Barometer & Altimeter vs Model Scale Calculator

Know your elevation. Follow pressure changes. Keep a useful record of your hikes, climbs, stairs and everyday observations—with clear readings on iPhone and iPad, plus Apple Watch, widgets and Live Activities on supported devices. • Current altitude above sea level, with relative gain and net change kept separate. Check the reading source and freshness; authorized GPS can provide a fallback where available. • Start, pause, resume and save a recording. Authorized background recording keeps a session going while you use another app or lock your phone. • Find, rename and favorite saved recordings, add notes, compare charts and share data as CSV. • Check your wrist, widgets or Live Activity. Use Siri and Shortcuts to read, record or open saved sessions; interactive controls are available on supported OS versions. • Keep familiar metric/imperial units, Set Zero and pressure-reference calibration. Choose automatic weather, manual reference or a nearby US weather station where available. Readings depend on device hardware, permissions, source availability and conditions. Widgets and complications refresh on the system's schedule, not continuously. Watch recording controls need a reachable iPhone; phone-free Watch recording is not included. Saved history and supported local readings work offline; weather and station updates need a connection. HowHigh is for observation, not certified navigation or safety-critical guidance.

A scale converter for people who build models. Pick a scale — HO, N, O, 1:35 armour, 28mm heroic, 1/4" = 1' — type a dimension, and read the answer as you type. Free, offline, no account, no ads. THREE ANSWERS, ONE SCREEN • Real → model — how big is a 40-foot boxcar in HO? • Model → real — this part measures 92 mm; what is that full size? • What scale is this? — give a real length and the model length it has to come out at, and get the ratio. COMPARE ACROSS SCALES A second view takes one measurement and shows it in every scale in a hobby group at once — model railway gauges, military armour, aircraft, tabletop miniatures — with a proportional bar per row so you can judge the sizes by eye instead of reading numbers. UNITS HOBBYISTS ACTUALLY TYPE It parses what you would write on a workbench note: 250mm, 2.5 cm, 5' 6", 5ft 6in, 1 1/2", 3/4", 1-1/2". Feet-and-inches and fractional inches are first-class output formats, not an afterthought — fractions come back as fractions, rounded to the precision you choose. SCALES INCLUDED • Model railways — Z, N, TT, HO, OO, S, O, G and more • Military and armour — 1:16, 1:35, 1:48, 1:72 • Aircraft — 1:32, 1:48, 1:72, 1:144 • Cars — 1:18, 1:24, 1:43, 1:64 • Tabletop and wargaming — 15mm, 28mm heroic, 32mm, 54mm • Architecture — imperial drawing scales like 1/4" = 1' and metric 1:50, 1:100 • Any custom ratio you type WORKS COMPLETELY OFFLINE No account, no sign-in, no sync, no paywall and no advertising. Every calculation happens on your device, and nothing you type is ever sent anywhere. The only thing the app ever sends is anonymous usage data — which scales and modes get used — and you can switch that off in Settings. For model railroaders, scale modellers, miniature painters, RC builders, dollhouse makers, architects and anyone who has ever stood in a hobby shop doing long division on their phone.