Pi Tape Precision Diameter Measuring Tapes

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Pi Tape® tapes are the industry-standard tool for reading diameter — outside or inside — directly from any cylindrical surface without calculation.


Jealco International is an authorized Pi Tape® distributor, supplying the full Pi Tape line in imperial and metric models, in spring steel and stainless steel, and stocking it for order through our online store.. This guide covers how they work, the materials and finishes available, the complete model-and-size chart, and answers to the questions we hear most — then links you straight to the catalog to order.

How Pi Tapes Work



A Pi Tape wraps around the circumference of a cylinder — pipe, shaft, roller, drum, or tank — and displays the diameter directly on the graduated scale. Because the tape's graduations already account for π (pi), there's no calculation required: the reading you see is the actual diameter. This makes Pi Tapes faster and more accurate than calipers, or than calculating diameter from a separate circumference measurement, especially on large-diameter workpieces where calipers can't reach.


Pi Tapes read to a resolution of 0.001 in. (0.01 mm) depending on model, which is why they're specified for precision diameter verification in aerospace, oil & gas, and pressure-vessel work where a wrapped circumference-to-diameter calculation isn't accurate enough.

Materials & Finishes


Pi Tapes are available in two blade materials to match your environment:


  • 1095 spring steel is the standard, general-purpose choice for shop and field measurement.
  • 716 stainless steel resists corrosion and is preferred for wet, washdown, marine, food, and chemical environments, or wherever the tape will see moisture over its service life.


Most models are also offered in an Easy-to-Read "blue" finish, which increases graduation contrast for faster, lower-error reading in dim conditions or on large workpieces.

Outside & Inside Diameter Tapes


Pi Tapes come in both outside-diameter (OD) and inside-diameter (ID) versions.


OD tapes wrap around the outside of a pipe, shaft, roller, or vessel and read the outside diameter directly.


ID tapes measure the inside diameter of bores, rings, pipe interiors, and cylinders where an outside wrap isn't possible.


Both types read diameter directly with no π calculation, and both are available across the full imperial and metric range, in spring steel or stainless steel.

Applications


Pi Tapes are used wherever precise diameter measurement is required on round workpieces:



  • Pipes and piping systems (confirming nominal pipe size and wall fit)
  • Shafts and rollers in manufacturing and conveyor systems
  • Tanks, drums, and pressure vessels
  • Machined parts and precision components requiring diameter verification
  • Maintenance and inspection where calipers or micrometers can't reach


Pi Tape Models & Diameter Ranges


Each Pi Tape model covers a defined diameter range — select by the range that includes your target size. Every model is available in outside- or inside-diameter, spring or stainless steel, and standard or Easy-to-Read finish.



Quick Jump: Click on the link to take you to the desired Section:

Outside Diameter - Imperial  

Outside Diameter - Metric  

Inside Diameter - Imperial   

Inside Diameter - Metric

Shop the full Pi Tape catalog

173 models in stock to order — OD and ID, imperial and metric, spring steel and stainless. Most are built to order; order online or contact us to confirm lead time.


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Outside Diameter - Imperial

OD Tapes — Imperial (inch) - Click on the model number below for more information or to purchase
Diameter range 1095 Spring Steel Stainless Blue Easy-to-Read
0.5 – 2 in. P000 P000SS —
0.75 – 7 in. P01 P01SS P01EZ
0.75 – 9 in. P02 P02SS P02EZ
2 – 12 in. P1 P1SS P1EZ
2 – 24 in. P1SP P1SPSS P1SPEZ
12 – 24 in. P2 P2SS P2EZ
12 – 36 in. P2SP P2SPSS P2SPEZ
24 – 36 in. P3 P3SS P3EZ
24 – 48 in. P3SP P3SPSS P3SPEZ
36 – 48 in. P4 P4SS P4EZ
48 – 60 in. P5 P5SS P5EZ
60 – 72 in. P6 P6SS P6EZ
72 – 84 in. P7 P7SS P7EZ
84 – 96 in. P8 P8SS P8EZ
96 – 108 in. P9 P9SS P9EZ
108 – 120 in. P10 P10SS P10EZ
120 – 132 in. P11 P11SS P11EZ
132 – 144 in. P12 P12SS P12EZ

Every cell links to that exact model on the Jealco store. A dash (—) means that finish isn’t offered in that size. Extended-range SP models are listed in size order (e.g. P1SP falls between P1 and P2).

