Free roof surface calculation software: comparison of tools and verification test

A free roof surface calculation software exists for almost every need, but none of them does everything. An online calculator transforms already known dimensions into m²; a PDF reader measures a plan at scale, at the office. To measure the sections of a PDF plan on iPhone, iPad or Android, a measuring app like MeasureAll calculates the surface with the slope you enter, and tries it on a provided sheet. The right choice therefore depends on the data you have available, and what «free» really means.

This page compares the tools available in October 2026, explains the limitations of their free version, and offers a simple test to check a tool before using it for a quote.

Free roofing calculation software: which tool for which need?

Before choosing a free roof calculation software, start with what you have at hand. A tool does not convert one data into another: a calculator does not read a plan, and a plan viewed from above does not give the slope.

You have the option of	Adapted tool	What you get	What remains to be verified
Dimensions and slope already known	Calculation of the roof surface area	Calculated inclined surface	Accuracy of entered coordinates, slopes, unit of slope
Scale PDF plan	PDF reader with measurement, or measuring app	Lengths and areas indicated on the drawing	Calibration, slope of each panel, version of the plan
Geometry and tile model	Quantitative of a manufacturer	Estimated list of products from its range	Pureau, accessories, packaging
Only an address	Online card	View of the Emprise from the air, in projection	Unfamiliar slope, edges, precision of the ground

For an individual who wants to check a quote, a calculator often suffices. For a contractor who estimates several jobs per week based on the plans received, the question becomes one of measurement: measuring quickly and in a verifiable manner the sections, linear distances, and slopes indicated on the plans.

Comparison of free, freemium, and trial tools

The observations below were noted on October 11, 2026, on the publishers' pages, without subscription. They describe what each page advertises, not a test of each calculation engine.

Tool	Type	Observed free of charge	Measurement on a PDF	Slope	Main limit
Organilog	Web calculator	Free access announced	Not observed	Seizure	Dimensions to be provided; indicative material ratios
ArtisanOX	Web calculator	Free tool announced, no account required	Not observed	Seizure	Dimensions to be provided; free use of the management platform expires on 30/09/2026
Tools for work	Web calculator	Free access announced	Not observed	Seizure	Dimensions to be provided by yourself
Acrobat Reader	Desktop PDF reader	0 €	Yes, if the PDF allows it	To be applied yourself	Projection surfaces only
Foxit PDF Reader	Desktop PDF reader	0 €	Yes, with calibration, if the PDF allows it	To be applied yourself	Recorded measurements on computer, not on the mobile app
PDF-XChange Editor	Windows PDF Editor	Free measurements and calibration	Yes	To be applied yourself	Some paid features, with a watermark without a license
cartes.gouv.fr	IGN online map	Free	No	No	Obtained in projection; the measured angle is an azimuth
MeasureAll	iOS and Android metering application	A complete dossier offered, then a subscription	Yes, with calibration	Reported by the user	Plan measure; list of tiles to be prepared with the manufacturer's data sheet

The three calculators, those from Organilog, ArtisanOX and OutilsTravaux, meet the same request: you enter lengths, widths, overhangs and slopes; they return an inclined surface. They do not measure anything themselves. If your measurements are incorrect, their result is incorrect as well.

PDF readers measure a plan in the office. Acrobat Reader It offers distance, perimeter and area, but Adobe specifies that the author of the document must have authorized these measures for the free reader; the Documentation for Foxit PDF Reader reports a comparable reservation. Foxit PDF Reader and PDF-XChange Editor They also allow you to calibrate the scale; the latter is only available in Windows. All of them measure what is drawn: on a plan of the roof seen from above, this is the projection. The slope remains to be applied separately, panel by panel.

Online maps give a first idea of the extent of the impact. cartes.gouv.fr indicates that its angle tool measures an orientation relative to North, which is not a slope, and the help of Google Earth Reminds that its web-based measurements do not take altitude changes into account. A surface seen from the sky is therefore not the surface of an inclined roof.

