Termite treatment sizing: trench gallons, bait stations, and slab pre-treat

Termite work is the part of a pest-control book where the numbers get big and the units stop agreeing with each other. A liquid barrier is measured in hundreds of gallons along a foundation. A bait job is measured in stations around the same foundation. A pre-construction pre-treat is measured across a slab footprint. A tent job is measured through the whole volume of the house. Six free Fieldwynn calculators cover that ground, and this page says what each one takes in, what it hands back, and which measurement you need in your hand before you open it.

The calculators here come from the team building Fieldwynn, pre-launch field-service software for small crews — the next-step link at the end of this page points to its early-access waitlist. Read it as a recommendation with a funnel behind it rather than a neutral verdict. The calculators stay free permanently, and the line drawn in the box below holds no matter whose software you run.

The six calculators at a glance

Read the table by the measurement you already have. The left column links straight to each tool; the other two columns are what it asks for and what it returns, so you can jump to the right one without opening three.

Why termite work prices per linear foot

This is the distinction that makes termite estimating different from almost everything else a pest-control company sells, and it is the reason two honest quotes for the same house can look nothing alike.

Perimeter methods are priced along the foundation. A liquid soil barrier and a ring of in-ground bait stations both follow the building’s outline, so the unit that scales with the work is the linear foot. Whole-structure methods are priced across the building. Tent fumigation and whole-house heat treat the entire structure at once, so the unit that scales is the square foot. Fixr’s US national cost guide, last updated in January 2025, prices those two families exactly that way: liquid treatment at $4.00–$14.50 per linear foot and baiting systems at $8.00–$12.00 per linear foot, against fumigation or heat at $1.00–$4.00 per square foot and micro or spot treatment at $6.00–$8.00 per square foot.

Those look like comparable numbers. They are not. Take a single-story 2,000-square-foot home with a roughly square footprint: its foundation perimeter is about 179 linear feet, because the perimeter of a square is four times the square root of its area. Run Fixr’s bands through that house and the liquid barrier lands somewhere around $716 to $2,596, the bait ring around $1,432 to $2,148 — and the tent or heat job around $2,000 to $8,000. Same house, same day, a spread that has nothing to do with severity and everything to do with which yardstick the method uses.

The conversion factor is the thing worth carrying in your head. On that house, one linear foot of foundation corresponds to about 11 square feet of floor area. So a per-square-foot rate and a per-linear-foot rate are separated by roughly an order of magnitude, not by a margin you can eyeball. Quote a per-foot number where a per-square-foot number belongs and you are not slightly off; you are wrong by a factor of ten.

It gets sharper on a two-story house. Add a floor and the square footage doubles while the foundation perimeter does not move at all — the building sits on the same outline. A perimeter method costs almost exactly what it cost before; a whole-structure method roughly doubles. That single fact explains most of the “why is this bid so much higher” conversations in termite sales, and it is worth saying out loud on an estimate rather than leaving the customer to guess.

Two cautions on those bands. The micro and spot rate is priced per square foot of the treated zone, not of the whole house, so multiplying it across a full footprint produces a nonsense number. And the same guide’s stated national average of $680, inside a $450–$2,000 typical range, does not reach the perimeter band on a 2,000-square-foot home at all — it falls below the $716 floor that the guide’s own cheapest per-linear-foot liquid rate produces for that house. Averages across a national dataset are pulled down by small and partial jobs, and they make a poor anchor for a full-perimeter quote.

The termite treatment cost estimator implements that split rather than papering over it: pick a method and it selects the correct basis for you, derives a perimeter from square footage if you never measured one, and returns a low–typical–high band you can overwrite with your own market rate. Monitoring on a bait plan is always shown as a separate per-year line and never folded into the upfront figure, which is what keeps the methods comparable.

Liquid barrier jobs: sizing the trench

A liquid soil treatment is a volume problem before it is anything else. The University of Kentucky’s entomology extension is blunt about the scale: “A typical treatment may involve hundreds of gallons of a liquid pesticide, known as a termiticide, injected into the ground along the foundation, beneath concrete slabs, and within foundation walls.” Hundreds of gallons is a material cost you cannot estimate by feel, and it is a truck-loading problem you would rather not discover on site.

The termite trench termiticide gallons calculator takes the linear feet you will trench and how deep the trench runs, and returns the finished gallons to mix, the concentrate and water kept separate, and roughly how many bottles that is. The reason it exists as its own tool rather than as a row in a generic coverage calculator is depth. A vertical barrier is a volume, not a line, so the calculator asks how deep the trench runs and multiplies accordingly — which is why a shallow trench and a full-footing trench along the same foundation return very different gallon figures. Depth is a first-class input and accepts fractional feet, and the dilution figure is an editable field you fill from your own product’s label rather than a constant the tool asserts.

If your question is the other direction — not “how many gallons does this job need” but “how far does the case I already own stretch” — the termiticide concentrate yield calculator starts from bottle size and dilution and returns finished gallons per bottle, the trench distance that covers, and the cases the job consumes. The two are the same arithmetic solved for different unknowns. Both sit alongside the broader pesticide dosing calculators if the same visit also carries general pest work.

New construction: the slab pre-treat

A pre-construction pre-treat is a square-foot job living inside a linear-foot trade, which is exactly why it needs its own tool. The slab pre-treatment coverage calculator takes the footprint of the compacted pad the concrete will cap — house pad plus attached garage, porch, or carport, summed as separate sections so nothing is left out — and returns the finished gallons for the horizontal barrier plus the concentrate and water draw.

