diameter) are typically only available in 5:1 pitch, because the 4:1 spacing becomes mechanically problematic at large coil diameters. If you regularly bind thick documents requiring large-diameter coils, your machine may need to be 5:1 pitch to access the full diameter range. For guidance on large-diameter coil binding for thick documents, see our article on how to bind a large document.

How to Identify Your Machine's Pitch

Check the machine documentation

The machine's user manual, product page, or specification label will state the pitch as "4:1" or "5:1." This is the most reliable identification method. If the manual isn't available, the model number can typically be searched online to find the specification.

Measure the hole spacing on a test punch

Punch a single sheet through the machine and measure the distance between hole centers with a ruler. Holes spaced 1/4 inch (6.35mm) apart center-to-center → 4:1 pitch. Holes spaced 1/5 inch (5.08mm) apart → 5:1 pitch. The difference of about 1.3mm is small but measurable with a standard ruler on a sample of 4 to 5 consecutive holes.

Count holes on a letter-size sheet

A 4:1 pitch punch produces approximately 43 to 44 holes on a letter-size sheet (11 inches × 4 holes per inch). A 5:1 pitch punch produces approximately 54 to 55 holes. If you have a punched sheet and need to identify its pitch, counting holes is a reliable method.

How to Order the Right Coil for Your Machine — Step-by-Step

Step 1 — Confirm your machine's pitch

Use any of the identification methods above. Write it down before ordering.

Step 2 — Measure your typical document thickness

Stack a representative document (all pages plus covers) and measure the thickness at the binding edge. This measurement determines the coil diameter you need — match the coil's rated capacity to your document thickness.

Step 3 — Select coil with matching pitch and appropriate diameter

Filter coil products by your pitch (4:1 or 5:1) first, then by diameter. Coil diameter should match or slightly exceed your document thickness. For guidance on coil diameter selection alongside pitch, see our coil supplies guide at what coil binding supplies you should have.

Step 4 — Confirm coil length matches your document binding edge

Standard coil lengths are 12 inches for letter-size documents and 14 inches for legal-size. Confirm the coil length covers the full binding edge of your document with a small overlap for crimping.

Step 5 — Order a test quantity before bulk purchase

For any new coil specification, order a small test quantity and bind one document before committing to a large order. Verify the coil threads cleanly and the finished document opens and closes properly. For coil crimping guidance that finishes the binding correctly, see our crimper guide at how to use coil crimpers.

Quick Reference — Coil Binding Pitch Comparison

Troubleshooting

Coil won't thread through the punched holes at all

The coil pitch doesn't match the punch pitch. The turns of the coil are spaced either too close or too wide to align with the hole pattern. Measure hole spacing to confirm pitch, then order the correct matching coil.

Coil threads partway then gets stuck

The coil diameter is too large for the punched hole size, or the punched holes are irregular (partial holes at the document edge). Confirm the coil diameter is appropriate for the document thickness and that you're not punching too many sheets at once.

Can't tell 4:1 from 5:1 holes visually

They look very similar by eye. Use a ruler to measure center-to-center distance between holes: 6.35mm = 4:1; 5.08mm = 5:1. Alternatively, count the holes across an 11-inch letter sheet: 43–44 = 4:1; 54–55 = 5:1.

Machine box says 'spiral' but doesn't specify pitch

Some older product descriptions used 'spiral' without specifying pitch. Search the full model number for a specification sheet. If unavailable, measure a test-punched sheet as described above.

Ordered the wrong pitch — have a large quantity of mismatched coil

Coil cannot be made to work across pitch mismatches — the turn spacing is physically different. Return unused coil to the supplier. In the future, always confirm pitch before bulk orders.

Frequently Asked Questions

Is 4:1 or 5:1 pitch better?
Neither is inherently better — the right pitch depends on your machine and your typical document thickness. 4:1 is the standard for most desktop office coil binding. 5:1 is needed for large-diameter coils. Match to your machine's punch, not to a preference. See our pitch overview at what does pitch mean.

Can I use a 4:1 punch with 5:1 coil?
No. The hole spacing of 4:1 punched holes is 6.35mm and the turn spacing of 5:1 coil is 5.08mm — they are not compatible. Threading a mismatched coil is physically impossible.

How many holes does a standard coil binding machine punch on a letter sheet?
A 4:1 machine punches approximately 43 to 44 holes. A 5:1 machine punches approximately 54 to 55 holes. The exact count depends on how far the punched area extends from the document edges.

What pitch do most binding supply stores default to?
Most binding supply stores default to 4:1 pitch because it's the more common office standard. When ordering without specifying pitch, you'll likely receive 4:1 supplies. Always confirm pitch when ordering. For the full range of coil binding supplies, see what coil binding supplies you should have.

Does wire binding use the same pitch system?
Wire binding (twin-loop wire-O) uses its own pitch system, separate from coil binding. The most common wire binding pitches are 2:1 and 3:1, and the compatibility requirement is the same — punch pitch must match wire pitch. See our dedicated wire binding pitch guide at what pitch you need for wire binding.