Estimate how many parts fit on a 7 inch or 13 inch reel, or how many reels a job needs, using published EIA-481 reel dimensions.
Choose your reel and tape, and the estimate updates as you type.
Nominal reel inner width (W1) and maximum overall widths (W2, W3) in millimetres, from the published reel drawing in manufacturer specification TB347.
| Tape width | W1 (nominal) | W2 (maximum) | W3 (maximum) |
|---|---|---|---|
| 8 mm | 8.4 | 14.4 | 10.9 |
| 12 mm | 12.4 | 18.4 | 15.4 |
| 16 mm | 16.4 | 22.4 | 19.4 |
| 24 mm | 24.4 | 30.4 | 27.4 |
| 32 mm | 32.4 | 38.4 | 35.4 |
| 44 mm | 44.4 | 50.4 | 47.4 |
How it is calculated. Tape length = pi x (outer radius squared minus hub radius squared) / tape thickness, with the outer radius taken as 3 mm inside the flange edge. Parts per reel = (tape length minus leader and trailer) / pitch. Sources: Renesas TB347 tape and reel specification (reel sizes, hub sizes, W1 to W3, pitch rules); ST technical note TN1205 (leader and trailer minimums); CompuPhase reel estimate method (winding geometry).
It uses the geometry of a tape wound on a reel, with reel and hub sizes taken from published manufacturer specifications that follow EIA-481. Every input can be changed to match your own tape and reel drawing.
The maximum number of pockets a reel can hold for your tape thickness and pitch, after leader and trailer.
Enter a quantity to see how many reels it needs and how many parts go on the last reel.
Shows the nominal reel inner width (W1) for your tape width, so you can check the tape fits the reel.
Four inputs give a useful estimate. The rest have sensible defaults from the published specifications.
Pick the reel size and hub from your reel drawing or supplier.
Choose the tape width and the cavity pitch (P1) from the component datasheet or tape drawing.
Enter the overall thickness of the loaded tape. Measure it with calipers if you can.
Add a quantity if you want to know how many reels the job needs.
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Short answers to what buyers usually ask first.
Work out the length of tape the reel can hold from its outer diameter, hub diameter and tape thickness, then divide by the cavity pitch. Take off the leader and trailer, which are empty. This calculator does the sums for you.
The calculator gives a maximum for a tightly wound reel. Manufacturers usually pack a standard quantity below that maximum, and a loosely wound reel holds less. The leader and trailer also take up tape.
Cavity pitch (P1) follows the component size. For most tapes it is a multiple of the 4 mm sprocket hole pitch, and for 32 mm and 44 mm tape it starts at 8 mm. Very small parts can use smaller pitches. Check the component datasheet or tape drawing.
Published manufacturer specifications that follow EIA-481 supply tape on 7 inch (178 mm) and 13 inch (330 mm) reels, with different hub sizes. Check the reel drawing for your job.
Yes. We tape and reel loose, tubed and trayed components. See our SMD taping and reeling service, or send us the device, quantity and deadline.
Tell us what you need on reels. Add a phone number if you would like a call back, or call us on 01604 491107.
Converting, programming, testing, and packaging electronic components for defence, aerospace, automotive, and medical manufacturers since 1992.
Tel: (01604) 491107
info@systemationeuro.com
Systemation Euro Automotive Ltd
19 Mansion Close
Moulton Park Industrial Estate
Northampton
NN3 6RU
England
