Foster Apps

Terms of Use and Sale

For the fosterapps.com web calculators and Foster Tools Pro. Last updated October 27, 2026.

Who we are

fosterapps.com is run by Foster Apps LLC ("we", "us"). Contact: support@fosterapps.com. Our iPhone and Android apps have their own terms on each app's page; this page covers the website.

The free calculators

The calculators give estimates from standard formulas and the inputs you enter. They are a planning aid, not engineering, code-compliance or professional advice. Check results against the codes, manufacturer data and design standards that apply to your job, and have qualified professionals review work where required. We aren't liable for decisions made from calculator results.

Foster Tools Pro

  • What you get: the Pro features of the tools in Foster Tools Pro on fosterapps.com, on any device where you sign in with the email you bought it with. Pro on the website is separate from in-app purchases in our mobile apps.
  • Price and billing: the price shown when you choose a plan (US dollars), plus any sales tax or VAT shown at checkout. Payments are processed by Stripe.
  • Automatic renewal: monthly and yearly subscriptions renew at the end of each period and are charged to your payment method until you cancel.
  • Lifetime: when offered, a one-time payment for Pro access with no renewals. "Lifetime" means for as long as we operate Foster Tools Pro, not the life of the buyer. It covers the Pro features of the tools in Foster Tools Pro when you buy, and the tools we add to Foster Tools Pro afterwards. We may also offer separately priced products outside Foster Tools Pro; if so, we'll say clearly before purchase that they aren't included. Limited-time lifetime prices end on the date shown with the offer.
  • Cancel anytime: use "Manage Pro" on any calculator page, or the link in your Stripe receipt. Pro stays on until the end of the period you've paid for.
  • Refunds: if Pro isn't working for you, email us within 7 days of a charge and we'll refund that charge, or within any longer period the law where you live requires.
  • Price changes: we'll email you before a price change takes effect on your subscription, and you can cancel before it does.

Acceptable use

Don't resell or share Pro access, scrape the calculators at scale, or interfere with the site. We may suspend access that breaks these terms.

Changes and availability

We improve the calculators over time and may change or retire features. If we discontinue Pro, we'll refund the unused part of any prepaid period.

Disclaimer

The site and Pro are provided "as is" without warranties of any kind. To the extent the law allows, our total liability for any claim is limited to the amount you paid us in the 12 months before it. Nothing here limits rights you have under consumer protection laws that can't be waived.