The input that earns the tool its keep is fill type. Coverage over coarse or gravel fill is figured at a higher rate than over normal compacted fill, and on a large pad that difference runs into the hundreds of gallons. Most online guidance mentions the coarse-fill adjustment in prose and then quietly leaves it out of the arithmetic. This one puts the toggle in front of you, because under-buying is the failure mode that stops a pour.

Pre-treatment work also carries a paperwork tail in the US. The National Pest Management Association’s forms guidance sets out that new-construction subterranean termite prevention is documented on the HUD-NPMA-99A “Subterranean Termite Protection Builder’s Guarantee”, completed by the builder, and the HUD-NPMA-99B “New Construction Subterranean Termite Service Record”, which “must be completed by the pest control company”. Sizing the pad correctly and documenting it correctly are the same job seen from two ends; log the applied quantities on a pesticide application log as you go and the record writes itself.

Bait systems: two station calculators, and which one you want

Bait is a slower instrument than a barrier, and its economics follow from that. The Kentucky extension notes that with in-ground stations “it may take weeks or months for termites to find the belowground installations and months more to achieve control”, which is why bait is almost always sold as a monitored program rather than a one-visit fix — and why the cost estimator keeps its monitoring fee on a separate annual line.

Two Fieldwynn tools count stations, and the distinction between them is worth thirty seconds. The termite bait station quantity estimator is the termite-specific one: it takes a foundation perimeter (or a length and width, if you would rather not walk it), applies your spacing interval, and rounds the division up — because flooring the count would leave one gap wider than the maximum spacing, which is the one gap that matters. It adds an optional interior allowance and a high-risk extras count you set for moisture, known activity, or wood-to-soil contact, and it is framed around the fixed-count packs that in-ground kits actually ship in.

The bait station count and spacing calculator is the general-purpose sibling. It carries spacing defaults for mice, rats and termites, splits perimeter stations from interior stations as two independently rounded terms, and will roll up a station-only material cost if you give it a per-station price. Reach for it when one account covers rodents and termites, or when a commercial site needs interior coverage costed separately. Reach for the termite tool when the question is simply how many stations to order for a house.

Either way, the number that comes out is a starting count and an ordering aid, not a placement plan. Where a station actually goes is a judgment made on site against the product label and what you found on the inspection.

Before any of it: the WDO inspection

Every number above assumes somebody has already walked the structure and written down what they saw. In the US, that record has a standard shape. The NPMA-33 is the “Wood Destroying Insect (WDI) Inspection Report”, and the word insect is load-bearing: it covers termites, carpenter ants, carpenter bees and reinfesting wood-boring beetles in existing properties, and only those. Wood-decay fungi are not on it — the National Pest Management Association’s guidance routes them to a separate Wood Destroying Attachment to the NPMA-33. That is the practical distinction between wood-destroying insects and the wider wood-destroying organism scope, and it is worth knowing before you write a finding on the wrong page. The same guidance sets out that HUD requires the report when the inspection is customary to the area, mandated by the state or local jurisdiction, when there is evidence of active infestation, or at the lender’s discretion.

The WDO / termite inspection worksheet is a field-notes organizer laid out in that familiar section order — a findings grid where every organism row starts at “no visible evidence” so you mark only exceptions, a conditions-conducive checklist, an obstructions and inaccessible-areas field, a recommendations area, and a blank sketch box to print and draw on. Nothing is saved anywhere; you fill it in the browser and print or save a PDF.

It is emphatically not the official form. It borrows the neutral section order and nothing else — no certification language, no registration-number framing, no regulatory weight — and it should never be submitted in place of the real report in a real-estate or lending transaction, which needs the official form completed and signed by a licensed inspector. What it is good for is the walk itself: a consistent sheet means your notes transcribe cleanly afterwards and the same conducive conditions get checked on every job. If the visit is a broader pest survey rather than a WDO-specific one, the general pest inspection checklist worksheet covers the wider scope.

Turning the sizing into a price that holds

Quantities are only half of an estimate. Once the gallons or the station count are settled, feed them into the chemical cost per job calculator to get the material floor for the visit — the number your price has to clear before labor, drive time and warranty exposure are even counted.

Warranty exposure is the part termite operators underprice most often, because it is a cost that arrives later. The Kentucky extension is direct that retreatment coverage depends on the customer keeping an annual renewal in force, which means the guarantee is a real, recurring obligation on your side of the ledger too. That is the shape of a termite bond : an upfront treatment followed by renewals, with a promise to come back at no charge attached. Priced properly it is the most durable form of recurring billing in a pest book; priced off the treatment alone it is a liability you have already sold. The pest control pricing calculator puts one-time, quarterly and annual plan structures side by side so the renewal actually carries the callbacks.

For the whole-structure side, fumigation volume is a different calculation again — cubic feet rather than square feet or linear feet, since a tent job is sized by the volume it encloses. And the rest of the trade’s tooling, from route planning to invoicing, sits in the pest control tool cluster.

Where this hub stops

Termites, as the Kentucky extension puts it, cause billions of dollars of damage a year in the US — which is why the trade exists and why the arithmetic is worth getting right. This page maps that arithmetic: what to measure, which tool consumes it, and which of the two pricing yardsticks the answer belongs on. It stops where every calculator on it stops. Sizing a job, ordering material, and pricing a bond are ours to automate; deciding what to apply, at what rate, and how to apply it safely belongs to the label and to your license. If you run a termite or general pest business and want the inspections, recurring bonds and renewal billing behind these jobs held in one place, the next step below points at the software we are building for that — the calculators stay free either way.