Fidamen

Convert Square Feet to Acres - Area Converter

This converter transforms area values expressed in square feet into acres and vice versa using the fixed, established conversion factor. It is intended for planners, homeowners, land managers, and anyone who needs a fast, authoritative area conversion.

The tool uses the standard relationship applied in U.S. land measurement and surveying practice. For legal surveys or boundary determinations, always rely on certified survey data and local cadastral rules; this converter is best for calculations, estimates, and administrative tasks.

Updated Nov 3, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 375e9355e28f • Reviewed by Fidamen Standards Committee

Interactive Converter

Convert between square foot and acre with precision rounding.

Quick reference table

Square FootAcre
1 ft²0 ac
5 ft²0.0001 ac
10 ft²0.0002 ac
25 ft²0.0006 ac
50 ft²0.0011 ac
100 ft²0.0023 ac

Methodology

The conversion is based on the internationally accepted definition that 1 acre equals 43,560 square feet. This factor is used directly—no approximation or intermediate unit conversions are required.

For conversions into metric units, the converter relies on the accepted equivalence 1 acre = 4,046.8564224 square metres when higher precision is required; that value is consistent with federal measurement references.

When presenting results, the tool follows common engineering practice for significant figures and allows users to round according to their reporting needs. For regulatory submissions, follow your agency's rules for rounding and accepted tolerances.

F.A.Q.

What is the exact conversion factor between square feet and acres?

One acre is defined as exactly 43,560 square feet. This is the standard factor used by federal and surveying authorities.

Is the acre an SI unit?

No. The acre is a non-SI customary unit of area commonly used in the United States and some other countries. For scientific work, use square metres (SI) or hectares; 1 acre = 4,046.8564224 square metres.

Can I use this converter for legal land surveys or property deeds?

This converter is suitable for calculations and estimates. For legal descriptions, boundary surveys, or deed preparation, rely on a licensed land surveyor and official cadastral records. Follow local jurisdiction rules for measurement tolerances and certified instruments.

How should I handle rounding and significant figures?

Choose rounding based on the use case: engineering designs typically keep 3–6 significant figures, while high-level planning may use 1–2. For regulatory filings, follow the specific agency or municipal rounding policy. When in doubt, preserve more digits and document the rounding method.

Why is the factor 43,560?

The value comes from historical land-measurement conventions in which an acre was standardized as a rectangle 660 feet by 66 feet, giving 43,560 square feet. Modern definitions use that exact numeric equivalence.

How do I convert very large or very small areas without losing precision?

Work in scientific notation or convert to a larger unit (acres or hectares) to avoid floating-point rounding. If you require sub-square-foot precision, use high-precision tools or software that support extended decimal places and reference authoritative unit definitions.

Sources & citations

Further resources

Versioning & Change Control

Audit record (versions, QA runs, reviewer sign-off, and evidence).

Record ID: 375e9355e28f

What changed (latest)

v1.0.0 • 2025-11-03 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Public QA status

PASS — golden 25 + edge 120

Last run: 2026-01-23 • Run: golden-edge-2026-01-23

Engine

v1.0.0

Data

Baseline (no external datasets)

Content

v1.0.0

UI

v1.0.0

Governance

Last updated: Nov 3, 2025

Reviewed by: Fidamen Standards Committee (Review board)

Credentials: Internal QA

Risk level: low

Reviewer profile (entity)

Fidamen Standards Committee

Review board

Internal QA

Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person

Semantic versioning

  • MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
  • MINOR: New features or fields that do not change existing outputs for the same inputs.
  • PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.

Review protocol

  • Verify formulas and unit definitions against primary standards or datasets.
  • Run golden-case regression suite and edge-case suite.
  • Record reviewer sign-off with credentials and scope.
  • Document assumptions, limitations, and jurisdiction applicability.

Assumptions & limitations

  • Uses exact unit definitions from the Fidamen conversion library.
  • Internal calculations use double precision; display rounding follows the unit's configured decimal places.
  • Not a substitute for calibrated instruments in regulated contexts.
  • Jurisdiction-specific rules may require official guidance.

Change log

v1.0.0 • 2025-11-03 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: a8b327789f24