# KnownGood — Instrument Calibration Log

> Instrument Calibration Log (iPhone/iPad app by D4N LTD.)

- Source: https://appshunter.io/ios/app/knowngood/id6824103602 (this page in markdown: same URL + `.md`)
- Developer: [D4N LTD](https://appshunter.io/developer/1212131887)
- Category: Business, Productivity
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 17.0 · 3 MB
- Languages: American English
- Released: 2026-11-02
- Data updated: 2026-11-07

## What is KnownGood?

KnownGood keeps a dated record of your test instruments: calibration certificates, due dates, your own checks between certificates, and a signed PDF record you can hand over.

Built for UK electricians, gas engineers, and fire alarm and emergency lighting engineers who look after their own test instruments.

INSTRUMENT REGISTER
- Multifunction testers, insulation and loop testers, flue gas analysers, detector testers, lux meters and more
- Make, model, serial number, asset ID and status for each instrument
- In use, away for calibration or repair, or retired

CALIBRATION CERTIFICATES AND DUE DATES
- Record the calibration date, lab, certificate number, due-by date and as-found result
- Attach a photo or PDF of the certificate
- Each instrument shows its certificate due date
- If you allow notifications, KnownGood reminds you 30 days and 7 days before the due date, and on the day

YOUR OWN CHECKS
- Set up each instrument's functions and test points once
- Record the reference you used and each reading
- The first check after a certificate sets your baseline
- Readings outside the baseline and tolerance you chose are marked Flagged, so you can decide what to do

TIMELINE
- Log repairs, damage, loans and other events
- See certificates, checks and events for each instrument, newest first

PDF INSTRUMENT RECORD
- One record per instrument: certificates, checks with the reference used, events, remarks and your sign-off
- A4 pages. Share, print or save to Files

FREE
- One active instrument with certificates, checks, events, reminders and PDF export
- No ads, no time limit

KNOWNGOOD PRO
- Unlimited instruments
- Your company logo on PDF records
- Sync through your own private iCloud
- £24.99 a year with a 7-day free trial for eligible new subscribers, or £74.99 once for lifetime access

No sign-up, no ads, no tracking. Works without an internet connection.

KnownGood is a record-keeping tool. It does not test, calibrate or sign off any instrument, and it does not replace a certificate from a calibration lab. Deciding whether an instrument is fit to use stays with you.

The yearly subscription renews automatically unless cancelled at least 24 hours before the end of the current period. Manage or cancel it in your App Store account settings.

From D4N LTD.

Independent app. Not affiliated with or endorsed by NICEIC, NAPIT or any assessment scheme.

Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ and https://d4n.io/projects/knowngood/terms/
Privacy: https://d4n.io/projects/knowngood/privacy/

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| KnownGood Pro | $24.99 | per year |

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| KnownGood Pro | $79.99 | one-time |


## Is KnownGood safe?

Not enough ratings yet to assess KnownGood.

## Is KnownGood legit?

KnownGood appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for KnownGood is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 1 release)

### 1.0.0 — 2026-11-02

No release notes.

## More apps by D4N LTD

- [StandbyCalc Battery Calculator](https://appshunter.io/ios/app/standbycalc-battery-calculator/id6761339878)
- [Laylo](https://appshunter.io/ios/app/laylo/id6761607186)
- [GroundPin: Utility Locator](https://appshunter.io/ios/app/groundpin-utility-locator/id6762096562)

All apps by D4N LTD: https://appshunter.io/developer/1212131887

---

*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-11-07.*