Period Tools vs CalcFence

A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.

Period Tools compared with CalcFence
Detail	Period Tools	CalcFence
What it does	Free, accurate cycle and period predictor	Free fence calculators for posts, rails, pickets, panels, concrete and installed cost estimates
Stage	Startup	Not given
Founded	2026	Not given
Based in	Not given	US
Pricing model	Freemium	Free
Pricing	All calculators and guides are free. Period Tools Pro (optional): $4.99/month or $19.99/year.	Not given
Key features	Predicts next 6 periods Calculates ovulation day Identifies fertile window Private on-device tracking Cloud sync for Pro subscribers No signup required	Material quantity calculators for posts, rails, pickets and concrete Installed cost estimates by material type and US state Support for multiple fence styles including privacy, picket, chain link, vinyl and split-rail Gate calculations and multiple layout options Published formulas and calculation methodology Planning guides covering post spacing, depth and frost lines by state
What makes it different	No data collection or server storage Uses standard medical calculation methods Honest about limitations and accuracy No aggressive marketing tactics	All formulas are published and explained on every calculator page Accounts for regional cost differences using construction cost index Covers multiple fence materials and styles in one set of tools
Community votes	0	0
DR (Domain Rating by Ahrefs)	14 −1 (down) since last check	6 no change since last check
Trust Flow (Majestic)	20	4
Citation Flow (Majestic)	9	17
Referring domains (Majestic)	77	4

4 details filled in for both companies.