How far off a US fuel pump, LPG meter or EV charger is allowed to be (NIST Handbook 44)
The accuracy every commercial device that sells fuel or energy in the United States has to hold, taken from NIST Handbook 44 -- the specifications and tolerances that state weights-and-measures programs adopt by reference and enforce when they inspect a gas pump. Each record is one row of one tolerance table: the commodity or device the row covers, its accuracy class, and the three limits the handbook prints for it. Answers 'how accurate does a gas pump have to be' (a retail petrol or diesel dispenser is Accuracy Class 0.5: 0.5 % once in service, 0.3 % when newly installed), 'is a new dispenser held to a tighter standard than one already in service' (yes -- the acceptance tolerance for a new or newly repaired device is tighter than the maintenance tolerance that applies afterwards), and the same question for propane, anhydrous ammonia, CNG, hydrogen, liquid CO2, cryogenic products and EV chargers. Covers Handbook 44 sections 3.30 (liquid-measuring devices), 3.31 (vehicle-tank meters), 3.32 (LPG and anhydrous ammonia), 3.33 (hydrocarbon gas vapor), 3.34 (cryogenic), 3.37 (mass flow meters), 3.38 (carbon dioxide), 3.39 (hydrogen) and 3.40 (electric vehicle fueling systems). Three things to read alongside the numbers. First, the handbook footnotes that special test tolerances do not apply to retail motor fuel or retail Diesel Exhaust Fluid dispensers at all, so the special-test column in section 3.30 is not a limit a filling-station pump is held to; that footnote is carried here as its own record. Second, the Accuracy Class 0.5 percentages stop applying on a small test draft: in section 3.30, a draft of 40 L (10 gal) or less is held to a volume figure instead of a percentage, and in section 3.31 to 6 in3 for a 5 gallon draft and 11 in3 for a 10 gallon one. The section 3.30 version of that exception is a record here. Third, this is a first pass over a source published only as a PDF: a table row is included only where the device, the class and the printed limits sit in one continuous run of text, so a handful of rows whose bullets are split across a page break by the PDF's running footer are not yet here -- section 3.30's Accuracy Class 0.3 row is the notable omission, and the equivalent row is present from sections 3.31 and 3.37. Nothing is reconstructed across a break; a row we cannot quote whole is left out.
The data
| Device or commodity | Accuracy class | Acceptance tolerance (new or newly repaired device) | Maintenance tolerance (device already in service) | Special test tolerance | Handbook 44 section | Edition | Condition |
|---|---|---|---|---|---|---|---|
| Asphalt at temperatures greater than 50 °C (122 °F) | 0.3A | 0.3 % | 0.3 % | 0.5 % | 3.30. Liquid-Measuring Devices | 2026 | |
| Agri-chemical liquids | 0.5 | 0.3 % | 0.5 % | 0.5 % | 3.30. Liquid-Measuring Devices | 2026 | |
| Petroleum products delivered from small capacity (at 4 L/min (1 gpm) through 115 L/min or 30 gpm)** motor-fuel devices | 0.5 | 0.3 % | 0.5 % | 0.5 % | 3.30. Liquid-Measuring Devices | 2026 | |
| Devices designed to deliver less than 1 gal | 1.1 | 0.75 % | 1.0 % | 1.25 % | 3.30. Liquid-Measuring Devices | 2026 | |
| test drafts ≤ 40 L or 10 gal | 0.5 | one-half the maintenance tolerance values | 20 mL plus 4 mL per indicated liter or 1 in3 plus 1 in3 per indicated gallon | 3.30. Liquid-Measuring Devices | 2026 | normal and special tests | |
| retail motor fuel and retail Diesel Exhaust Fluid (DEF) dispensers | not applicable | 3.30. Liquid-Measuring Devices | 2026 | ||||
| Asphalt at temperatures greater than 50 °C | 0.3A | 0.3 % | 0.3 % | 0.5 % | 3.31. Vehicle-Tank Meters | 2026 | |
| Petroleum products delivered from large capacity (flow rates over 115 L/min or 30 gpm)** devices, including motor-fuel devices | 0.3 | 0.15 % | 0.3 % | 0.45 % | 3.31. Vehicle-Tank Meters | 2026 | |
| Petroleum products delivered from small capacity (at 4 L/min (1 gpm) through 115 L/min or 30 gpm)** motor-fuel devices | 0.5 | 0.3 % | 0.5 % | 0.5 % | 3.31. Vehicle-Tank Meters | 2026 | |