Other tools complement this panorama without replacing it. At least one publisher is announcing a roofing software that imports a plan and manages slopes per panel, with free-of-charge conditions to be verified. The quantity data from manufacturers, such as the quantitative study by Edilians, reserved for professional accounts, starts from a geometry already known. As for free-of-charge quote software, they often limit the volume: the Synobat Starter offer, for example, announces 3 quotes and 3 invoices per month. None of these tools measures the roof for you.

Free, freemium, trial: what «free» means

The term covers at least six different situations: a completely free software, limited free features, a free trial, a few days of use, a demo version, and a promotional offer. A public calculator is included in the first; a freemium PDF editor in the second; MeasureAll in the third, with a complete dossier offered to try measuring on a real project, then a subscription in the app.

Before making a comparison, please read the terms: duration, number of projects, blocked functions, watermark, export. An outdated offer does not prove lasting free of charge: the page for ArtisanOX still showed free of charge for its management platform in October 2026, when its validity expired on September 30.

What a free tool should allow you to control

Regardless of the tool, the calculation is based on the same geometry. The surface area of a flat slope is equal to its horizontal projection, including any overhangs, multiplied by a slope coefficient:

Inclined surface = projection × √(1 + (slope in % ÷ 100)²), or projection ÷ cos(angle)

A good tool, whether free or not, should therefore allow you to master four points:

• the unit of slope : 45% and 45° do not give the same surface at all;
• a slope per panel, Because a main body and an extension do not always have the same shape;
• the edges, counted only once, depending on whether they are recorded horizontally or along the ramp;
• the number of sheets without hidden surcharge With identical pitch and slope, a four-slatted roof has the same surface area as a two-slatted roof, even though there are more cuts in the latter.

If the slope is not marked, it is calculated using the elevation difference and the horizontal distance: our article on the’application to calculate a slope explains how. The complete method, with the two- and four-panel roofs, the corbels, the ribs and the openings, is included in our guide for calculating the roof surface area.

Check a free software with a simple example

Before relying on a tool for a quote, test it on a case you know the answer to. Let’s take a house whose exterior walls measure 10.40 × 8.80 m, with horizontal overhangs of 0.40 m on all four sides and a two-sloped roof at 45%.

1. Roof overhang included: 11.20 × 9.60 = 107.52 m².
2. Slope coefficient: √(1 + 0.45²) = 1.096586.
3. Inclined surface: 107.52 × 1.096586 = 117.90 m².
4. Control by the ramp: width of 4.80 m, gradient of 4.80 × 0.45 = 2.16 m, ramp length √(4.80² + 2.16²) = 5.2636 m, that is 2 × 11.20 × 5.2636 = 117.90 m².

The results are rounded to the hundredth, based on non-rounded calculations. Enter the same data in the tested software. A difference of less than 0.1 m² is due to rounding; beyond that, the displayed result often tells you what the tool did:

Displayed result	What he reveals
152.06 m²	The slope was read in degrees: 107.52 ÷ cos(45°)
100.36 m²	The edges have been forgotten: 10.40 × 8.80 × 1.096586
235.81 m²	The surface was counted twice, once per panel.
129.70 m²	A 10% margin was added without being displayed

The same test applies to a 45% pitched roof with the same area: the answer remains 117.90 m². A tool that systematically adds 10 to 15% for four pitches also applies a margin, not a geometric rule. Some online tables also display surfaces exceeding the effect of the slope alone, without giving the reason. Before relying on them, recalculate a line using the coefficient: 50 m² of projection at 30% yields 52.20 m².

Test the slope by panel as well. For a main projection area of 60 m² at 30% and an extension of 40 m² to 60%, the total is 60 × 1.0440 + 40 × 1.1662 = 109.29 m². A tool that only accepts a slope for the entire roof will require you to perform two calculations.

