Hourglass didn’t start as a new idea. It started as one section of Forecast Planner, our web app for 12-month cash flow and net worth forecasting. Forecast Planner treats debt as one piece of a bigger picture, rolled into a single net worth projection alongside cash, investments, and property. That worked fine, but it meant the debt payoff math was buried a few clicks deep inside a much larger tool.
What we kept noticing was that the debt section was the part people actually wanted to play with. They’d nudge the extra payment number around and watch the payoff date move. So we pulled it out into its own app. Same math underneath, but with nothing else competing for attention.
Pulling it out raised another question. Forecast Planner needs an account because it’s a subscription product that has to remember your forecast across sessions and devices. A standalone debt calculator doesn’t need any of that. When we asked what a debt app actually requires from you, the answer turned out to be almost nothing: a balance, an interest rate, and a payment.
That’s what Hourglass became. It’s a forward-looking debt payoff calculator for iOS. You enter your debts, set your payments, and see when you’ll be done and how much interest you’ll pay getting there. Then you drag one slider, the extra monthly payment, and watch years fall off the timeline.
Your data never leaves the phone
Debt balances are some of the most sensitive numbers a person has, so we drew a hard line early on: no bank connections, ever. You type your balances in yourself. There’s no login to your bank, no Plaid-style OAuth flow, no transaction feed syncing in the background. Everything lives in a local SQLite database on your phone. No account to create, no cloud sync, no server anywhere that could leak your information. Our privacy policy is short because there isn’t much to disclose. We don’t collect analytics, we don’t run ads, and we couldn’t look at your data if we wanted to, because it never reaches us.
This wasn’t purely an ethics call, either. It made the product simpler. No login screens to build, no sync conflicts to untangle, no backend to keep running. The app opens straight into your numbers.
Show the future, not the past
Most finance apps are rearview mirrors. Here’s what you spent last month, here’s what you paid. That’s useful information, but it doesn’t change what you do next. What changes behavior is seeing that an extra $200 a month makes you debt free three years and seven months sooner, and saves you thousands of dollars in interest along the way.
Every screen in Hourglass is built around that question of what happens if. Payoff dates, month by month amortization, interest saved, scenarios compared side by side. The math runs instantly on the device while you drag.
Pay once and own it
Hourglass is free for 30 days with everything unlocked, which is long enough to see two full monthly payment cycles. After that, Hourglass Pro is a one-time purchase of $4.99. There’s no subscription, and there never will be.
A debt payoff app that charges you every month forever has a conflict of interest baked into its business model. We’d rather sell you a tool once, the way you’d buy a hammer.
What shipped
Hourglass is on the App Store now, with per-debt profiles, a scenario calculator, payoff timelines, and payment reminders. All of it runs locally and stays private. You can read more about the app or find it on the App Store.
And if you’re thinking about building an app with this shape, small and focused and honest about privacy, that’s the kind of work we do for clients.