Dock Size Calculator

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Enter your dock dimensions and state to instantly see total square footage, whether you meet common exemption thresholds, and how Florida's 10-to-1 shoreline preemption rule affects your project.

This calculator provides general guidance based on publicly stated exemption thresholds. Actual permit requirements depend on your specific water body, location, and local rules. Always verify with your state agency before building.

Enter Your Dock Dimensions

The main access walkway from shore to platform
End platform or T-head dimensions
Total Overwater Area
square feet
Max Width (ft)
Walkway Area (sq ft)
Platform Area (sq ft)

Use Permit Navigator → Download Prep Checklist →

What We Check and Why

Total Square Footage

Total overwater area is the sum of your walkway area plus your platform/end deck area. Florida's DEP exemption is based on this total. We calculate it from your dimensions — walkway L×W plus platform L×W.

Florida's 10-to-1 Shoreline Rule

Florida limits how much sovereign submerged land you can preempt (occupy with your dock) based on your upland shoreline ownership. The rule: 10 square feet of preemptable area per linear foot of shoreline. A property with 75 linear feet of shoreline can support up to 750 square feet of dock — even though the state exemption threshold is 1,000 square feet. The 10-to-1 calculation often sets a stricter limit than the 1,000 sq ft cap for smaller waterfront lots.

Minnesota's 8-Foot Width Rule

Minnesota DNR's no-permit threshold is based on width, not total square footage. Every section of the dock must be 8 feet or less. A 4-foot walkway with a 10-foot end platform fails the test — the platform is wider than 8 feet. We check your maximum width against the 8-foot standard.

Michigan's 6-Foot Width Rule

Michigan EGLE's Part 301 inland lake exemption requires every section of the dock to be 6 feet wide or less, plus seasonal removal before December 1. We check your maximum width against the 6-foot standard for inland Michigan lakes.

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