What does Risk Category mean in ASCE 7-22?

Risk Category per ASCE 7-22 Table 1.5-1 classifies buildings by the consequences of failure: I (low hazard — minor agricultural/storage), II (standard buildings — most residential, commercial, industrial), III (substantial hazard — schools, jails, assembly >300 people), IV (essential facilities — hospitals, fire/police stations, emergency shelters). Higher Risk Categories receive higher design wind speeds for the same location.

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Design pressure in eight seconds.
With Florida Building Code overrides built in.

The only free wind load calculator that returns the legally enforceable wind speed for Miami-Dade, Broward, and Collier counties — not the ASCE map value your plan reviewer will reject.

FBC overrides built in Every coefficient cited 33,783 US ZIPs covered

Calculating wind loads since 2002, online since 2006.

Free Wind Load Calculator

ZIP Code 5-digit US ZIP

Risk Category ASCE 7-22 Table 1.5-1

Exposure Category ASCE 7-22 §26.7

Enclosure ASCE 7-22 §26.13

Mean Roof Height feet

Component Dimensions feet

Component Zone Fig 30.3-1 / 30.4-1

Your design pressure

Computed live as you change inputs. Uses the same ASCE 7-22 + Florida Building Code engine the paid version runs — every coefficient traceable to its source.

The pressure shown is for ONE wall component. Need a schedule across every opening on a project, with Excel export, PE-stampable PDFs, and MWFRS results? Try the full version free for 7 days →

Design Pressure — idle

Max positive (pressure)

—.—psf

Max negative (suction)

—.—psf

Enter a ZIP and your inputs — the result appears here live.

Coefficient	Value	Reference
Calculation pending — enter your inputs above.

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How it works

From ZIP to design pressure in four steps.

No marketing flow, no email gate. The same calculation engine engineers pay for, exposed for one component at a time so you can verify a number quickly.

Enter the project ZIP

The calculator looks up basic wind speed automatically and applies Florida Building Code overrides for HVHZ counties (Miami-Dade, Broward, Collier).

Pick Risk Category & Exposure

Risk Category I–IV per ASCE 7-22 Table 1.5-1. Exposure B/C/D per ASCE 7-22 §26.7.

Specify building & component

Enclosure (all 4 ASCE 7-22 types), mean roof height, wall component width × height, and Zone 4 (interior) or Zone 5 (corner).

Read the pressure

Governing positive and negative design pressures in psf. Expand "Show the math" to see every coefficient cited to its ASCE 7-22 section.

The differentiator

Florida Building Code wind speeds that supersede ASCE 7-22.

Florida Building Code R301.2(7) sets county-specific wind speeds that legally override the ASCE 7-22 basic wind speed map. Plan reviewers in Miami-Dade, Broward, and Collier counties will reject submissions designed to the ASCE map value. The calculator returns the FBC value automatically.

County	Risk Cat I	Risk Cat II	Risk Cat III	Risk Cat IV	Source
Miami-Dade (HVHZ)	165 mph	175 mph	186 mph	195 mph	FBC R301.2(7)
Broward (HVHZ)	156 mph	170 mph	180 mph	185 mph	FBC R301.2(7)
Collier	151 mph	170 mph	180 mph	190 mph	FBC R301.2(7)

Note: Additional Florida counties (including Monroe, Palm Beach, Lee, and Sarasota) are pending verification and addition. ZIPs in those counties currently return the ASCE 7-22 basic wind speed map value at the ZIP centroid.

Risk Categories

What Risk Category to choose.

Per ASCE 7-22 Table 1.5-1, Risk Category classifies buildings by the consequences of failure. Higher Risk Categories receive higher design wind speeds for the same location.

Risk Category I: Low hazard to human life in the event of failure. Minor agricultural and storage buildings.
Risk Category II: Standard buildings not in I, III, or IV. Most residential, commercial, and industrial buildings. (Default for most projects.)
Risk Category III: Substantial hazard to human life: schools with capacity > 250, jails, assembly buildings > 300 occupants, healthcare with surgery but not emergency.
Risk Category IV: Essential facilities: hospitals with emergency, fire and police stations, emergency operations centers, designated disaster shelters.

Methodology

How design pressure is calculated.

Per ASCE 7-22 Chapter 30, the design pressure for a wall component is:

p = q_h × [(GC_p) − (GC_pi)] (Eq. 30.3-1)

Where

q_h = 0.00256 × K_z × K_zt × K_d × K_e × V² (Eq. 26.10-1)

Coefficients

V — Basic wind speed (mph). From ASCE 7-22 Figure 26.5-1, or from Florida Building Code R301.2(7) where applicable.
K_z — Velocity pressure exposure coefficient. ASCE 7-22 Table 26.10-1, varies with height and Exposure Category.
K_zt — Topographic factor. ASCE 7-22 §26.8.2 (1.0 for non-topographic sites).
K_d — Wind directionality factor. ASCE 7-22 Table 26.6-1 (0.85 for components and cladding).
K_e — Ground elevation factor. ASCE 7-22 Table 26.9-1.
(GC_p) — External pressure coefficient. ASCE 7-22 Figure 30.3-1 (h ≤ 60 ft) or 30.4-1 (h > 60 ft), varies with zone and effective wind area.
(GC_pi) — Internal pressure coefficient. ASCE 7-22 Table 26.13-1, by enclosure classification.

