PaceCalc is now an iPhone app. The same 20 calculators that have lived on this site for the last two years — pace, race predictor, VDOT, training paces, intervals, BQ, age grading, heat and altitude, triathlon, swim, nutrition, the lot — are now native on iOS. Free. No signup. No ads. No tracking. Get it on the App Store.

That’s the whole headline. The rest of this post is for runners deciding whether they want it on their phone.

Why an app at all

The web version is fast, prerendered, and offline-capable for the calculators you’ve already loaded. We could have stopped there. But three things kept coming up in user mail:

Race morning. You’re in a parking lot with bad reception, trying to load a pace calculator. The web works, mostly — but “mostly” is not what you want with five minutes until corral close.
Lock-screen access. Runners wanted the calculator one tap from the home screen, not three taps inside a browser.
Share cards. People kept screenshotting the web results to post to Instagram and group chats. The screenshots looked rough. We could do better.

A native iPhone app fixes all three: zero-latency open, home-screen icon, and proper share-card export. That’s it. That’s the case.

What’s in v1

Every web calculator ships native, with one-to-one parity. The math is the same — src/lib/ on the website and the calculation layer in the app are derived from the same reference implementation, with shared test cases. Your pace per kilometer in the pace calculator on web is the pace per kilometer on the app, to the second.

The 20 calculators are grouped the same way as the homepage:

Pace, time, distance. Pace calculator, pace converter, treadmill converter, run/walk calculator.
Training. Training paces, VDOT, intervals, banger workouts, heart-rate zones.
Racing. Race predictor, Boston qualifier, age grading, race comparison, marathon nutrition, heat and altitude, weight impact.
Triathlon. Triathlon pace, swim pace.
Course-specific. Pace plans for the world marathon majors — NYC, Boston, Chicago, London, Tokyo, Berlin — built on real GPX elevation, grade-adjusted segment by segment.

Your VDOT score, units (metric or imperial), and last-used source race carry across calculators inside the app, exactly the same as on the site. Set your 5K time in the VDOT calculator, and every downstream tool — training paces, intervals, nutrition — reflects it without you re-entering anything.

This is the only meaningful feature in the app that doesn’t exist on the web. Open any calculator, fill in your numbers, tap Share. You get a Story-format card (1080×1920) in one of three layouts:

Broadside. One huge hero numeral. Your goal time, your pace, your finish prediction. Heavy serif display type, hi-vis lime punctuation, sitewide grain. The card a club would screen-print on a flag.
Terminal. Data-dense. Splits per kilometer or mile, training zones, course grade-adjusted segments. The card a stat-head would print and tape to their wristband.
Minimal. Split ink/paper. Big numeral, single line of context. The card that fits anywhere on a feed.

The cards are designed to be posted — to Instagram, to your group chat, to your training partner, to print and tape to your fridge. They’re high-contrast, properly typeset, and they read at thumbnail size. They include only what you put on them; there’s no analytics call back to us, no QR code phone-home, no embedded ad. Just the math, rendered well.

If you don’t post your training to anything, you can ignore this feature entirely. Most of the app is still free running calculators with no friction.

What’s not in the app

The thing we want to be loud about: there are no accounts, no email gate, no ads, no in-app analytics, no tracking. The app does not phone home. Your inputs live on your device. The share cards you generate include only the data you typed in.

There is also no cloud sync — at least, not yet. If you set a VDOT score in the app, it lives in the app. If you set it on the web, it lives in the browser. The two don’t sync. We’ve debated whether to add iCloud sync; we will only do it if we can do it without an account system. If we ever can’t, we won’t.

There is no Apple Watch companion in v1. Several users have asked. It’s on the list.

App vs web — when to use which

Pre-race week, sitting at your laptop: the web. Bigger screen, easier to copy splits into your training log or a spreadsheet.
Morning of the race, in a parking lot: the app. Faster open, no flaky reception dependency, share card ready to post when you cross the line.
Building a training week: either. The data model is identical.
Showing a friend a workout while you’re out for coffee: the app. One tap from the home screen.
Embedding a pace calculator in your own running blog: the web. We ship an embed for free.

There is no premium tier on either. Everything in the web version is in the app and vice versa, with the share cards as the only iOS-exclusive feature.

How we make money

We don’t, mostly. Optional in-app tips through Buy Me a Bagel are the entire revenue model. There are no ads, no subscriptions, no premium calculators, no upsell. If you find PaceCalc useful and want to throw us a bagel, that’s the only commerce in the app. If you don’t, you get everything regardless.

This isn’t a marketing flourish. It’s a constraint that decides design questions for us. Every feature has to justify itself without revenue. Features that would require an account system, server infrastructure, or per-user costs are off the table unless we can find a way to ship them locally. That’s why your VDOT lives in localStorage on the web and in the app sandbox on iOS, not in a database somewhere.

What’s next

We’re going to keep the roadmap honest:

More course-specific marathon pages. Two are already in the app from launch (Marine Corps and Melbourne, with real GPX). LA, Paris, Amsterdam, Philadelphia, Valencia, and Dublin are in with approximate profiles; we’re collecting real GPX data to upgrade them. Race directors: if you want your race in, email us.
Workout library expansion. Banger workouts is the start of a proper named-workout catalog. We want every Daniels, Hudson, Pfitz, and Hanson workout in there with VDOT-aware paces.
Apple Watch. Probably this year. Probably with no cloud sync and no companion-required setup. We’ll see.
Android. Honestly, not soon. The team is two people. iOS first; Android when we’ve got the bandwidth.

We’ll keep shipping web updates in parallel. The site is not getting deprecated. Anything we add to the app that makes sense on the web will land on the web too.

How to get it

The app is free on the US App Store. Download here. If you’ve been using the web version, all your calculators are there, exactly as you remember them, plus the share cards. If you’re new to PaceCalc, start with the pace calculator and the race predictor; those two cover 80% of what most runners need.

If you spot a bug, want to request a calculator, or want a marathon course added: pacecalc@suur.io. We read every email.

Run fast. Math later.

PaceCalc for iPhone is here.