Period Tools vs BRI Calculator

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 BRI Calculator
Detail	Period Tools	BRI Calculator
What it does	Free, accurate cycle and period predictor	Calculate your Body Roundness Index instantly. Free, Fast, and Revealing.
Stage	Startup	Not given
Founded	2026	Not given
Based in	Not given	Not given
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	Free calculation with no registration required Optional gender and age personalization Average BRI data by age and gender Interpretation guidance for results Detailed waist measurement instructions Comparison with BMI Health risk assessment based on BRI ranges
What makes it different	No data collection or server storage Uses standard medical calculation methods Honest about limitations and accuracy No aggressive marketing tactics	Uses waist circumference for more accurate body composition assessment than BMI Better at predicting cardiovascular health risks More sensitive to changes in body shape and fat distribution Provides accurate results for people with high muscle mass
Community votes	0	0
DR (Domain Rating by Ahrefs)	15 no change since last check	25 no change since last check
Trust Flow (Majestic)	20	7
Citation Flow (Majestic)	9	18
Referring domains (Majestic)	77	55

4 details filled in for both companies.