Disclaimer

The calculators on this site are working tools, not professional advice. This page explains exactly where that line falls, because on some of these pages the difference is a ramp somebody has to use or a pipe that has to drain.

What these calculators are

Every calculator here computes a stated formula and shows its working. The arithmetic is checked against published sources, and each page lists the references it lines up with. Where a page states a code figure, such as the 1:12 maximum running slope in the ADA Standards, that figure is quoted from the published standard and named on the page so you can go and read it yourself.

What they are not

A calculator does not know your site. It does not know your soil, your span, your local amendments, the year your jurisdiction adopted its code, or the inspector who will look at the work. Two projects with identical numbers can have different correct answers, and no tool on any website can tell them apart.

Nothing on this site is engineering advice, architectural advice, surveying advice, legal advice, or a substitute for a licensed professional. We are not your engineer, and using a calculator here does not create a professional relationship of any kind.

Where this matters most

• Accessibility work. A ramp that reads as compliant here can still fail an inspection. The ADA Standards, the IBC and your state and local amendments all apply, and they are not always the same. Have accessible construction reviewed by somebody qualified to sign for it.
• Structural work. Roof pitch, rafter length and cut length are geometry. Load, span, snow, wind, uplift and fastening are engineering. This site does the first and not the second.
• Drainage and sewer. Pipe fall figures follow published minimum slope guidance for the diameter given. Actual required fall depends on flow, material, cover, connection depth and your local plumbing code, which may set a different minimum than the general guidance shown.
• Highways and earthworks. Grade, cross slope and superelevation on public work are governed by the specification for that contract. Follow the specification, not a web calculator.

Mistakes

The calculators are tested and the content is checked, but this is software and it is written by people. If a result looks wrong, it may well be wrong. Tell us and we will look at it the same week: hello@slopecalculators.com. Corrections are made openly and the page footer records the date it was last updated.

Liability

You use these calculators at your own risk. To the fullest extent permitted by law, slopecalculators.com accepts no liability for loss, cost, damage, rework, delay or injury arising from reliance on any figure, statement or result produced by this site. If a result will be built, buried, inspected, or walked on by the public, have it checked by somebody who carries professional liability for that check. We do not.

Outside links

We link to standards bodies, textbooks and manufacturers where they support a statement on the page. We do not control those sites and we are not responsible for what they publish or for how they change after we link to them.