Comparison
PreCal-IQ vs. STACK (STACK Construction Technologies)
STACK has built a strong mid-market position in cloud takeoff, and its recent AI features (auto-detection on drawings, GPT chat) reflect the broader industry shift toward AI-assisted estimating. PreCal-IQ shares the goal but starts from a different place — the spec book — and treats drawing parsing as one input among several rather than the central problem.
Bottom line
STACK is a widely-adopted cloud takeoff and estimating platform with growing AI features — auto-detect on doors, windows, rooms, and walls, plus a GPT-powered chat. PreCal-IQ takes the AI one layer deeper: it reads the CSI spec book alongside the drawings and cross-references both, so the takeoff includes scope that lives in the spec text rather than on the drawing.
Feature comparison
Side-by-side
| Feature | PreCal-IQ | STACK |
|---|---|---|
| AI extraction on drawings | Yes — vision AI parses drawings and schedules | Yes — auto-detect doors, windows, rooms, walls |
| CSI spec book parsing | Yes — every line item from every section | No — drawing-focused with GPT chat for plan Q&A |
| Hardware group / finish schedule resolution | Automatic from spec sections | Estimator looks up in spec manually |
| Spec ↔ plan cross-reference | Every line item tied to spec section + drawing location | Not the focus |
| Multi-trade takeoff from one upload | All 45 CSI categories in one pass | Per-project setup; trade by trade |
| Vendor pricing portal | Built-in | Not standard |
| Bid integration | Built-in bid builder + Excel export | Estimating module included |
| Starting price | $499 / mo (Starter plan) | $2,999 / user / yr (1 user); ~$2,199 / user / yr for 3+ |
In practice
How each holds up under real workflow
A team already on STACK that's happy with the drawing workflow
STACK's drawing workflow is solid and the auto-detect features genuinely speed up takeoff. If the spec book layer isn't doing meaningful work on your projects — small commercial fit-outs, residential, single-trade — STACK + its AI assist may be all you need. PreCal-IQ's value scales with spec complexity.
A GC bidding work where the spec book defines significant scope
Healthcare, education, government, and large commercial bids carry spec-defined scope that doesn't appear on the drawings — testing requirements, owner-furnished items, hardware groups, finish schedules, mock-ups. STACK doesn't read the spec book, so this scope stays the estimator's responsibility. PreCal-IQ extracts all of it automatically.
A mid-market firm comparing annual subscription economics
STACK's takeoff + estimate pricing is $2,999/user/year for one user, falling to about $2,199/user/year at three users — call it $6,500/year for a three-person estimating team. PreCal-IQ Professional is $1,499/month for three users, with unlimited takeoffs and the spec-reading layer included.
FAQ
Common questions
Does STACK's GPT chat read the spec book like PreCal-IQ does?
STACK's GPT chat lets you ask questions about your project plans — it's a conversational layer on top of the takeoff data, not a spec extraction engine. PreCal-IQ parses the entire CSI spec book end-to-end and writes every line item into the takeoff, which is a different category of work.
When is STACK the better choice?
When your work is concentrated in drawing-driven scope, you want a tight cloud-takeoff + estimating bundle, and your team is already familiar with the STACK workflow. STACK's estimating module is mature and the AI auto-detect features are real.
Can I run PreCal-IQ and STACK side by side?
In principle yes — they overlap on drawing parsing, so most teams pick one for the takeoff itself. If you're a STACK shop evaluating PreCal-IQ, the typical experiment is to take a real project that hit you with a spec change mid-bid and see what each tool catches.
How does PreCal-IQ's pricing compare to STACK?
STACK's takeoff + estimate is $2,999/user/year for one user, ~$2,199/user/year for three or more. PreCal-IQ Starter is $499/month for one user ($5,988/year), Professional is $1,499/month for three users ($17,988/year). STACK is cheaper per seat at low headcounts; PreCal-IQ's included spec reading + vendor portal + unlimited takeoffs change the equation as you scale.
See PreCal-IQ side-by-side with STACK
Bring your own spec set to a 30-minute demo. See the takeoff generated live on your project.