Span64
A construction calculator built around the way measurements are written
Feet, inches and fractions belong together. Span64 lets you calculate with them directly, convert to metric and keep the working in a saved Tape, on iPhone, iPad and Android.
We created Span64 as our own product in 2026: concept, design and development, from the calculation engine to the native apps.
- Our role
- Concept, design, iOS, Android
- Engagement period
- 2026
- Platforms
- iPhone, iPad, Android
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Span64
A measurement on a job site is rarely just a decimal. We built Span64 to handle dimensions as they are taken: feet, inches, fractions and metric units, with the equation kept visible and the result ready to use.
From a measurement to the next cut
- Exact dimension arithmetic, with feet, inches and stacked fractions
- Imperial and metric conversion, without retyping the calculation
- Tape: saved calculations with notes that give the numbers context
- Seven construction tools, including Stairs, Roof / Rafter and Studs / On-center
- Local calculations and working data, without an account or a data backend
Concept & decisions
The central decision was to preserve dimensions as exact values in a shared Kotlin Multiplatform engine. SwiftUI on iOS and Compose on Android each provide a native interface around that same calculation core.
A construction tool needs more than a final number. Stairs places the inputs, drawing, results and checks in one flow. The checks flag the limits used for that calculation; they do not certify compliance with local building rules.
Look & Feel
We designed the interface around a readable equation, a large result and fractions stacked as fractions. Unit keys and quick fraction buttons keep the measurement close to the way it is written.
Drawings connect the geometry to its inputs and results. Tape keeps calculations and notes together so the next visit starts with the working, rather than an unexplained number.
Calculations and saved working data are available offline. Buying or restoring the tool unlock requires a connection; local work does not depend on a purchase connection.
Contact us
Shall we talk about your project? Email us at hello@irakai.com
We reply within two business days.