Quilling Strip Length Calculator
Strip length for a rolled coil — the ring area over the paper thickness, which means the length goes as the diameter SQUARED.
This is a tight coil wound with no air in it. A loose coil allowed to spring open covers the same diameter with less paper, and how much less depends entirely on how loose — which no calculator can see. Treat the figure as the tight-coil case and the upper bound. Nothing is uploaded.
A coil is a ring seen end-on, so the strip goes as the diameter squared
The wound strip fills an annulus, and its cross-section is length times thickness. Divide the ring's area by the thickness and the length falls out with no spiral integral anywhere — π(D² − d²) / 4t. The D² is the whole story: doubling the diameter of a coil does not double the strip, it roughly quadruples it.
| Coil diameter | Strip needed | Turns | Standard 450 mm strips |
|---|---|---|---|
| 5 mm | 11.0 cm | 10 | 0.2 |
| 9.5 mm | 45.2 cm | 25 | 1.0 |
| 12 mm | 73.3 cm | 33 | 1.6 |
| 15 mm | 115.7 cm | 43 | 2.6 |
| 20 mm | 207.3 cm | 60 | 4.6 |
| 25 mm | 325.2 cm | 77 | 7.2 |
| 30 mm | 469.1 cm | 93 | 10.4 |
Which is why a standard 450 mm strip makes a coil of about 9.5 mm and not the centimetres people expect — and why the next size up always runs out. A 30 mm coil wants 10.4 strips joined together. The arithmetic is checked two ways here: dividing the ring by the thickness, and counting turns times the average circumference. They share no working and agree exactly.
And thinner paper needs more of it, not less
The thickness sits in the denominator, so halving it doubles the strip exactly. A 20 mm coil takes 207 cm of ordinary quilling paper and only 78 cm of card, because the card fills the same ring in far fewer turns.
| Paper | Thickness | Strip for a 20 mm coil | Turns |
|---|---|---|---|
| Very fine | 0.08 mm | 389 cm | 113 |
| Light quilling paper | 0.12 mm | 259 cm | 75 |
| Standard quilling paper | 0.15 mm | 207 cm | 60 |
| Heavy or textured | 0.25 mm | 124 cm | 36 |
| Card strip | 0.4 mm | 78 cm | 23 |
That is the opposite of the intuition that thicker paper, being more material, must eat more of the strip. It does use more material per millimetre — but it reaches the finished diameter so much sooner that the total comes out lower. A bigger core works the same way: starting on a fatter tool removes the tightest, shortest turns and cuts the length.
How to use
- Enter the coil diameter you want.
- Enter the core you are rolling on and the paper thickness.
- Read the strip length and the number of turns.
- Enter your strip length to see what it will actually make.
Frequently asked questions
How much strip does a quilled coil take?
Pi times the outer diameter squared less the core squared, all over four times the paper thickness. Seen end-on the wound strip fills a ring, and its cross-section is length times thickness — so the length is that area divided by the thickness.
Why does a 45 cm strip make such a small coil?
Because the length goes as the diameter SQUARED. A standard 45 cm strip on a 2 mm core in ordinary quilling paper rolls up to about 9.5 mm — under a centimetre, which surprises almost everyone the first time.
What happens if I want a coil twice as wide?
You need roughly four times the strip, not twice. Going from 10 mm to 20 mm takes the length from about 50 cm to about 207 cm, which is why the next size up always runs out mid-roll.
Does thicker paper need more strip?
No — less, which is the opposite of the intuition. The thickness is in the denominator: it uses more material per millimetre but reaches the finished diameter in far fewer turns, so the total comes out lower.
How many turns will the coil have?
The difference between the outer and core radii, divided by the paper thickness. A 20 mm coil on a 2 mm core in 0.15 mm paper is about 60 turns, which is also a useful sanity check on the length.
Is there a spiral formula involved?
There does not need to be. Treating the coil as a filled ring gives the exact answer with no integral at all, and it agrees precisely with counting turns and multiplying by the average circumference — two derivations that share no working.
Does this handle loose coils?
No. This is a tight coil wound with no air in it. A loose coil allowed to spring open reaches the same diameter with less paper, and how much less depends on how loose — so treat the figure as the tight-coil case and an upper bound.
Does this send anything anywhere?
No. Every figure is computed in your browser, and nothing is uploaded or stored.
🔒 This tool runs entirely in your browser. Nothing you enter is uploaded, logged, or stored.