Is there an Omni Calculator alternative for concrete, roof pitch and gravel?
Published · By Sai Nath
For building maths, MeisterCalc is an Omni Calculator alternative: free concrete and roof pitch calculators on this site, and an Android app that works offline. Omni's concrete calculator covers six shapes with waste and cost per bag (checked 1 November 2026); MeisterCalc counts bags from each maker's data sheet, in millimetres first.
We make MeisterCalc, so read this with that in mind. Every fact about Omni Calculator comes from its own pages and its Google Play listing, read on 1 November 2026 and linked where the fact appears. MeisterCalc's figures come from its own formula code. Where we work an Omni sum, we work it by hand from the method its page describes and say so; we did not copy its result screens. Checked on 1 November 2026.
What does Omni Calculator offer builders?
A general calculator site with a construction section. Its Android app, “Omni Calculator: 3700+ Tools”, describes itself as “the official mobile app for the Omni Calculator website” and lists construction and home calculators “for gravel, tile, concrete, paint, stairs, roof pitch, board feet, bricks, flooring, sand” among many other topics. On 1 November 2026 its Google Play listing showed 10K+ downloads and 3.7 stars from 45 reviews, updated on 21 October 2026. This page compares three of its building calculators: concrete, roof pitch and gravel.
MeisterCalc is narrower. It is an Android app with 16 building calculators, and this site has free web calculators for building maths. See all the construction calculators.
How do Omni and MeisterCalc compare?
Omni does more shapes, costs and units per field; MeisterCalc counts bags from named products, adds the roof overhang, and works offline in an app. Checked on 1 November 2026: Omni facts are from the pages linked in each row; MeisterCalc facts are from its code and its own pages.
| Checked on 1 November 2026 | ||
|---|---|---|
| What you get | Omni Calculator | MeisterCalc (free web calculators, and the app) |
| What it is | Thousands of calculators on many topics, on the web and in an Android app (source) | Free building calculators on this site, and an Android app with 15 (Android 7.0 or later) |
| Price | Free on the web; the app is free to install, with no in-app purchases label on its listing (source) | Web calculators free. In the app, Concrete, Stairs and Check Square are free; the other 13, including Pitch and Gravel, unlock with a weekly subscription (3-day free trial) or a one-time lifetime unlock |
| Concrete shapes | Slab, wall, footer, column, curb and gutter barrier, stairs (source) | Web: slab, strip footing, post holes. App Concrete: Slab and Holes |
| Concrete bags | By weight: volume × density ÷ bag size, plus your waste (source) | Web: by the yield on the maker's data sheet, for five named metric products or 40, 60 and 80 lb QUIKRETE bags. The app gives m³ and litres, no bag count |
| Waste | A waste % you enter; its page says contractors “usually assume 5-10%” (source) | The order figure always adds 10%. The app's cost section has a 0 to 30% wastage slider |
| Concrete cost | Cost per bag gives cost per slab, per unit area, per unit volume and total (source) | Web: your price per m³ or per bag of the chosen product, with and without the 10% extra. App: price per m³ gives Total Cost and Cost + waste. No cost per slab or per m² |
| Units | Any field can switch unit by “unlocking the field (the padlock button)” (source) | Web: metric or US for the whole form. App: millimetres by default, feet and inches in Settings; volumes in m³ (and litres for a slab) |
| Roof pitch | Any two of rise, run, rafter length, pitch in degrees, % or x:12 (source) | App Pitch: any two of rise, run, X/12, angle and % grade; the rafter line is a result, not an input. Web: one pitch value or a rise and run, plus a level overhang |
| Gravel | 16 gravel types or your own density (default 1680 kg/m³); area or length × width; works back from a weight to a depth; no waste field (source) | App Gravel: length, width, depth and density (default 1500 kg/m³, any value from 100 to 5000); volume, tonnes and an order figure with 10% added; optional price per tonne. No free web gravel calculator |
| Sources shown | Concrete cites the American Concrete Institute's slab guide (source); gravel cites an FHWA gravel roads manual (source) | Web concrete cites each bag maker's data sheet |
| Without a signal | Not stated on its listing (source) | The app works offline: every calculation runs on the phone |
How does the Omni concrete calculator work?
You pick a form, enter its sizes and how many, then a density, a bag size, a waste figure and a cost per bag. The forms are Slab, Wall, Footer, Column, Curb/Gutter Barrier and Stairs (Omni concrete calculator). It counts bags by weight. In its words, you “Determine the weight of all of those elements — this is how bagged concrete is sold”, then “Provide the size of the bag” and finally “the waste ratio”.
Its own example takes four elements of 3 × 3 × 3 ft, 4 cubic yards in all, at 150 lb per cubic foot in 60 lb bags: 16,201.03 lb of concrete, and with 5% waste, “We need 284 bags of concrete” (Omni concrete calculator). Its page says “All dimensions are given in feet by default”, and each field can be switched to another unit.
