Rectangular Tank Volume calculator

Volume of rectangular tanks, totes, sumps and aquariums. Exact geometry, instant results, nothing leaves your browser.

FIG. 1 — TANK CROSS-SECTION · LIVE

SCALE AUTO · REV A

01 · Tank shape

02 · Dimensions

Dim. unit

Liquid

03 · Fill depth (dipstick)50%

Wetted depth—

Surface width—

Ullage—

Liquid volume at fill depth

—US gal

Total capacity—

Filled · liters—

Filled · ft³—

Percent full—

Liquid weight—

Remaining to full—

Exact segment geometry — see methodology. Dished-head propane math is documented there too.

Rectangular tanks — aquariums, sump pits, transfer tanks, IBC totes — are length × width × depth, but the unit conversions are where mistakes happen (231 cubic inches per US gallon trips everyone up at least once). Enter the three inside dimensions and read gallons, liters and cubic feet directly.

For aquariums, remember the rated size is the brim-full volume; subtract substrate and the air gap for real water volume — drop the fill slider an inch or two to model it.

How this is calculated

Total volume

V = L·W·H

Filled volume at liquid depth h

V(h) = L·W·h

Every slice is the same rectangle, so volume is exactly linear in depth. See the full derivation, a worked example and a fill-ratio table on the rectangular tank formula page.

FAQ

TVC-103/FAQ

How many gallons is a 48×24×30 inch tank?

About 149.6 gallons brim-full — enter the dimensions above to see it live, and lower the fill slider for the working volume.

Is an IBC tote really rectangular?

Close — the bottle has rounded corners, so real capacity is slightly below the rectangular model. Our IBC chart notes the difference.