EstimatorSuite
Free construction calculators for contractors — no signup
Last year I watched a roofer friend punch a roof measurement into a paid online calculator that looked like it was built in 2005. Then he did it again for the next job. And the next.
That's when I started building what I wished existed: free construction calculators that don't suck.
## The pain was real
Estimators and tradespeople live on two things: speed and accuracy. A roof takeoff, a concrete pour, an HVAC load calc — every job needs math before the bid goes out.
Two things kill them:
- Slow bids lose jobs. Customers get three quotes and usually go with whoever answers first. HBR's 2011 lead-response study found you're roughly 7x more likely to qualify a lead in an hour than in 2 hours (qualify rate, not close rate) — contractors feel this every day.
- Takeoff misses eat profit. Miss the insulation, the sealant, the fasteners — each line item is hundreds to thousands of dollars. A few misses and the job's profit is gone.
So the tool had to be fast, free, and cover the stuff estimators actually measure.
## What I built
42 calculators total: 36 material calculators (concrete, roofing, drywall, flooring, excavation, fencing…) plus 6 industry-specific estimators for HVAC, plumbing, electrical and more.
Rules I set for myself:
1. No signup. Type numbers, get answers.
2. Real US pricing data baked in, verified against vendor sites and cost guides.
3. Every calculator works on a phone — job sites don't have desks.
## Then I open-sourced it
The calculation engine is MIT-licensed and published on npm as @estimatorsuite/calculators — pure functions, no UI. A dev can npm install and get a verified concrete mix calculator without rebuilding it. That part surprised me: open-sourcing a niche tool got the most attention of anything I'd shipped.
## Where it stands
- 42 free calculators, no signup, backed by US pricing data
- Software reviews for 9 estimating tools (tested with the same 1,500 sq ft HVAC scenario, not vendor blurbs)
- Everything free — the reviews carry transparent affiliate links
I'm still early. If you're in construction or know estimators, I'd love feedback on what's missing. Try it: https://estimatorsuite.com
Or tell me what calculator you wish existed — I'm adding them by hand anyway.
1 Comment
The fact that open-sourcing the calculation engine got more attention than the product itself is an interesting result. Curious what kind of response came from that audience.