Terrazzo Floor Calculator
Aggregate, binder, and divider strip for terrazzo installation.
About this calculator
This calculator splits a poured-in-place terrazzo job into three independent material streams that don't share the same inputs. Aggregate and binder quantities come from floor area, thickness, and the aggregate ratio together — raising the aggregate ratio (the percentage of marble or glass chips in the mix) increases aggregate weight but decreases binder volume by the exact same trade, since the two are defined as complementary shares of one fixed mix volume. Divider strip footage, by contrast, comes entirely from room length, room width, and divider spacing — it never changes when you adjust area, thickness, or the aggregate ratio, because the grid of zinc or brass strips is laid out from room dimensions, not mix chemistry.
Sealer gallons is the narrowest case: it depends on floor area alone (at a fixed 350 sq ft per gallon, two coats), completely unaffected by thickness, aggregate ratio, room dimensions, or divider spacing. Because divider spacing interacts with room length and width through floor and rounding, small spacing changes can occasionally leave the strip total unchanged — always check the number against a sketched grid layout before ordering strip stock.
Inputs
Results
Aggregate needed
1,458 lbs
≈ 8 adults
Binder (epoxy/cement)
47 gal
≈ 9 buckets
How to Use This Calculator
- Enter the total floor area (drives aggregate, binder, and sealer) and room length/width (drives divider strip footage only).
- Set the terrazzo layer thickness in inches (1/4 to 3/8 inch for epoxy, 1/2 to 5/8 inch for cementitious) — it affects aggregate and binder, not divider strips or sealer.
- Enter the divider strip grid spacing in feet; it only changes Divider strips, not any material quantity.
- Set the aggregate-to-binder ratio — raising it adds aggregate weight and removes binder gallons, an exact trade in mix volume, but not a matched trade once converted to pounds and gallons.
- Review the mix volume, aggregate and binder quantities, divider strip linear footage, and sealer gallons separately — each responds to a different subset of inputs.
How the result changes with Floor area
| Floor area | Aggregate needed | Binder (epoxy/cement) |
|---|---|---|
| 250 | 729 lbs | 24 gal |
| 375 | 1,094 lbs | 36 gal |
| 750 | 2,188 lbs | 71 gal |
| 1,250 | 3,646 lbs | 117 gal |
What each input means
- Floor area
- Total area to receive terrazzo.
- Room length
- Length of the room (for divider strip grid).
- Room width
- Width of the room (for divider strip grid).
- Terrazzo thickness
- Depth of terrazzo layer. Epoxy: 1/4"-3/8", cementitious: 1/2"-5/8".
- Divider spacing
- Grid spacing between divider strips (typically 3-6 ft).
- Aggregate ratio
- Percentage of aggregate in the mix (typically 70%).
What each result means
- Aggregate needed
- Weight of marble, glass, or stone aggregate chips.
- Aggregate (tons)
- Aggregate weight in US tons.
- Binder (epoxy/cement)
- Gallons of epoxy or cementitious binder.
- Divider strips
- Total linear feet of zinc or brass divider strips.
- Sealer
- Gallons of terrazzo sealer (2 coats at 350 sq ft/gal).
- Total mix volume
- Total volume of terrazzo material.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersFloor area = 500, Room length = 25, Room width = 20, Terrazzo thickness = 0.5 = 6 input(s) provided
- Calculate Aggregate neededAggregate needed1458 = 1458
- Calculate BinderBinder47 = 47
- Calculate AggregateAggregate0.73 = 0.73
- Calculate Divider stripsDivider strips290 = 290
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
If I increase the aggregate ratio, does that add material or just rebalance the mix?
It rebalances a fixed mix volume, not add material. Total volume is set by floor area and thickness only; the aggregate ratio then splits that fixed volume between aggregate and binder — in volume terms, the trade is exact: aggregate volume rises by precisely as much as binder volume falls. But Aggregate needed is reported in pounds and Binder in gallons, and those units convert from volume at different rates, so the two outputs don't move by matching, opposite amounts. At the default area and thickness, raising the ratio from 70% to 75% raises Aggregate needed by about 105 lb while lowering Binder gallons by only about 8 gal — a real trade, just not a 1:1 one once you look past the underlying volume.
Does changing the floor area or thickness affect how many divider strips I need?
No. Divider strip footage comes entirely from room length, room width, and divider spacing — the grid layout of zinc or brass strips is a geometric calculation independent of how thick the terrazzo pour is or what percentage of the mix is aggregate.
What determines the Sealer gallons figure?
Sealer gallons depends only on floor area, using an assumed rate of two coats at roughly 350 square feet per gallon per coat. Thickness, aggregate ratio, room dimensions, and divider spacing never change this number — a thin epoxy pour and a thick cementitious pour of the same area need the same sealer.
Why might increasing divider spacing slightly not change the strip total?
Divider strip counts are computed by dividing room length or width by the spacing and rounding down to a whole number of grid lines. A small spacing change can land in the same rounded-down bracket as the previous value, leaving the linear footage unchanged even though the spacing input moved — always verify against a sketched layout before ordering strip stock.
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