Audited 05 Aug 2026·Last updated 08 Aug 2026·5 citations·Tier 1·0 uses

Foundation Footing Calculator

Foundation Footing Calculator: divide service load by locally approved allowable soil bearing pressure and show equivalent square area.

Foundation Footing Calculator

Required bearing area
30
Required bearing area under the page's named structural convention.
Continuous footing width before code minimums
1.5
Equivalent square footing width
5.4772

Background.

This foundation footing page is built to divide service load by locally approved allowable soil bearing pressure and show equivalent square area. Bearing area is only one footing check; width must also satisfy structural load path and code minimums. The implemented convention is “required bearing area = service load ÷ locally approved allowable soil bearing pressure.”

The editable entries are service load carried by footing, locally approved allowable soil bearing pressure, continuous footing length. Use values from the document or measurement that governs this foundation footing question; the defaults are only the worked fixture below. Eccentricity, settlement, frost depth, reinforcement, sliding, uplift and actual geotechnical conditions require design. If that foundation footing condition is not true, choose a calculation that models the missing convention.

International Code Council, 2021 International Residential Code; footings, ventilation and residential systems documents the convention or governing rule used here. The foundation footing output is a transparent scenario under those facts: it does not manufacture an unentered market price, professional determination, carrier quote, legal eligibility finding or locally adopted code value.

What is foundation footing calculator?

Foundation Footing is the relationship behind this decision: bearing area is only one footing check; width must also satisfy structural load path and code minimums. On this page it means required bearing area = service load ÷ locally approved allowable soil bearing pressure. Eccentricity, settlement, frost depth, reinforcement, sliding, uplift and actual geotechnical conditions require design; that is the line between the reported quantity and a broader structural analysis.

How to use this calculator.

  1. Confirm that “required bearing area = service load ÷ locally approved allowable soil bearing pressure” matches the foundation footing convention you need.
  2. Replace the fixture values for service load carried by footing, locally approved allowable soil bearing pressure, continuous footing length with dated values from the governing record.
  3. Keep all currencies, measurement units and time periods on the same basis before calculating.
  4. Read required bearing area together with this boundary: Eccentricity, settlement, frost depth, reinforcement, sliding, uplift and actual geotechnical conditions require design.

The formula.

required bearing area = service load ÷ locally approved allowable soil bearing pressure
serviceLoadPounds · Service load carried by footingallowableSoilBearingPsf · Locally approved allowable soil bearing pressurefootingLengthFeet · Continuous footing length

The calculation uses required bearing area = service load ÷ locally approved allowable soil bearing pressure. In this foundation footing model, the entered terms are service load carried by footing, locally approved allowable soil bearing pressure, continuous footing length. Bearing area is only one footing check; width must also satisfy structural load path and code minimums, which is why the relationship is presented under this name rather than as a universal alternative. Eccentricity, settlement, frost depth, reinforcement, sliding, uplift and actual geotechnical conditions require design. Calculations keep full decimal precision through the relationship and round only the returned display values.

A worked example.

Example

Enter the example facts as Service load carried by footing = 60,000; Locally approved allowable soil bearing pressure = 2,000; Continuous footing length = 20. The formula “required bearing area = service load ÷ locally approved allowable soil bearing pressure” then reconciles them to Required bearing area = 30; Continuous footing width before code minimums = 1.5; Equivalent square footing width = 5.4772255751. You can audit the 30 primary result by carrying the raw products, ratios and limits through to the final line before formatting. Bearing area is only one footing check; width must also satisfy structural load path and code minimums. Eccentricity, settlement, frost depth, reinforcement, sliding, uplift and actual geotechnical conditions require design.

allowable Soil Bearing Psf2,000
service Load Pounds60,000
footing Length Feet20

Frequently asked questions.

What exactly does the required bearing area represent?
For Foundation Footing, it represents the result of required bearing area = service load ÷ locally approved allowable soil bearing pressure under the entered facts. Bearing area is only one footing check; width must also satisfy structural load path and code minimums; the 30 fixture should be read on that basis.
Which foundation footing convention does this page choose?
It chooses “required bearing area = service load ÷ locally approved allowable soil bearing pressure.” That foundation footing variant is supported by International Code Council, 2021 International Residential Code; footings, ventilation and residential systems; a governing contract, policy, tax year or locally adopted rule that specifies another treatment must take priority.
What is the easiest way to get this foundation footing result wrong?
Eccentricity, settlement, frost depth, reinforcement, sliding, uplift and actual geotechnical conditions require design. Check that foundation footing issue before interpreting the output or comparing it with another model.
Can the worked foundation footing example be checked without this site?
Yes. Use Service load carried by footing = 60,000; Locally approved allowable soil bearing pressure = 2,000; Continuous footing length = 20, follow required bearing area = service load ÷ locally approved allowable soil bearing pressure, and compare your final figures with Required bearing area = 30; Continuous footing width before code minimums = 1.5; Equivalent square footing width = 5.4772255751. Keep the foundation footing intermediates unrounded so formatting does not create a false difference.

References& sources.

  1. [1]International Code Council, 2021 International Residential Code; footings, ventilation and residential systems. Retrieved 2026-08-07. access: open unless marked otherwise.
  2. [2]International Code Council. 2024 International Residential Code (IRC). Retrieved 2026-08-07. independence: primary; access: open.
  3. [3]International Code Council. 2024 International Energy Conservation Code (IECC). Retrieved 2026-08-07. independence: primary; access: open.
  4. [4]U.S. Bureau of Labor Statistics. Producer price indexes. Retrieved 2026-08-07. independence: secondary-check; access: open.
  5. [5]National Association of Realtors. Research and statistics. Retrieved 2026-08-07. independence: secondary-check; access: open.

How this page was produced

Published by
Quanta Calculator
Primary sources
5 cited below
Method
required bearing area = service load ÷ locally approved allowable soil bearing pressure
Published
Last verified

Built with AI assistance and verified by automated tests against the cited sources — every worked example on this page is computed by the same code that runs the calculator. How we build and check calculators.

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