For a tool that measures a PDF, the test first focuses on the scale. A plan exported or printed at 97% of its size is measured at the advertised scale, losing 3% in each length and 5.91% in each area, since 0.97 × 0.97 = 0.9409 and 1 − 0.9409 = 0.0591. Always calibrate on a known scale, then check a second scale in the opposite direction.

Do you measure using PDF plans? Measure your sections on iPhone, iPad or Android with MeasureAll: a complete file is provided to try it out.

The criteria for choosing a roofing software, whether free or not

For occasional use, a free roof area calculation software is often sufficient. For professional use, compare the tools on the same plans and with the same grid:

• Calibration Does the tool adjust to a known scale for each page or area drawn at a different scale, and does it allow a second scale to be controlled?
• Slope Does he accept a staggered payment plan, and does he clearly display his commitment to unity?
• Hypotheses Are the edges, margins and rounded corners visible, or are they applied silently?
• Outtake Can you keep the history, name the measures and export them?
• Land Does it work on mobile devices, and without a network once the plans are loaded?
• Real cost : what is the price after the trial, including VAT or not, per user per year, and how to manage the licenses for a team?

Finally, test each candidate on a few representative plans from your projects: this is the only comparison that is valid for your company.

Application to calculate the roof surface: measure on a PDF plan with MeasureAll

MeasureAll is an application that calculates the roof area for those who work from the plans received in PDF format. It measures the pitches, linear areas and deductions on the plan, and calculates the roof area with the slope you enter, on iPhone, iPad or Android, at the office or on site.

1. Import and calibrate. You import the PDF of the roof plan and the cut, you calibrate each page to a known reference point, and then you check a second reference point.
2. Trace the sections. You draw the outline of each side, including the edges, on the roof plan.
3. Enter the slope. You indicate the slope of the panel, as read on the cut or in the description: the application takes this into account to calculate the inclined surface area.
4. Lift the shelves. You measure the eaves and guttering on the roof plane, and the eaves on the eaves or gable facade, because a top view shortens everything that is inclined. These lengths are used for accessories and gutters.
5. Classify and export. You name the measures, you group them by project, and you export them in a spreadsheet-readable format.

Once the plans are loaded, the survey also works offline. However, the app does not replace the entire chain. It works on a scale plan: a top view does not show the slope, and a photo taken from an oblique angle is not a plan. The list of tiles and accessories still needs to be established with the manufacturer’s documentation. The accuracy of the result depends on the plan, its scale, and the care taken in the calibration.

Try the measurement on your own PDF plan: a complete file is provided. MeasureAll is available on the’App Store for iPhone and iPad, and on Google Play for Android smartphones and tablets. After this first subscription, the subscription is purchased in the app.

From square meters to tiles and a quote

A roof surface is not a one-size-fits-all solution. The number of tiles depends on the model chosen, its pitch and useful width, as specified by the manufacturer. The eaves and side tiles are counted from the linear units, the eaves according to the ventilation required; losses depend on the shape of the roof and the roofing system. No universal percentage applies.

The quote, on the other hand, includes the surfaces and the linear measurements according to the agreement made with the client. Keep a detailed record of your measurements, one panel at a time, so that you can justify them.

Several companies perform your roofing measurements? MeasureAll offers annual subscriptions for construction companies, with activation by company code, a single invoice, and transferable licenses. Equip your employees to prepare the floor plans: request a company quote.

Free roof surface calculation software: what you need to know

• Choose the tool based on your data: known dimensions, PDF plan, tile model, or simple address.
• A free roof area calculation software is most often a calculator or a PDF reader; a measuring application tries to work with a provided file: read its terms and conditions.
• Check the slope unit, the edges, and the absence of hidden margin with an example of which you know the answer.
• On a PDF, calibrate to a known value and check a second value.
• The surface serves as a base: tiles, accessories, losses, and quotes require additional data.

To measure your pitches and lines directly on the PDF plan, with the slope you enter, try MeasureAll: a complete file is provided, and then the subscription is purchased within the app.