| Devices designed to deliver less than 4 L (1 gal) | 1.1 | 0.75 % | 1.0 % | 1.25 % | 3.31. Vehicle-Tank Meters | 2026 | |
| 5 gal and 10 gal test drafts | 0.5 | 3 in3 and 5.5 in3 | 6 in3 and 11 in3 | 3.31. Vehicle-Tank Meters | 2026 | normal and special tests | |
| Water | 1.5 | 1.5 % | 1.5 % | 1.5 % | 3.31. Vehicle-Tank Meters | 2026 | Overregistration |
| Water | 1.5 | 1.5 % | 1.5 % | 5.0 % | 3.31. Vehicle-Tank Meters | 2026 | Underregistration |
| Anhydrous ammonia, LPG | 1.0 | 0.6 % | 1.0 % | 1.0 % | 3.32. LPG and Anhydrous Ammonia Liquid-Measuring Devices | 2026 | |
| Gases at low pressure | 3.0 | 1.5 % | 1.5 % | 3.33. Hydrocarbon Gas Vapor-Measuring Devices | 2026 | Overregistration | |
| Gases at low pressure | 3.0 | 3.0 % | 3.0 % | 3.33. Hydrocarbon Gas Vapor-Measuring Devices | 2026 | Underregistration | |
| Cryogenic products; liquefied compressed gases | 2.5 | 1.5 % | 2.5 % | 2.5 % | 3.34. Cryogenic Liquid-Measuring Devices | 2026 | |
| Asphalt at temperatures greater than 50 °C | 0.3A | 0.3 % | 0.3 % | 0.5 % | 3.37. Mass Flow Meters | 2026 | |
| Large capacity motor-fuel dispensers | 0.3 | 0.2 % | 0.3 % | 0.5 % | 3.37. Mass Flow Meters | 2026 | |
| Small capacity (retail) motor-fuel dispensers | 0.5 | 0.3 % | 0.5 % | 0.5 % | 3.37. Mass Flow Meters | 2026 | |
| Anhydrous ammonia | 1.0 | 0.6 % | 1.0 % | 1.0 % | 3.37. Mass Flow Meters | 2026 | |
| LP Gas (including vehicle-tank meters) | 1.0 | 0.6 % | 1.0 % | 1.0 % | 3.37. Mass Flow Meters | 2026 | |
| Compressed natural gas as a motor-fuel | 2.0 | 1.5 % | 2.0 % | 2.0 % | 3.37. Mass Flow Meters | 2026 | |
| Cryogenic liquid meters | 2.5 | 1.5 % | 2.5 % | 2.5 % | 3.37. Mass Flow Meters | 2026 | |
| Liquefied compressed gases other than LP Gas | 2.5 | 1.5 % | 2.5 % | 2.5 % | 3.37. Mass Flow Meters | 2026 | |
| Liquid carbon dioxide | 2.5 | 1.5 % | 2.5 % | 2.5 % | 3.38. Carbon Dioxide Liquid-Measuring Devices | 2026 | |
| Hydrogen gas as a vehicle fuel | 7.0 | 5.0 % | 7.0 % | 3.39. Hydrogen Gas-Measuring Devices | 2026 | ||
| a DC system that was placed in service prior to January 1, 2025, and that is marked Class 5 | 5.0 % | 5.0 % | 3.40. Electric Vehicle Fueling Systems | 2026 | acceptance and maintenance tolerances | ||
| any DC system not subject to paragraph T.2.2.(a) | 1.0 % | 2.0 % | 3.40. Electric Vehicle Fueling Systems | 2026 | |||
| EVSE load tests for AC Systems | 1.0 % | 2.0 % | 3.40. Electric Vehicle Fueling Systems | 2026 |
Where this came from
Every record above links the page it was taken from and quotes the sentence that states it. These are the 9 sources this dataset was assembled from.
- nist.govhttps://www.nist.gov/document/2026-nist-handbook-44-section-330
- nist.govhttps://www.nist.gov/document/2026-nist-handbook-44-section-331
- nist.govhttps://www.nist.gov/document/2026-nist-handbook-44-section-332
- nist.govhttps://www.nist.gov/document/2026-nist-handbook-44-section-333
- nist.govhttps://www.nist.gov/document/2026-nist-handbook-44-section-334
- nist.govhttps://www.nist.gov/document/2026-nist-handbook-44-section-337
- nist.govhttps://www.nist.gov/document/2026-nist-handbook-44-section-338
- nist.govhttps://www.nist.gov/document/2026-nist-handbook-44-section-339
- nist.govhttps://www.nist.gov/document/2026-nist-handbook-44-section-340
Machine-readable
- data.jsonThe whole dataset — every record with its source URL and source quote.
- Open Knowledge Format bundleOne JSON object per line — every record's frontmatter and quoted span exactly as it is held here, in one fetch.
- How this is made and checkedWhat "verified against source" does and does not mean.
From your own code
Same records, same quotes, without scraping the page: refsource is on PyPI and npm. Each value comes back carrying the URL it was read from and the sentence on that page that states it — .source and .quote sit on the value itself rather than in a side channel, so the checking step is available instead of skipped.
pip install refsource
refsource lookup motor-fuel-dispenser-measurement-tolerances-nist accuracy_class=0.3A
npx -y refsource lookup motor-fuel-dispenser-measurement-tolerances-nist accuracy_class=0.3A