Simple pricing
Start free. Upgrade when you need more.
Free
$0
Forever free, no card needed
Open calculators →- ✓All basic calculators
- ✓DC, AC, Filter, Op-Amp formulas
- ✓Solve for any variable
- ✓Search & filter by topic
- ✓Mobile friendly
MOST POPULAR
Pro
$4.99/month
Or $29/year (save 50%)
- ✦Everything in Free
- ✦AI explain any formula (Claude-powered)
- ✦Bookmark favourite formulas
- ✦Calculation history
- ✦Download as PDF for exam revision
- ✦Pro-only calculators (MOSFET, PCB, Skin depth)
- ✦Priority support from the developer
Frequently asked
Can I cancel anytime?
Yes, cancel anytime from your account. You keep Pro access until the end of the billing period.
What payment methods are accepted?
All major credit and debit cards, Apple Pay, and Google Pay through Lemon Squeezy.
Is the free tier really free?
Yes, fully free forever. No credit card required. All basic calculators are always free.
How does the AI explanation work?
Pro users can tap "AI Explain" on any formula. Claude gives a plain-English explanation of what the formula means, when to use it, and why it works.