Free tools
Free, private calculators.
The same plain, no-nonsense thinking behind our apps, in a set of small tools you can use right now. Everything runs in your browser. Nothing is saved, nothing is sent, no account needed.
Tech
Buy smarter and run your Apple gear with confidence.
iPhone Storage Picker How many GB you really need, based on how you use your phone. On-device apps keep your data on the phone instead of a server, and that needs room. We built this after watching people buy the wrong size twice.
Beta Readiness Check Should you install the iOS beta? An honest five-question call. Every app we ship gets tested against each iOS beta, so we learned the hard way which betas are safe on your daily phone.
Battery Health Check Replace the battery now, soon, or ride it out. Background features like alerts and Live Activities lean on the battery. Worth knowing where yours stands before you blame an app.
Apple Intelligence Checker See if your device supports it and what runs on-device. We build apps like VeraCast and DayCast that run AI locally on your device, never on a server. Check whether your iPhone supports it here. See the app →
Privacy
Everything here runs in your browser, we could not see your data if we wanted to.
Passphrase Generator Strong, memorable passphrases plus a password strength checker. Same rule as our apps: your data should not have to leave your device to be useful. This one never sends a thing.
Photo Metadata Viewer See the hidden GPS and device data inside your photos. Renewl and Solecito read images entirely on-device with Apple's Vision framework. This shows you what is hiding in a photo before you share it. See the app →
iPhone Privacy Checkup A 10 minute settings audit with a score. The settings audit we run on our own phones. It is the same standard we hold the apps to, no analytics SDKs, no ad SDKs, no data sold. See the app →
Investing
Calm, long-term money math for buy and hold investors.
Dividend Snowball Watch reinvested dividends compound over 5 to 40 years. The math behind Holdwise, our dividend tracker. See the snowball here, then track your real one in the app. See the app →
Dividend FI Number How big a portfolio you need for dividends to cover your bills. Holdwise exists to answer this question with your actual holdings. This gives you the number in 30 seconds. See the app →
Coast FIRE Find out if you can stop contributing and still retire on time. DayCast tracks net worth privately on your device. This tool is the milestone that number is walking toward. See the app →
Asset Location Helper Which account should hold each fund, taxable, Roth, IRA, 401(k), HSA. A question our own investing apps kept raising, so we wrote the answer down.
Rebalance Calculator See your drift from target and the trades to fix it. Calm, once-a-year portfolio maintenance, the same buy-and-hold approach Holdwise is built around. See the app →
Expense Ratio Cost What a fund fee really costs over decades of compounding. Fees are the one investing variable you fully control. Worth seeing what a 0.5% difference really costs.
Subscriptions
See what those recurring charges really cost.
Subscription Cost Total your subscriptions by month, year, and decade. Renewl scans your receipts and warns you before a renewal hits. This is the total you are trying to bring down. See the app →
Work and pay
Plain-language pay math. General information, not legal advice.
Paycheck and Overtime Gross pay with overtime at time and a half over 40 hours. The calculator that turned into Plantilla, our workers' rights and pay companion, now in ten languages. See the app →
PTO Accrual Project your paid time off balance across the year. Written by an HR generalist who answers this question weekly. Plantilla does it with your real schedule. See the app →
Is Overtime Owed? A quick exempt vs non-exempt check under federal rules. The exempt vs non-exempt question behind Plantilla. General information, not legal advice. See the app →
Health
Everyday numbers explained plainly. Not medical advice.
Caffeine Calculator How much caffeine is still in you at bedtime. Steady helps shift workers sleep on a schedule nobody designed for them. Caffeine timing is half that battle. See the app →
Sleep Cycle Calculator Best bedtimes and wake times around 90 minute cycles. Steady plans naps and sleep windows around real shift patterns. This is the simple version of the same math. See the app →
Water Intake A sensible daily target without the hydration hype. VitalCast reads your Apple Health data on-device and explains it plainly. Same idea, one number at a time. See the app →
Heart Rate Zones Your five training zones from age and resting heart rate. VitalCast turns your Apple Health numbers into a briefing you can act on. Zones are a good place to start. See the app →
Pets
For the dogs and cats who run our households.
Pet Age Calculator Your dog or cat's age in honest human years. VitalLedger keeps every vaccine, vet visit, and weight for every pet in the house. Age is where most of those decisions start. See the app →
Dog Food Portions Cups per day from weight, life stage, and your food's calories. Built for Sophie and Luna first. VitalLedger tracks the weight this portion is meant to hold steady. See the app →
Can My Dog Eat That? A fast lookup of safe, risky, and toxic foods for dogs and cats. The lookup we wanted at 9pm on a Sunday. VitalLedger keeps the vet records for the times it goes wrong. See the app →
Fun
Because not every calculator has to be responsible.
Movie Marathon Planner Harry Potter, the MCU, Star Wars, Middle-earth. Total runtime and finish time. No app tie-in, we just wanted to know if the whole MCU fits in a long weekend.
Focus Timer A simple Pomodoro timer for focused work and breaks. Kynd is our focus app for ADHD brains, no streaks and no shame. This is the timer, stripped down. See the app →