A leveler that runs in your browser, with no app to install.

A leveler is any tool that tells you whether a surface is flat, or that makes it flat. In measuring, it means a spirit level: a sealed glass vial of liquid with one air bubble that climbs to the highest point of the tube. The word is also used for products that do the flattening, such as a self-levelling floor compound, a ladder foot, or a loading-dock plate. LevelerPro is the measuring kind, running as a web page instead of a bar of aluminium.

Put the level on the surface and look at the two lines etched in the middle of the vial, called the gate. If the bubble sits evenly between them, that axis is level. If it drifts to one side, that side is the high side, because the bubble always climbs toward the raised end, because air is lighter than the liquid around it. Shim the low end until the bubble centres. For a reading you can trust, note it, turn the level end-for-end in the same spot, and read again: a true surface gives the same answer both ways.

Yes. Every modern phone contains an accelerometer that measures the direction of gravity, which is the same physical quantity a spirit vial responds to. Lay the phone flat, screen up, and it can resolve tilt to roughly a tenth of a degree. Two cautions: the sensor ships with a small fixed bias, so calibrate it once on a surface you trust, and phone cases with raised lips or camera bumps will rock the device and spoil the reading. Take the case off for anything precise.

Open a browser-based level such as this page, with no install and no account. On a laptop or desktop there is no tilt sensor to read, so the tool falls back to a drag preview you can use to see how the vials behave; the live reading needs a device that actually has an accelerometer. Because the maths runs locally in JavaScript, the page works without a network round-trip once loaded, and no measurement is ever sent anywhere.

Open levelerpro.com on the phone, then rest the phone flat on the surface. On iPhone, tap Enable Motion Sensor and allow Motion & Orientation access when Safari asks. iOS only grants it after a tap, and only over HTTPS. Android grants it automatically. Tap Set Zero while the phone sits on a reference surface, then read the vial on the edge that runs along whatever you are checking. Add the page to your home screen if you want it to open like an app.

Judge one on four things rather than star ratings: can you calibrate it and clear that calibration; does it show real units such as degrees, percent slope and mm per metre; is it honest about accuracy instead of claiming a hundredth of a degree from a phone sensor; and does it work without demanding an account or your location. LevelerPro is free and needs no install, but the same checklist applies to any option, including the level built into iOS Measure.

A dock leveler is the steel plate at a loading bay that bridges the gap and height difference between a warehouse floor and a trailer bed so pallet trucks can drive across. A pit-mounted dock leveler sits in a recess in the dock floor; an edge-of-dock leveler bolts to the face of the dock and suits smaller height differences. It is loading equipment, not a measuring tool, though this page will read the slope of one, in mm per metre, to check it against the specified grade.

Sweep and vacuum the slab, then check where it actually needs filling: rest a phone level at several points to find the high spot, because you build depth from there. Repair holes and cracks, prime the surface with the primer that matches the compound, and dam any doorways or gaps so the mix cannot escape. Mix with clean water at the ratio on the bag, pour, and spread with a gauge rake to the depth you measured. Work in one continuous pour per area so wet meets wet.

Self leveler is the same product handled a little more carefully, because it flows on its own. Use cool clean water at exactly the ratio printed on the bag, because extra water weakens it and causes cracking, then mix two to three minutes with a paddle on a slow drill until there are no lumps. You then have a short working time, usually ten to twenty minutes, so mix only what you can pour in that window. Pour in ribbons, help it out with a gauge rake, and pass a spiked roller over it to release trapped air.

Most standard compounds are walkable in two to four hours and accept a floor covering after about 24 hours. Rapid-set products cut that sharply, often walkable in around an hour and tileable the same day. Full curing is slower than drying: moisture-sensitive coverings such as vinyl, resin or wood usually want several days and, on a fresh slab, a moisture test before you lay them. Depth, temperature and humidity all move these figures, so treat the bag as the authority.

Work from area times depth. Most compounds use roughly 1.5 to 1.7 kg of powder per square metre per millimetre of thickness, so a 20 kg bag covers about 4 m² at 3 mm, or about 2.5 m² at 5 mm. Measure the deepest point rather than the average, add ten per cent for waste, and remember most products have a minimum thickness, often 2 to 3 mm, below which they will not flow or bond properly. Coverage is printed on the bag; use it in preference to any rule of thumb.

A cake leveler is an adjustable wire that slices the dome off a sponge so layers stack flat. Cool the cake completely, and chill it briefly if it is crumbly. Set the wire to the height you want, stand the leveler on the work surface, and saw gently with a light back-and-forth motion rather than pressing down. Rotate the cake into the blade instead of forcing the blade through it. If your sponges keep doming unevenly, check the oven shelf is level before blaming the recipe.