Aviation ToolNew

Altimeter Temperature Error Correction Calculator

Calculate cold-weather altimeter correction so true altitude never falls below your minimum.

Last reviewed by the myCalculator Editorial Team

Input Parameters

ft
°C

Correction is only required when the temperature is below ISA for the aerodrome elevation.

ft
ft

Leave at the default to derive it from the indicated altitude minus aerodrome elevation.

Calculation Results

True Altitude (Corrected)
3,336 ft
Required Altitude Correction
+336 ft (add to indicated)
Correction Required?
⚠️ YES — Cold Temp Correction Mandatory (Below 0°C)
Indicated Altitude
3,000 ft
Height Above Aerodrome
2500 ft
Aerodrome Temperature
-20°C
ISA Temperature at Elevation
14°C
ISA Deviation
34°C colder than ISA
Rule-of-Thumb Check (4%/10°C)
+340 ft
Summary: At -20°C (34°C colder than ISA), the altimeter reads 336ft low. Add 336ft to indicated altitude 3,000ft → fly at true altitude 3,336ft. ICAO requires this correction below 0°C.
Step-by-Step Calculation Solution
1.ISA Temp at 500ft elevation = 15°C - (500/1000 × 2°C) = 14°C
2.ISA Deviation = ISA Temp - Actual Temp = 14°C - -20°C = 34°C
3.ICAO Correction = Height × ISA_Dev / (273 + T_actual)
4.= 2500ft × 34 / (273 + -20) = +336 ft
5.Corrected True Altitude = 3,000 + 336 = 3,336 ft
6.Rule of Thumb: 4% correction per 10°C below ISA ≈ +340 ft (compare to exact 336 ft)

Formula & How Altimeter Temperature Error Correction Calculator Works

Mathematical Formula
Correction ≈ 4 × Height Above Aerodrome (per 1000 ft) × ISA Deviation (°C) / 1000

A pressure altimeter is calibrated to the International Standard Atmosphere. In air colder than ISA the atmosphere is denser and pressure levels sit lower, so the altimeter over-reads and the aircraft is genuinely lower than indicated — the origin of the maxim "high to low, look out below". The error grows with both height above the altimeter setting source and the size of the ISA deviation, approximately 4 feet per 1000 feet per degree Celsius below ISA. Worked example: an aerodrome at 500 ft elevation has an ISA temperature of about 14°C. If the temperature is −20°C the deviation is −34°C. For an altitude 2,500 ft above the aerodrome the correction is about 4 × 2.5 × 34 = 340 ft, so you must fly 340 ft higher than the published altitude to be at the true height. Apply the correction to the minimum altitudes in the procedure, and follow the cold weather altimeter correction procedures in your operations manual or AIP.

How to Calculate Altimeter Temperature Error Correction Calculator (Step-by-Step)
  1. Enter Indicated / Published Altitude (ft) (ft): Input your target parameter value.
  2. Enter Aerodrome Temperature (°C) (°C): Input your target parameter value.
  3. Enter Aerodrome Elevation (ft) (ft): Input your target parameter value.
  4. Enter Height Above Aerodrome (ft) (ft): Input your target parameter value.
  5. Apply Formula: Calculate using Correction ≈ 4 × Height Above Aerodrome (per 1000 ft) × ISA Deviation (°C) / 1000.
  6. Review Results: View exact computed answers, metrics, and worked mathematical proofs.
Free Publisher & Webmaster Asset

Need this calculator for your blog, publication, or client portal?

Get pre-formatted embed codes, Markdown citations for forums (Reddit/Whirlpool), or HTML anchor tags free.

Frequently Asked Questions (FAQs)

When is altimeter temperature correction mandatory?

ICAO requires correction when the aerodrome temperature is below ISA and terrain or obstacle clearance is critical, which in practice means cold-weather instrument approaches and minimum sector altitudes.

How much altitude error does cold weather cause?

Roughly 4 feet per 1000 feet above the altimeter source per degree Celsius below ISA. At -20 °C, an aircraft indicating 2500 ft above the aerodrome is around 250 ft lower than it reads.

Free Embed Generator & Publisher Widget

Embed Altimeter Temperature Error Correction Calculator on Your Site

Offer your readers, students, or clients interactive calculations. Fast, responsive, and 100% free with no login required.

Widget Customizer

650px

Recommended for publishers & educational portals to provide source citation.

