Holdover Calculator2.2.1 - App Store

Holdover Calculator is a pre-departure decision tool for pilots facing winter operations. It returns the applicable anti-icing holdover or allowance time from FAA or Transport Canada published guidance, based on the actual weather, the de/anti-icing fluid applied, and your aircraft configuration.

DESIGNED FOR iOS 26

Built for iOS 26 and its Liquid Glass interface. The pilot answers a sequence of focused questions; the app shows the matching table cell, the published range, and a continuously interpolated estimate within that range.

KEY FEATURES

. Holdover and allowance times from the current FAA Holdover Time Guidelines and Transport Canada HOT Guidelines.

. Live weather autofill via the NOAA Aviation Weather Center - closest METAR or any ICAO you search.

. Manual entry always available when stations are out of range or you want to model conditions ahead.

. All four fluid types (Type I through Type IV) with both generic-table and specific-brand selections.

. Active Frost allowance and Ice Pellet allowance with a 90-minute takeoff-window tracker.

. Chart Notes surfaced inline, with active conditions (cold-soaked wing, OAT thresholds, etc.) flagged so you see only the notes that matter right now.

. App Estimated time - a continuous interpolation across OAT and precipitation intensity, shown alongside the FAA Recommended low end of every published range.

. Countdown timer with Live Activity on the Lock Screen. Minutes and seconds below an hour; hours and minutes above. The wall-clock "Ends at" reference is always shown to the second.

. Apple Watch companion for the crew member running the timer.

. Cockpit Sync - share one running timer across the flight deck. Link two to four pilots' devices over a direct local Wi-Fi/Bluetooth connection; the captain approves every change, and the link re-establishes itself if a device drops out of range. No account, no internet, no server.

. Readable on the ramp. Tap any advisory note - or any setting's description - to enlarge it in a comfortable card sized for reading-distance glasses.

. Support & Feedback in one tap. Reach the developer from the menu - write a note and attach a screenshot; your report includes a summary of what you changed this session so issues get resolved faster. No account required.

. FAA or Transport Canada as the global default, with per-calculation overrides.

. Local or Zulu time display; 12- or 24-hour clock.

PRE-DEPARTURE DECISION ONLY

This app is an advisor. The pilot in command remains solely responsible for verifying that the selected time is appropriate for the actual conditions, fluid, and aircraft at the moment of departure. Always cross-reference the current published holdover tables.

DATA SOURCES

. FAA Holdover Time Guidelines (current revision)
. Transport Canada Holdover Time Guidelines (current revision)
. NOAA Aviation Weather Center (aviationweather.gov) for live METAR observations

SUBSCRIPTION

Holdover Calculator is an auto-renewable annual subscription, with a free trial for new subscribers. Pricing is shown in the app before you subscribe.

. Payment is charged to your Apple ID at confirmation of purchase.
. The subscription renews automatically unless cancelled at least 24 hours before the end of the current period.
. Your account is charged for renewal within 24 hours before the period ends.
. Manage or cancel anytime in your Apple ID account settings.
. Any unused portion of a free trial is forfeited when you purchase a subscription.

PRIVACY

Location is requested only to identify the nearest weather station; your coordinates are sent solely to NOAA to run that query and are never stored or shared with us. No ads, no analytics, no tracking.

Privacy Policy: https://kilolimallc.github.io/legal/holdover-calculator/privacy.html
Terms of Use (EULA): https://kilolimallc.github.io/legal/holdover-calculator/terms.html
Disclaimer: https://kilolimallc.github.io/legal/holdover-calculator/disclaimer.html

Version History This update fixes one thing, and it matters.

• The disclaimer screen. On some devices the "Agree" button could stay greyed out even after you had scrolled down and read every word — leaving no way into the app at all. The button now becomes available as soon as you reach the bottom of the text.

If you opened the app and could not get past the disclaimer, this build clears it. Nothing else has changed: the same Winter 2026–2027 FAA and Transport Canada tables, the same fluids, the same results.

Our thanks to the pilot who took the time to write in about this. A screen that won't let you in is also a screen you can't report a problem from, so that email is the only reason we found it. If something in the app ever looks wrong, please tell us.

