CoilCalc: Roll Length MeterCoilCalc: Roll Length Meter
Measure remaining length on any roll — without unrolling
Download on the App Store
Screenshots
Features
Quick Registration with Presets
Add a new roll in seconds with pre-configured presets for tape, wire, rope, paper, ribbon, and film. Customise thickness and core size for any material.
Precise Remaining Length Calculation
Using roll geometry formulas, CoilCalc calculates the exact remaining length from outer diameter, inner diameter, and material thickness. Accurate to the metre.
Camera Measurement
On iOS 17+, use your iPhone camera to measure roll diameters automatically. No manual measuring needed — just point and capture.
Use Counter
Track how many times each roll has been used. Know when it's time to order a replacement before you run out mid-project.
Home Screen Widget
Add a widget to your home screen to check remaining lengths of your most-used rolls at a glance. No need to open the app.
Fully Offline & Private
All calculations and data stay on your device. No account, no internet connection, no data collection, no tracking of any kind.
One-Time Purchase
Pay once and own CoilCalc forever. No subscriptions, no ads, no hidden fees. All features included.
Multiple Material Support
Works with any roll material: tape, paper, wire, cable, rope, ribbon, film, fabric, string, twine, and more.
Never unroll a spool again just to check how much is left. CoilCalc instantly tells you the remaining length of any roll material — tape, paper, wire, rope, ribbon, cable, or film — using just two diameter measurements.
Simply enter the outer diameter, inner diameter (core size), and material thickness. CoilCalc uses precise roll geometry calculation to give you an accurate remaining length in seconds. No more guessing, no more wasted material, no more unrolling across the workshop floor.
Camera Measurement for iOS 17+ — use your iPhone camera to measure diameters automatically
Calculation Presets — pre-configured for tape, wire, rope, paper, ribbon, and film
Use Counter — track how many times each roll has been used
Home Screen Widget — check your most-used rolls at a glance
Fully Offline — your data stays on your device, no account or internet required
One-Time Purchase — no subscriptions, no ads, no tracking of any kind
Whether you work in construction, electrical, packaging, crafts, or manufacturing, CoilCalc turns your iPhone into an essential workshop tool.