MeisterCalc counts bags the other way round: from the yield the bag maker prints on its data sheet. The free concrete calculator does slabs, strip footings and post holes in metric or US units, always adds 10% to order, and counts bags of Boral, Cement Australia, Dricon and Heidelberg Materials mixes, or 40, 60 and 80 lb bags from the QUIKRETE data sheet. It also has optional cost and slab rebar sections. Concrete in the app is free: Slab or Holes, with the volume in m³ (litres too for a slab) and an Order (+10%) figure, and an optional price per m³ for the cost.
Worked example: a 3600 × 2400 × 100 mm slab
A 3.6 m × 2.4 m shed slab, 100 mm thick, in MeisterCalc's free concrete calculator (the app's Concrete gives the same volumes):
- Volume: 3.6 × 2.4 × 0.1 = 0.864 m³, which is 864 litres.
- To order, with 10% added: 0.864 × 1.10 = 0.9504, shown as 0.950 m³.
- Bags: the order volume × the maker's bags per m³, rounded up to a whole bag. For Boral Concrete Mix, 20 kg, at 108 bags per m³: 0.9504 × 108 = 102.6, so 103 bags.
The same 0.9504 m³ in the other products the calculator lists, from each maker's stated yield as cited in how many 20 kg bags make a cubic metre:
- Cement Australia PROStrength Extra Strength Concrete Mix, 20 kg, about 110 per m³: 0.9504 × 110 = 104.5, so 105 bags (data sheet, PDF).
- Dricon HandiCrete, 25 kg, 0.010 m³ a bag: 0.9504 ÷ 0.010 = 95.0, so 96 bags (data sheet, PDF).
- Heidelberg Materials 40N Concrete, MaxiPack20, 0.008 m³ a pack: 0.9504 ÷ 0.008 = 118.8, so 119 packs (data sheet, PDF).
The same slab by Omni's weight method, worked by hand from the method its page describes: with 150 lb per cubic foot, the density its page names (about 2,403 kg/m³), 20 kg bags and 10% waste, 0.864 × 2,403 × 1.10 ÷ 20 = 114.2, so 115 bags. That is 12 more than Boral's sheet. The weight method treats each 20 kg bag as 20 kg of concrete at 2,403 kg/m³, about 8.3 litres; Boral's sheet says a bag makes 1 ÷ 108 m³, about 9.3 litres.
To make the weight method agree with a bag's stated yield, enter a density of bag weight × bags per m³. For Boral's 20 kg mix that is 20 × 108 = 2,160 kg/m³, and then 0.864 × 2,160 × 1.10 ÷ 20 = 102.6, so 103 bags, the data-sheet figure. Omni's page invites this: “Check if the density of the concrete from a particular producer is the same as the default value” (Omni concrete calculator). Read your own bag before you buy; yields differ between products.
How does the Omni roof pitch calculator compare?
Both turn a rise and run into every form of pitch and a rafter length. Omni takes any two of Rise, Run length, Rafter length, Roof pitch in degrees, in % and as x:12 (Omni roof pitch calculator), so you can start from a rafter you have already measured. Its worked example uses a 6 m run and a 1.5 m rise: rafter = √(1.5² + 6²) = √38.25 = 6.18 m, pitch 25%, 14° and 3:12 (its page).
The same roof in MeisterCalc's free roof pitch calculator, rise 1500 mm and run 6000 mm:
- Slope: 1500 ÷ 6000 = 0.25, so 3 in 12 (0.25 × 12), 14.04° (arctan 0.25) and 25%.
- Slope factor: √(1 + 0.25²) = 1.0308.
- Rafter line to the wall line: 6000 × 1.0308 = 6184.7 mm, Omni's 6.18 m.
- With a 450 mm level overhang: (6000 + 450) × 1.0308 = 6648.5 mm. Omni's roof pitch page has no overhang field, so you would add it yourself.
Pitch in the app (paid) takes any two of Rise, Run, Pitch (X/12), Angle and % Grade in ten modes. For Rise + Run with these figures it shows Pitch 3", Angle 14.04°, % Grade 25.00%, Slope Ratio 0.2500 and Hypotenuse 6184.7 mm. It doesn't take a rafter length as an input. For the theory, see rafter length from pitch and span.
What about the Omni gravel calculator?
The maths is the same; the default density is not. Omni starts at “1680 kg/m³ or 105 lbs/ft³”, offers 16 gravel types plus a custom density, takes an area or length × width, and can work backwards from a weight to the depth it covers (Omni gravel calculator). Its example path, 5 m × 1 m × 15 cm, needs 0.75 m³, “which weighs 1.26 tonnes”. It has no waste field; its page says to “buy some extra material”.