Fly safe. 2.2.1 Sep 28 • Winter 2026–2027 tables. Every holdover and allowance time now comes from the FAA and Transport Canada guidelines issued 11 August 2026. Many times are shorter than last season's and none are longer, so it's worth updating before your next departure.

• New and withdrawn fluids. Added: LNT Solutions P250 and P450, MAX TECH MTL 4-EG and MTL 4-PG, MKS DevO COREICEPHOB Type I EG, Turbotect DF I, MAX TECH MTL EG-1 and MTL PG-1. AVIAFlight EG and six other fluids have been withdrawn by the publishers. If a fluid you had picked is no longer listed, the app tells you rather than quietly dropping it.

• The note that applies to your reading. Chart notes are now shown for the exact cell your answers land on, not just the column — including the rule that no holdover time exists below −10 °C for freezing drizzle and light freezing rain, which the guidelines print on individual cells.

• Type III speed category: "Not sure". The guidelines say to apply low speed test values when you can't establish which ramp test applies to your aircraft. You can now say so directly instead of guessing. Low speed publishes the same times where they overlap — what it changes is the coldest temperature the fluid can be used at.

• Snowfall intensity is shown even when it's the reason there's no time. If prevailing visibility means the intensity reads heavy, the result now says so plainly.

Plus accuracy and clarity work throughout. Fly safe. 2.2 Aug 30 • In-app notices. Holdover Calculator can now show the occasional important notice — app updates and time-critical information — right in the app, as a card you can dismiss. They're pulled from a public file: no account, no tracking. Revisit past notices anytime from the new Messages item in the ••• menu, and turn them off in Settings. Critical safety notices always show.

• Support & Feedback, redesigned. Reaching us now has its own menu item — write a note, attach a screenshot or two, and your report automatically includes a summary of what you changed this session, so we can help faster. Sends by email or the share sheet; no account required.

Plus reliability and clarity improvements throughout. Fly safe. 2.1.2 Jul 22 Version 2.1.1

• In-app notices. Holdover Calculator can now show the occasional important notice — app updates and time-critical information — right in the app, as a card you can dismiss. They're pulled from a public file: no account, no tracking. Revisit past notices anytime from the new Messages item in the ••• menu, and turn them off in Settings. Critical safety notices always show.

Plus reliability and clarity improvements throughout. Fly safe.

PRIOR
Version 2.1

• Organization deployment for flight departments. Holdover Calculator can now be licensed across a managed fleet through Apple Business Manager and MDM — no per-device Apple Account or App Store sign-in required. Contact us to set it up.

• Read it at a glance. Tap any orange advisory note — or any setting's description — to enlarge it in a comfortable card sized for reading-distance glasses. Drag down or tap Done to dismiss.

• Cockpit Sync now correctly identifies Mac devices in the nearby-pilots list (they previously appeared as "iPad").

• Settings and Help no longer close on an accidental swipe — tap Done to dismiss, so a long scroll isn't lost.

• Includes the 2.0.1 fix for restoring an active subscription on a new device. v2.1.1 Jun 26 Version 2.1

• Organization deployment for flight departments. Holdover Calculator can now be licensed across a managed fleet through Apple Business Manager and MDM — no per-device Apple Account or App Store sign-in required. Contact us to set it up.

• Read it at a glance. Tap any orange advisory note — or any setting's description — to enlarge it in a comfortable card sized for reading-distance glasses. Drag down or tap Done to dismiss.

• Cockpit Sync now correctly identifies Mac devices in the nearby-pilots list (they previously appeared as "iPad").

• Settings and Help no longer close on an accidental swipe — tap Done to dismiss, so a long scroll isn't lost.

• Includes the 2.0.1 fix for restoring an active subscription on a new device.

Plus reliability and clarity improvements throughout. Fly safe. 2.1 Jun 18 This update fixes a subscription-restore issue and includes everything from the Version 2 redesign.

FIXED IN 2.0.1

• Restore Purchases could fail to restore an active subscription on a new device — you'd enter your Apple ID and land back on the paywall with no feedback. Tapping Restore now shows what's happening and reliably restores an existing subscription.