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Outside Diameter - Metric

OD Tapes — Metric (mm) - Click on the model number below for more information or to purchase
Diameter range 1095 Spring Steel Stainless Blue Easy-to-Read
15 – 50 mm PM000 PM000SS —
28 – 200 mm PM0 PM0SS PM0EZ
28 – 300 mm PM02 PM02SS PM02EZ
50 – 300 mm PM03 PM03SS PM03EZ
50 – 600 mm PM1SP PM1SPSS PM1SPEZ
100 – 300 mm PM1 PM1SS PM1EZ
300 – 600 mm PM2 PM2SS PM2EZ
300 – 900 mm PM2SP PM2SPSS PM2SPEZ
600 – 900 mm PM3 PM3SS PM3EZ
600 – 1200 mm PM3SP PM3SPSS PM3SPEZ
900 – 1200 mm PM4 PM4SS PM4EZ
1200 – 1500 mm PM5 PM5SS PM5EZ
1500 – 1800 mm PM6 PM6SS PM6EZ
1800 – 2100 mm PM7 PM7SS PM7EZ
2100 – 2400 mm PM8 PM8SS PM8EZ
2400 – 2700 mm PM9 PM9SS PM9EZ
2700 – 3000 mm PM10 PM10SS PM10EZ
3000 – 3300 mm PM11 PM11SS PM11EZ
3300 – 3600 mm PM12 PM12SS PM12EZ

Every cell links to that exact model on the Jealco store. A dash (—) means that finish isn’t offered in that size. Intermediate options PM02 (28–300 mm) and PM03 (50–300 mm) appear between PM0 and PM1; SP extended-range models are listed in size order.

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Inside Diameter - Imperial

ID Tapes — Imperial (inch) - Click on the model number below for more information or to purchase
Diameter range 1095 Spring Steel Stainless Blue Easy-to-Read
0.75 – 7 in. P01ID P01SSID P01EZID
0.75 – 9 in. P02ID P02SSID P02EZID
2 – 12 in. P1ID P1SSID P1EZID
2 – 24 in. P1SPID P1SPSSID P1SPEZID
12 – 24 in. P2ID P2SSID P2EZID
12 – 36 in. P2SPID P2SPSSID P2SPEZID
24 – 36 in. P3ID P3SSID P3EZID
24 – 48 in. P3SPID P3SPSSID P3SPEZID
36 – 48 in. P4ID P4SSID P4EZID
48 – 60 in. P5ID P5SSID P5EZID

Inside-diameter (ID) tapes are made in the sizes shown; larger diameters are outside-diameter only. Every cell links to that exact model on the Jealco store.

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Inside Diameter - Metric

ID Tapes — Metric (mm) - Click on the model number below for more information or to purchase
Diameter range 1095 Spring Steel Stainless Blue Easy-to-Read
28 – 200 mm PM0ID PM0SSID PM0EZID
28 – 300 mm PM02ID PM02SSID PM02EZID
50 – 300 mm PM03ID PM03SSID PM03EZID
50 – 600 mm PM1SPID PM1SPSSID PM1SPEZID
100 – 300 mm PM1ID PM1SSID PM1EZID
300 – 600 mm PM2ID PM2SSID PM2EZID
300 – 900 mm PM2SPID PM2SPSSID PM2SPEZID
600 – 900 mm PM3ID PM3SSID PM3EZID
600 – 1200 mm PM3SPID PM3SPSSID PM3SPEZID
900 – 1200 mm PM4ID PM4SSID PM4EZID
1200 – 1500 mm PM5ID PM5SSID PM5EZID

Inside-diameter (ID) tapes are made in the sizes shown; larger diameters are outside-diameter only. Every cell links to that exact model on the Jealco store.

Pi Tape FAQ

Is Jealco an authorized Pi Tape distributor?

How is a Pi Tape different from a regular measuring tape?

How do I choose between an imperial and a metric Pi Tape?

What diameter range can a Pi Tape measure?

What's the difference between spring steel and stainless steel Pi Tapes?

Where do I buy Pi Tapes, and are they in stock?

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