Gravel in the MeisterCalc app (paid) starts at 1500 kg/m³, and you can type any density from 100 to 5000. For the same path it shows Volume 0.750 m³, Weight 1.125 t and Order (+10%) 1.238 t. Set the density to 1680 and it shows 1.260 t, Omni's figure, and an order of 1.386 t. Neither default is your gravel: ask the supplier for the density of what they deliver. The sums are in how much gravel do I need and cubic metres to tonnes.
When is Omni the better pick?
- Walls, footers, columns, curb and gutter, or concrete stairs. Omni has six named concrete forms (concrete calculator); MeisterCalc names slab, strip footing and holes.
- Costing a pour by the bag. Omni turns a cost per bag into cost per slab, per unit area, per unit volume and total, with your own waste % (concrete calculator).
- Mixed units. Any field can switch unit with its padlock (concrete calculator), so a length in feet and a depth in millimetres can sit side by side.
- Starting from a rafter length. Omni's roof pitch calculator takes rafter length as one of its two inputs (roof pitch calculator).
- Gravel by type, or backwards from a load. Pick from 16 gravel types, or enter the tonnes you can get and read the depth (gravel calculator).
- Everything else. Omni's app lists calculators well beyond building, from finance to health (Google Play listing).
When is MeisterCalc the better pick?
- Bags of the product you are buying. The free concrete calculator uses the yield on the maker's data sheet for Boral, Cement Australia, Dricon and Heidelberg Materials mixes, and QUIKRETE bags in US units.
- On site with no signal. The app works offline, and Concrete, Stairs and Check Square are free in it.
- Metric trade work. Millimetres are the default; X in 12 is also shown to the nearest 1/16, and the roof calculator adds the eaves overhang to the rafter line.
- The rest of the job. Stairs, Check Square, Decking, Dumpy Level and 11 more building calculators sit in one app, each with a live diagram.
Questions people ask
Is Omni Calculator free?
The calculators on its website are free to use, and its Android app is free to install, with no in-app purchases label on its Google Play listing (checked on 1 November 2026).
Is there an Omni Calculator app?
Yes, on Android: “Omni Calculator: 3700+ Tools”, which calls itself the official app for the website (Google Play).
What density should I enter for bagged concrete?
If a calculator counts bags by weight, use the bag's weight × the bags per m³ on its data sheet: 20 × 108 = 2,160 kg/m³ for Boral's 20 kg Concrete Mix. Then the weight method and the yield agree. More in bags of concrete per m³.
Can MeisterCalc do walls and columns?
Not by name. A wall or square footing is a rectangular block, so Slab works with length, height and thickness. A round column is a cylinder, so Holes works with its diameter and height. Kerbs, gutters and concrete stairs need a sum by hand.
Does MeisterCalc work out the cost?
Yes. The free concrete calculator takes your price per m³ or per bag of the product you picked and gives the cost with and without the 10% extra. In the app, enter a price per m³ in Concrete, or per tonne in Gravel, Soil and Asphalt, and it shows Total Cost and the cost with a wastage % from 0 to 30. Neither breaks the cost down per slab or per m² as Omni does.
What are the limits of this comparison?
- Omni facts are what its own pages and Google Play listing say, checked on 1 November 2026. The Omni sums on this page are our hand working of the method its page describes, not copies of its results.
- Bag yields are each maker's figures for its own product, as cited in our concrete calculator. Other products differ; read the bag.
- Ratings, install counts and features change. Check the listing before you rely on them.
Checked on 1 November 2026. Spotted something out of date? Write to meruappsdev@gmail.com.
Sources
- Omni Calculator: Concrete Calculator (forms, weight method, example, waste, costs, units, source)
- Omni Calculator: Roof Pitch Calculator (inputs and worked example)
- Omni Calculator: Gravel Calculator (types, default density, example, reverse use)
- Omni Calculator: 3700+ Tools on Google Play (description, downloads, rating, update date)
- Boral Concrete Mix data sheet, Cement Australia PROStrength (PDF), Dricon HandiCrete (PDF), Heidelberg Materials 40N (PDF), as cited in our concrete calculator
- QUIKRETE Concrete Mix data sheet (PDF), for the 40, 60 and 80 lb bag yields in US units
Concrete in MeisterCalc
Concrete (Home ▸ Concrete) works out a slab from length, width and depth, or post holes from diameter, depth and count, in m³ (and litres for a slab) with 10% added to order, and draws the pour as you type. It is free, with Stairs and Check Square, and runs on Android 7.0 or later. Pitch, Gravel and the other paid calculators unlock with a weekly subscription that starts with a 3-day free trial, or with a one-time lifetime unlock; Google Play shows the prices in your currency.