VERSION 2 — A complete redesign for iOS 26.

This release rebuilds Holdover Calculator from scratch around Apple's new Liquid Glass design language. Every screen, every input, every result is new — but the data and the regulatory guidance behind it remain the same.

WHAT'S NEW

• Brand-new interview flow. Weather, Fluid, and Aircraft are now three clearly-separated sections with floating section pills you can tap to jump between. Pre-set your defaults in Settings and you'll answer only the questions that actually need answering for a given operation.

• Live weather autofill. Tap "Use Nearby" and the app pulls the closest METAR from the NOAA Aviation Weather Center. Search any ICAO directly, or enter the conditions manually — the app guides you to whichever source is appropriate for the conditions.

• Chart Notes, surfaced. A new Chart Notes panel shows every published note for the table you're using. Notes whose conditions are currently active (cold-soaked wings, ice-pellet limits, OAT thresholds, etc.) are highlighted so you see what matters first.

• App Estimated and FAA Recommended, side by side. Every range now shows both the FAA Recommended low end and a continuously-interpolated App Estimated time within the range — pick whichever fits the operation.

• Lock Screen Live Activity. The countdown timer now runs as a Live Activity. Glance at your Lock Screen for the remaining time and exact wall-clock end. Above an hour the timer reads in hours and minutes; below an hour, minutes and seconds.

• Ice Pellet allowance and the 90-minute takeoff window. Allowance lookups for ice pellets and freezing precipitation are first-class — the app tracks the 90-minute takeoff window after precipitation stops and shows whether takeoff is still permitted.

• Active Frost handling. Between roughly −5 °C and +10 °C the app prompts for active frost and switches to the Active Frost allowance when applicable.

• Apple Watch companion. Run the timer from your wrist.

• Cockpit Sync. Share one running holdover timer with up to four pilots in the same cockpit over a direct, local connection — no account, no internet. The captain approves every change, and the link re-establishes itself automatically if a device locks or briefly drops out of range.

• Time display options. Local or Zulu, 12- or 24-hour clock — set once in Settings.

• Send Feedback / Get Help from the toolbar Menu now prefills the support email with your app version, iOS version, and device model — no more typing those out.

For pilots upgrading from version 1: your subscription carries over. The data tables and regulatory guidance are unchanged. The interface is what's different — and we think you'll find it considerably faster from question to answer. 2.0.1 Jun 16 VERSION 2 — A complete redesign for iOS 26.

This release rebuilds Holdover Calculator from scratch around Apple's new Liquid Glass design language. Every screen, every input, every result is new — but the data and the regulatory guidance behind it remain the same.

WHAT'S NEW

• Brand-new interview flow. Weather, Fluid, and Aircraft are now three clearly-separated sections with floating section pills you can tap to jump between. Pre-set your defaults in Settings and you'll answer only the questions that actually need answering for a given operation.

• Live weather autofill. Tap "Use Nearby" and the app pulls the closest METAR from the NOAA Aviation Weather Center. Search any ICAO directly, or enter the conditions manually — the app guides you to whichever source is appropriate for the conditions.

• Chart Notes, surfaced. A new Chart Notes panel shows every published note for the table you're using. Notes whose conditions are currently active (cold-soaked wings, ice-pellet limits, OAT thresholds, etc.) are highlighted so you see what matters first.

• App Estimated and FAA Recommended, side by side. Every range now shows both the FAA Recommended low end and a continuously-interpolated App Estimated time within the range — pick whichever fits the operation.

• Lock Screen Live Activity. The countdown timer now runs as a Live Activity. Glance at your Lock Screen for the remaining time and exact wall-clock end. Above an hour the timer reads in hours and minutes; below an hour, minutes and seconds.

• Ice Pellet allowance and the 90-minute takeoff window. Allowance lookups for ice pellets and freezing precipitation are first-class — the app tracks the 90-minute takeoff window after precipitation stops and shows whether takeoff is still permitted.

• Active Frost handling. Between roughly −5 °C and +10 °C the app prompts for active frost and switches to the Active Frost allowance when applicable.

