Plumb: Bubble Spirit Level
Angle Finder, Slope & Surface
Only for iPhone
Free · In‑App Purchases
iPhone
Plumb is a precision bubble level that looks and feels like the real thing — machined bezel, genuine spring-damper physics, and a vial with real fluid optics.
Check level, plumb, any angle, or a whole surface at once. No ads. No account. No tracking.
The bubble moves with genuine spring-damper physics. The bezel looks like machined rubber. The vial renders with real fluid optics. When you hit level, the screen flashes, a tone fires, and the phone vibrates — all at once, so you can feel it without looking.
LEVEL TAB
The main vial reads roll in portrait or landscape. Lock orientation from the toolbar — portrait, landscape left, landscape right, or auto. Lock a reading to free up your hands. Calibrate to any known flat surface with one tap.
SURFACE TAB
A bullseye level checks both axes simultaneously. Perfect for countertops, appliances, equipment, and anything that needs to be flat in every direction at once.
ANGLE TAB
Dial in any target angle — 45°, 22.5°, a custom pitch, or a grade percentage — and get live feedback as you approach it. Great for trim work, ramps, crown molding, roofing, and drainage slopes.
SIX DISPLAY MODES
Choose how angles are shown — degrees, percentage, mm/m, pitch (X.X:12), or in/ft. Each tab has its own independent display mode. Tap any readout to cycle through options.
WORKS EVERY WAY YOU HOLD IT
Portrait, landscape left, landscape right, face-up, face-down — Plumb reads correctly in every orientation automatically. No mode to switch, no setup required.
HOLD
Freeze any reading with one tap, one volume button press, or the Action button. Press again to release. A haptic confirms when hold is activated or released.
FEEDBACK THAT KEEPS UP WITH YOU
Tone — pitch rises as you approach level, fires a clean confirm when you hit it
Flash — the camera flash pulses on level, useful in dark spaces
Haptic — a firm tap through the phone the moment you're on target
NIGHT MODE
A dedicated all-black theme with deep red vial and glow ring. Designed for attics, crawl spaces, and low-light conditions where a bright yellow screen is a liability.
SIX THEMES
Yellow, Red, Black, Sky Blue, Orange, and Night mode.
CALIBRATION
Per-orientation calibration profiles. Calibrate portrait, landscape left, landscape right, and flat independently. Reset any profile individually or all at once.
NO ADS. NO TRACKING.
Plumb does one thing and does it right. Nothing phones home. Nothing asks for your email.
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://nationaltoolworks.com/apps/plumb/privacy
• Introducing Plumb Pro: AR camera mode, colour themes + night mode, trade units (%, pitch, mm/m, in/ft), adjustable tolerance, and level alerts — free for 14 days, then $9.99/year
• Early user? Everything stays free for you, forever — thanks for being here first
• Settings redesigned
The developer, National Tool Works LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- National Tool Works LLC
- Size
- 1.9 MB
- Category
- Utilities
- Compatibility
Requires iOS 16.0 or later.
- iPhone
Requires iOS 16.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Plumb Pro $9.99
- Copyright
- © 2026 National Tool Works LLC