Period Tools vs Disk Prices

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 Disk Prices
Detail	Period Tools	Disk Prices
What it does	Free, accurate cycle and period predictor	Compare HDD and SSD prices with full specifications and price per terabyte in the US
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	Customizable columns for specifications like RPM, CMR/SMR, IOPS, TBW, and warranty Price per TB and price per GB calculations for fair capacity comparison Full-parameter comparison table with 50+ specifications per drive
What makes it different	No data collection or server storage Uses standard medical calculation methods Honest about limitations and accuracy No aggressive marketing tactics	Includes 50+ specifications from manufacturer documentation, not just price and product name Critical fields like capacity, media type, and CMR/SMR recording type are manually verified for accuracy Community-maintained workspace where edits are reviewed and shared with all users
Community votes	0	0
DR (Domain Rating by Ahrefs)	15 no change since last check	27 no change since last check
Trust Flow (Majestic)	20	8
Citation Flow (Majestic)	9	28
Referring domains (Majestic)	77	116

4 details filled in for both companies.