• Apple Watch companion. Run the timer from your wrist.

• Time display options. Local or Zulu, 12- or 24-hour clock — set once in Settings.

• Send Feedback / Get Help from the toolbar Menu now prefills the support email with your app version, iOS version, and device model — no more typing those out.

For pilots upgrading from version 1: your subscription carries over. The data tables and regulatory guidance are unchanged. The interface is what's different — and we think you'll find it considerably faster from question to answer. 2.0 Jun 15 Updated for 2025-2026 FAA and Transport Canada holdover documents. 1.9.6 11/02/2025 Fixed a bug where the precipitation type is not detected from a retrieved METAR. 1.9.5 12/05/2024 Updated data for the 2024-2025 winter season. 
Bug fixes.
Improved automatic METAR interpretation. 1.9.4 11/11/2024 Updated data for the 2023-2024 winter season. Squashed a few bugs, and improved user interface. 1.9.3 10/18/2023 Corrected display issue on iPhones. 
Added one week free trial before the annual subscription begins. New subscribers can try the app for a week. Cancel anytime before the promotional period ends. 1.9.2 11/17/2022 Fixed display bug on iPad. 1.9.1 11/03/2022 Data updated for FAA and Transport Canada Holdover Time Guidelines Winter 2022-2023 information. 1.9 10/23/2022 Updated with 2021-2022 FAA and Transport Canada data 1.8 11/10/2021 • Updated with 2020-2021 FAA and Transport Canada data
• Bug fixes
• Fixed display issues 1.7 10/07/2020 ● 2019-2020 FAA and Transport Canada data
● You don't think you have bugs? Guess again. Bugs are everywhere. We squashed a few little ones with this version. Give us feedback if you experience any. 1.6 09/18/2019 ● 2018-2019 FAA and Transport Canada data
● Here's the deal folks. Bugs are everywhere. We squashed a few little ones with this version. Give us feedback if you experience any.
● Fixed issue where app would occasionally crash when attempting to select a visibility.
● Fixed issue where nearby METAR may not be retrieved 1.5 12/20/2018 ● 2018-2019 data
● Bug fixes 1.4.2 12/13/2018 • 2017-2018 Holdover Data
• Here's the deal folks. We make little changes to the app in an effort to make sure your experience is the best it can be.Most of the time these bug fixes have nothing to do with the accuracy of the app. The changes are items you may not even notice, but we know they are there, so they get fixed
• Annual subscription is now an annual auto-renewing
• Bug fixes 1.4.1 11/07/2017 • Added Transport Canada holdover data
• Improved pop-up messages when OAT is below LOUT to inform user of ways to improve LOUT
• Times derived from FAA and Transport Canada 2016-2017 Holdover Chart Data
• The year of FAA and Transport Canada Holdover Time Guidelines used for calculations is now specified on the Info view (Select the menu button and then 'Info')
• Improved METAR evaluation to check for secondary precipitation types and present user with most restrictive precipitation
• Improved METAR evaluation when temperature is extremely low and dew point is not provided
• Display Bug fixes 1.4 01/22/2017 • Improved pop-up messages when OAT is below LOUT to inform user of ways to improve LOUT
• 2016-2017 Holdover Chart Data
• The year of FAA Holdover Time Guidelines used for calculations are now specified on the Info view (Select the menu button and then 'Info')
• Improved METAR evaluation to check for secondary precipitation types and present user with most restrictive precipitation
• Bug fixes 1.3.3 01/10/2017 • 2016-2017 Holdover Chart Data
• The year of FAA Holdover Time Guidelines used for calculations are now specified on the Info view (Select the menu button and then 'Info')
• Performance enhancements to the "Automatic Location Based METAR Search" option
• Improved interface during weather searches
• Added 'Cancel' button in the event that weather searches hang due to poor data connection
• Bug fixes 1.3.2 10/31/2016 • 2016-2017 Holdover Chart Data
• Bug fixes 1.3.1 10/14/2016 • 2016-2017 Holdover Chart Data
• Help/Instructions improved
• Data input display updated
• App efficiency improvements
• Minor bug fixes 1.3 10/11/2016