Digital spirit level or bubble: screen, light, or vial
Updated: 22 October 2026
You are setting a worktop or a stud, and the listing offers a digital spirit level or bubble, a beep, or a green light. You need to know whether that extra readout is a tighter measurement or only easier to catch when the vial is awkward to see. On our [magnetic spirit level](/hub/measuring-and-marking-tools/spirit-level-magnet) comparison, the amazon.co.uk listings cover Franklin's light-up bar and two LCD bars. A screen adds a number and, on one listing, a beep at level and plumb. A ±0.1° claim is coarser than a ±0.5 mm/m vial, and you stop if the screen and the bubble disagree. Peter F. used those UK listings and a published conversion table, with no lab test. A qualifying amazon.co.uk purchase can earn a commission at no extra cost to you.
You are setting a worktop or a stud, and the listing offers a digital spirit level or bubble, a beep, or a green light.
You are setting a worktop or a stud, and the listing offers a digital spirit level or bubble, a beep, or a green light. You need to know whether that extra readout is a tighter measurement or only easier to catch when the vial is awkward to see. On our magnetic spirit level comparison, the amazon.co.uk listings cover Franklin's light-up bar and two LCD bars. A screen adds a number and, on one listing, a beep at level and plumb. A ±0.1° claim is coarser than a ±0.5 mm/m vial, and you stop if the screen and the bubble disagree. Peter F. used those UK listings and a published conversion table, with no lab test. A qualifying amazon.co.uk purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Length | Stated accuracy | Readout | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Grettz Grettz GL120 1200 mm | 1200 mm | Under 0.1° at 0°, 45°, and 90°; under 0.2° at other angles | Dual backlit LCD, top and side | 9.6 | about £155.99 | View offer |
| Alternative |  Franklin Sensors Franklin Sensors light level | 12 inch (30.5 cm) | n/a | Lights turn green at level or plumb; two bubble vials; no degree figure | 9.2 | about £24.58 | View offer |
| Alternative |  Huepar Huepar DL24 600 mm | 600 mm / 24 inch (listing dimensions 60 x 60 cm) | ±0.1° at 0° and 90°; ±0.2° at other angles; 0.05° resolution | LCD; degrees, percent, mm/m, or in/ft; beep at 0° and 90°; display flips | 7.8 | about £59.99 | View offer |
On this page
Three readouts, from a vial to an LCD
A vial shows the bubble between the marks when you can look straight at it. Franklin's 12-inch iLevel adds a green light at level or plumb and keeps two vials on a plastic body, listed at £24.58 with 4.6 stars from 2,418 ratings. The maker's page prints no degree tolerance. A PistonHeads thread asks what range counts as green, because that page leaves the band unpublished.
Huepar, at £59.99 with 3.9 stars from 21 ratings, shows degrees, percent, millimetres per metre, or inches per foot, and the listing says it beeps at 0° and 90°. The material field says ABS while the bullets say aluminium, so the body stays unresolved. Grettz, at £155.99 with 4.8 stars from six ratings, prints a dual LCD and degree claims. Its beep appears in a review, not in the bullets. On a ceiling batten you cannot sight, Franklin's lamp or Huepar's beep is the cue you use.
Why 0.1 degrees is coarser than 0.5 mm per metre
A tenth of a degree looks fine on a listing, and on these claims the millimetre line is the stricter one. Elesa-Ganter's table sets 0.1000° at 1.7 mm per metre. The conversion used here puts 0.5 mm per metre at about 0.03°, so a ±0.1° window allows about three times that slope. Huepar prints ±0.1° at 0° and 90°, and ±0.2° otherwise. Grettz prints under 0.1° at 0°, 45°, and 90°, and under 0.2° otherwise. Franklin prints no degree figure.
On a one-metre worktop, 0.5 mm of rise is the vial line and 1.7 mm is what 0.1° allows. A drawing that says 0.5 mm/m is not met by a ±0.1° badge. Keep any ±0.05° electronic claim off Huepar and Grettz, because neither listing prints it. Huepar can show millimetres per metre on the screen. If that figure and the bubble disagree, you stop.
When the screen and the bubble do not match
Huepar reviews in this folder say the bubble was more sensitive than the digits, that a small move left the screen unchanged, and that the display was way off for shuttering. The screen can sit still after the vial has moved. If they disagree, stop, and do not average the two readings. Set the bar on a surface you already trust and follow the vial until they agree. A stalled digit on a shutter is enough reason to abandon that cut.
