SpanCheck

Measure fast with AR. Know how much you can trust the number — and how to tighten it.

Most phone AR rulers give you a big number and no sign of how wrong it might be. SpanCheck shows the estimated error range next to every measurement, then tells you exactly what to change to shrink it.

"HOW TO TIGHTEN IT"
Every result, AR or photo, is broken down by error cause, with the ± you would get if you changed one thing:
• "Re-pin from 50 cm: ±14.2 mm"
• "The card is only 30% of the photo width — shoot closer"
• "AR can't go below ±10 mm → measure with an A4 sheet in Precision"
Each suggestion comes with a one-tap action: re-pin, retake the photo, or open Precision Mode. The projected ± comes from the same error model as the result itself.

TOLERANCE BAND
Results are drawn as a point on a ± band, not as a bare number. The band widens when a measurement is less certain, so accuracy is something you see rather than guess.

AIM, PIN, READ
Point the ring at one end and pin it, then the other end. Live distance and ± update while you aim. A light tick confirms each pin, and short coaching tips tell you when to move slowly or add light. AR results are typically in the ±1–5 cm class, depending on distance and tracking, and are never reported below ±10 mm.

PRECISION MODE
When millimetres matter, put a reference object you already own (a credit card, A4 or Letter paper) on the same surface and take a photo. SpanCheck removes the perspective and draws a grid of the reference surface so you can check it lines up. A loupe magnifies the photo while you set each corner. Accuracy depends on the reference and the span: with a credit card in the same photo, a 30 cm span comes to about ±2 mm. Longer spans widen the range, and an A4 or Letter sheet works better for them. The range is never shown below ±1.0 mm. No card at hand? Tap "Try with a sample photo" to try the mode on a built-in photo of a card next to a tile. Your photos never leave your device.

A LOG SORTED BY CERTAINTY
Every saved measurement keeps its method and error range. Sort by most certain first. With SpanCheck Pro, share any measurement as a drawing with a title block (item, value, tolerance, method, date) and export everything to CSV.

WORKS WITHOUT AR
No ARCore on your device? Precision Mode and manual entry still work, so the app is useful on every phone or tablet.

Millimetres or inches, switched with one tap right where you read the number.

SPANCHECK PRO
Free: AR and Precision measuring, "How to tighten it" for every result, and up to 10 saved measurements (with ads).
Pro: unlimited saved measurements, shareable measurement drawings, CSV export, a browser dashboard on your Wi-Fi, and no ads. 7-day free trial, then $3.99/month or $19.99/year, or $49.99 once for lifetime access (prices vary by region). New installs also include 7 days of Pro features at no cost (ads stay on).

Terms of Use: https://app.mint-soft.com/apps/spancheck/terms
Privacy Policy: https://app.mint-soft.com/apps/spancheck/privacy

Recent changes:
First release of SpanCheck.
• Every length comes with its ± error range.
• How to tighten it: each result is split by error cause, with the ± after one change and a one-tap fix.
• AR: live distance and ± while you aim.
• Precision Mode: photo with a card, A4 or Letter sheet — about ±2 mm on a 30 cm span with a card. Sample photo included.
• History sorted most certain first.
• Share measurement drawings (Pro).