Sources

Where the numbers come from.

Every value returned by this calculator traces to a published standard or code. Verified as of 2026.

ASCE/SEI 7-22 Minimum Design Loads and Associated Criteria for Buildings and Other Structures (2022 edition). American Society of Civil Engineers. Chapters 26 and 30.
Florida Building Code, 8th Edition (2023) Residential R301.2(7) jurisdictional wind speed amendments. Florida Department of Business and Professional Regulation.
International Building Code 2024 Adopts ASCE 7-22 by reference (Section 1609).
USPS ZIP Code Database 33,783 5-digit US ZIP codes with city, county, state, and centroid coordinates.
In-house Florida-licensed Professional Engineer Reviews jurisdictional override values against current FBC text.

Frequently asked

Common questions.

Is this wind load calculator really free? What's the catch?▾

Yes, fully free with no signup and no usage meter. The calculator returns the design pressure for one wall component. For multi-component schedules, Excel export, PE-stampable PDFs, MWFRS calculations, or all six roof shapes, you need our paid subscription. The free tool is genuinely free — it's a slice of the paid product, not a trap.

How do you handle Florida Building Code wind speeds that supersede ASCE 7-22?▾

When you enter a Miami-Dade, Broward, or Collier county ZIP, the calculator automatically returns the FBC-required wind speed instead of the ASCE 7-22 map value. The badge shows you both values and cites Florida Building Code R301.2(7). Most online calculators (including SkyCiv) return the ASCE map value only, which is below the legally required value for permit submission in HVHZ counties.

Which Florida counties have FBC wind speed overrides?▾

Currently Miami-Dade, Broward, and Collier counties. Other Florida counties return the ASCE 7-22 map value at the ZIP centroid. We are adding additional Florida counties (including Monroe, Palm Beach, Lee, and Sarasota) based on verified Florida Building Code references.

What ASCE 7 edition does this calculator use?▾

ASCE 7-22, the current edition adopted by the 2024 International Building Code. For Florida projects, the calculator also applies Florida Building Code 8th Edition (2023) jurisdictional overrides.

What is the difference between basic wind speed and design wind pressure?▾

Basic wind speed (V, in mph) is the 3-second gust speed at 33 ft above ground in Exposure C, mapped per ASCE 7-22 Figure 26.5-1. Design wind pressure (p, in psf) is what the basic wind speed produces on a specific component after accounting for height, topography, directionality, elevation, and external/internal pressure coefficients.

What is the wind speed in Miami, Florida?▾

Per Florida Building Code R301.2(7), Miami-Dade County requires 175 mph for Risk Category II (standard buildings), 165 mph for Risk Category I, 186 mph for Risk Category III, and 195 mph for Risk Category IV. These values supersede the ASCE 7-22 map values for any permit submission in Miami-Dade.

How is this different from SkyCiv's free wind load calculator?▾

Two differences. First, jurisdictional accuracy: SkyCiv returns ASCE 7-22 map values only and does not apply Florida Building Code overrides; our calculator applies FBC overrides for Miami-Dade, Broward, and Collier so the returned wind speed matches what your plan reviewer requires. Second, friction: SkyCiv limits free users to 3 solves per week and a single roof shape; our free calculator has no signup, no meter, and shows every coefficient with its ASCE section reference.

What is the edge strip dimension "a" minimum?▾

Per ASCE 7-22, edge strip dimension "a" = 10% of the least horizontal dimension or 40% of mean roof height, whichever is smaller, but not less than 4% of least horizontal or 3 ft. Florida projects must use 4 ft minimum per Florida Building Code Residential 8th Edition Figure R301.2(7).

Can I use this calculator output for a building permit submission?▾

The calculator returns mathematically correct ASCE 7-22 + FBC pressure values, but permit submissions typically require a sealed engineering report. For PE-stamped Florida wind load reports (single-family residential, max 3 stories), use our paid subscription or contact us for individual project services. Out-of-state PE stamps are not offered.

What does Risk Category mean?▾

Risk Category per ASCE 7-22 Table 1.5-1 classifies buildings by the consequences of failure: I (low hazard, minor agricultural/storage), II (standard buildings), III (substantial hazard, schools, jails, assembly > 300), IV (essential facilities, hospitals, fire/police, emergency shelters). Higher Risk Categories receive higher design wind speeds for the same location.