Methamphetamine Calculator NZPHF Science (Formerly ESR)
Understand how methamphetamine surface-testing results are interpreted, with access to the independent PHF Science calculator and EnviroCheck's professional testing services.
Understanding Methamphetamine Contamination Results
EnviroCheck Forensics has been involved in independent methamphetamine contamination testing in New Zealand since 2011.
PHF Science, formerly the Institute of Environmental Science and Research (ESR), has developed a scientific calculator based on experimental research into methamphetamine manufacture and use.
The calculator provides an additional educational resource for understanding methamphetamine surface contamination.
PHF Science confirmed in October 2026 that the experimental data underlying its calculator remains relevant and has not required updating in response to New Zealand's 2026 methamphetamine regulations.
The calculator does not replace professional testing, laboratory analysis or assessment against applicable regulatory requirements.
Need Professional Methamphetamine Testing?
EnviroCheck provides independent methamphetamine testing for homebuyers, landlords, property managers and property owners throughout New Zealand.
View the PHF Science Methamphetamine Calculator
The PHF Science methamphetamine calculator is hosted on the official PHF Science website. The link below opens in a new tab so you can return to EnviroCheck to book professional testing.
View PHF Science Methamphetamine CalculatorPHF Science Disclaimer
The New Zealand Institute for Public Health and Forensic Science Limited (‘PHF Science’) has taken reasonable care in developing this calculator. However, no warranty is given as to the accuracy, completeness, reliability, or fitness for purpose of the calculator or any results generated through its use. To the extent permitted by law, PHF Science accepts no liability for any loss, damage, cost, or expense arising from the use.
How Methamphetamine Surface-Testing Results Are Reported
A laboratory methamphetamine test reports the amount of methamphetamine removed from a surface by a swab, expressed in micrograms per 100 square centimetres (µg/100 cm²). Each swab represents a single surface in a single location, so results can differ between rooms and even between surfaces within the same room.
Higher readings from locations that are difficult to reach — such as high walls, ceilings or the tops of cupboards — can be a better indicator of the amount of methamphetamine vapour a room has been exposed to, because those surfaces are less likely to have been cleaned between contamination and testing.
A calculator such as the PHF Science methamphetamine calculator can help put a single laboratory result into context by estimating the number of smoked doses that could account for the reading, given the room and swab area. It is an indicative guide only and does not establish whether a property is safe, compliant or contaminated under New Zealand's regulatory framework.
Lab-accredited results
Results should come from an ISO/IEC 17025 accredited laboratory using an approved NIOSH analytical method.
Surface location matters
Unreachable, high surfaces often give a clearer picture of vapour exposure than cleaned low surfaces.
Professional assessment
A calculator is educational; compliance decisions need independent professional testing and assessment.
Frequently Asked Questions
Common questions about the PHF Science methamphetamine calculator and understanding meth test results.
What is the PHF Science methamphetamine calculator?
The PHF Science methamphetamine calculator (formerly the ESR meth calculator) is a free online tool developed by PHF Science from experimental research into methamphetamine manufacture and use. It helps interpret a laboratory surface-testing result by estimating the number of smoked doses that could account for the contamination observed, using the swab area, room area and test value you enter.
Is ESR now PHF Science?
Yes. The Institute of Environmental Science and Research (ESR) is now PHF Science — the New Zealand Institute for Public Health and Forensic Science. The methamphetamine calculator previously known as the ESR meth calculator is now provided by PHF Science and continues to be available on the PHF Science website.
Does the PHF Science calculator replace professional testing?
No. The calculator is an educational resource only. It does not replace professional methamphetamine testing, laboratory analysis, or assessment against applicable New Zealand regulatory requirements. EnviroCheck provides independent methamphetamine testing throughout New Zealand for homebuyers, landlords, property managers and property owners.
Is the PHF Science calculator data still current?
PHF Science confirmed in October 2026 that the experimental data underlying its calculator remains relevant and has not required updating in response to New Zealand's 2026 methamphetamine regulations.
Does EnviroCheck provide the PHF Science calculator?
No. The calculator is owned and operated by PHF Science. EnviroCheck is an independent methamphetamine testing company and provides this page as an educational resource linking to the official PHF Science calculator. EnviroCheck is not endorsed by, accredited by, or affiliated with PHF Science.