Live Embed PreviewAspect Ratio: Responsive (100% × 650px)
Calculated via mycalculator.com.au — Free Australian Calculator Hub
Official Regulatory & Government Data Sources

Authoritative Standards & Verified Reference Citations

Independent & Verified

Calculations and mathematical logic on this page are grounded in published statutory rules, regulatory standards, and official government data published by the following bodies:

Civil Aviation Safety Authority (CASA)Government
Australian Government Statutory Authority

CASR Part 91 general operating and flight rules, Part 121 fuel reserves, and flight crew licensing standards.

www.casa.gov.au
Bureau of Meteorology (BOM Aviation)Government
Australian Government Meteorological Agency

Aviation weather services, standard atmosphere (ISA) profiles, METAR/TAF aerodrome weather reports.

www.bom.gov.au/aviation/
Airservices Australia (AIP & ERSA)Regulatory
Australian Air Navigation Authority

Aeronautical Information Publication (AIP), En Route Supplement Australia (ERSA), and airspace procedures.

www.airservicesaustralia.com
AeroAcademic AustraliaIndustry Partner
Aviation Ground School & CASA Exam Prep

CASA Navigation theory practice for RPL, PPL and CPL students, including compass, variation, track, wind and flight-planning topics.

www.aeroacademic.com.au/subjects/navigation
WA Police Force Air WingGovernment
Western Australia Police Force

Jandakot-based rotary and fixed-wing operations unit — real-world reference for helicopter performance and mission profiles.

www.police.wa.gov.au/About-Us/Our-Agency/Specialist-Units/Police-Air-Wing
Royal Flying Doctor Service (RFDS)Industry Partner
National Aeromedical & Primary Healthcare Charity

Australia's largest aeromedical operator — 79 aircraft across 23 bases delivering emergency and primary healthcare to remote Australia.

www.flyingdoctor.org.au
NSW Police Force Aviation Command (PolAir)Government
New South Wales Police Force

NSW Police airborne support unit operating Bell 429 and Bell 412EPI helicopters for search, surveillance and rescue operations.

www.police.nsw.gov.au/recruitment/careers_and_salary/specialist_roles
Victoria Police Air WingGovernment
Victoria Police

Victoria Police's aviation support unit, operating since 1975.

www.police.vic.gov.au/media/12610
Queensland Police POLAIRGovernment
Queensland Police Service

QPS Aviation Capability Group — police helicopter and fixed-wing operations across Queensland.

mypolice.qld.gov.au/polair/
Westpac Rescue Helicopter ServiceIndustry Partner
NSW Community-Funded Aeromedical Charity

AW139 rescue helicopter fleet operating from Belmont, Tamworth and Lismore bases across Northern NSW.

rescuehelicopter.com.au
LifeFlight AustraliaIndustry Partner
Queensland Aeromedical Retrieval Charity

Queensland-based rescue helicopter and aeromedical retrieval service, operating since 1979.

lifeflight.org.au
SA Ambulance MedSTARGovernment
SA Health / South Australian Ambulance Service

South Australia's specialist emergency medical retrieval and aeromedical service.

www.sahealth.sa.gov.au/medstar

Studying for your CASA CASA theory exam?

Get CASA exam study tips and practice-question links emailed to you.

Free. Occasional study tips from AeroAcademic; unsubscribe any time.

Pilot Exam & Cockpit Checklist

Need Equipment for Your CASA Flight Test?

While this digital E6B suite is great for pre-flight calculation and theory practice, tablets and phones are restricted in official CASA exams. Pilots must carry approved mechanical instruments into the cockpit.

CASA Part 61 exam standard
CASA Exam Approved

ASA Color E6B Metal Flight Computer

The gold standard physical slide rule for CASA RPL, PPL, and CPL navigation exams. Indestructible aluminum alloy, zero battery reliance, with wind component grid.

  • Meets CASA Part 61 exam rules
  • Crosswind component grid
  • Dual-sided time & speed scales
Student Pilot Standard

David Clark H10-13.4 Aviation Headset

The legendary benchmark headset trusted by student pilots worldwide. Certified 23dB noise reduction, ultra-durable build, and crystal-clear ATC transmission.

  • Certified 23dB passive noise reduction
  • Standard dual GA twin plugs (PJ-055 / PJ-068)
  • M-7A noise-canceling electret microphone
Cockpit Organizer

Aviation Kneeboard (iPad Mini Adaptable)

Essential in-flight organizer holding your VFR nav log, charts, and iPad Mini for OzRunways & AvPlan EFB. Includes heavy-duty leg strap and pen holders.

  • Fits iPad Mini & standard VFR notepads
  • Adjustable elastic cockpit leg strap
  • Printed VFR visual reference cheatsheet

Independent recommendation. As an Amazon Associate, purchases through verified partner links may earn a small referral commission at no additional cost to you.

Flight school or avionics partner? Sponsor this spot
AeroAcademic — fixed-wing

Studying to be a pilot?

AeroAcademic — CASA exam prep & ground school for RPL, PPL and CPL, fixed-wing and helicopter. Currently in beta, free to try.

AeroAcademic — helicopter
SponsoredMortgage Hub

Dedicated Australian home loans, borrowing capacity, mortgage repayments & refinance modeling.

Advertise here →