Grettz has six ratings at 4.8 stars. Readers said the readings matched a trusted level and that the audio helped, and they called the bar pricey, with a screwed battery cover. Six reviews leave the printed "under 0.1°" line unproven as a general rule. Huepar claims IP54 and Grettz claims IP65. Both stay claims, because we ran no water test and opened no certificate. The flip test is on the how to use a magnetic spirit level page.
Cells, cases, and when the vial is enough
A screen is only as current as its cells. Franklin takes one AA cell, and you supply it. One review said the packaging implied a battery the carton lacked, and another reported LEDs that had failed, which leaves the two vials. Grettz names 2 × AAA in the bullets and omits them from the included-components line. One review says the cells were supplied, and a carry case is listed. Huepar's battery type is n/a, so the size stays unknown until you open the compartment. Reviewers mention a fabric case.
Use the vial for a shelf, a short worktop, or a door lining you can see in daylight. It needs no cell, though it is a weak choice overhead or in a dim room, where Franklin's light or Huepar's beep is why you pay more. The vial is the readout when you can sight it, and a light or an LCD only when you cannot. Grettz suits that second case only if £155.99 and six ratings are acceptable, since its beep is a review comment. Length is in the magnetic spirit level buying guide.
Common questions
Is a digital level more accurate than a ±0.5 mm/m bubble?
On these printed windows, the vial line is tighter. A ±0.5 mm/m vial is about 0.03°, and Elesa-Ganter's table puts 0.1° at 1.7 mm per metre, about three times the slope. Huepar prints ±0.1° at 0° and 90° and ±0.2° otherwise. Grettz prints under 0.1° at 0°, 45°, and 90°, and under 0.2° otherwise. Franklin prints no degree. A screen still helps when you cannot see the vial.
What does 0.1 degrees mean in millimetres per metre?
Elesa-Ganter's table equates 0.1000° with 1.7 mm of rise over one metre. A ±0.1° claim allows about 1.7 mm per metre, which is wider than 0.5 mm per metre, or about 0.03°. If the drawing uses millimetres per metre, read that unit. Huepar can show it on the screen. Franklin's green light has no number, so this conversion does not apply to the lamp.
What should I do if the screen and the bubble disagree?
Stop, and do not average the two. Huepar reviews in this set say the bubble moved when the digits did not, and that the display was way off for shuttering. A calm number can still be wrong. Put the bar on a surface you already trust, or follow the vial, before you cut or fix to the disputed reading.
Does Franklin's green light show a degree?
It shows a colour, not a number. Franklin's page says green means level or plumb and prints no degree tolerance. The listing at £24.58, with 4.6 stars from 2,418 ratings, pairs the light with two vials. A PistonHeads thread asks the green range, and the maker does not state one. One review reported failed LEDs, so the vials are the backup when the lamp stays dark.
Which of these levels beeps at level?
Huepar's listing states a beep at 0° and 90°. That bar is £59.99, with 3.9 stars from 21 ratings. Grettz, at £155.99 with 4.8 stars from six ratings, mentions audio only in a review. The bullets name the dual LCD, degree claims, IP65, rare-earth magnets, and 2 × AAA cells. Franklin uses a green light. If you need a sound the listing itself promises, Huepar is the page that prints it.
When is a bubble enough on its own?
A bubble is enough when you can see the vial and you only need level or plumb. A shelf, a short worktop, or a door frame in daylight is that job. It needs no cell. Overhead or in poor light it is a weak choice, which is where Franklin's green light or Huepar's beep earns its price.
Related pages
Sources
Public UK sources used for this page. Shelf prices, stars and review counts are the amazon.co.uk figures for this set. The page score is the comparison score scaled to ten. This is not a laboratory test. Retrieved 22 October 2026.
- British Stainless Steel Association, magnetic properties of austenitic stainless steels (retrieved 22 October 2026)
- GOV.UK, electromagnetic interference sources (retrieved 22 October 2026)
- GOV.UK, laser radiation safety advice (retrieved 22 October 2026)
- Consumer Rights Act 2015, section 22 (retrieved 22 October 2026)
- OX Tools, how to check the accuracy of a spirit level (retrieved 22 October 2026)
- Armstrong Cheshire, how to calibrate a spirit level (retrieved 22 October 2026)
- Blueperry, Stabila 96-M-2 magnetic spirit level 60 cm (retrieved 22 October 2026)
- HSE HSG281, managing work with an implanted medical device (retrieved 22 October 2026)