Accuracy classes and maximum permissible errors for trade measuring instruments (EU MID)
Accuracy classes and maximum permissible errors that Directive 2014/32/EU (the Measuring Instruments Directive) assigns to instruments used for trade in the EU. Each record is one instrument type at one accuracy class under one measurement condition, with the permitted error the directive states. Covers the ten instrument-specific annexes: water meters (MI-001), gas meters and volume conversion devices (MI-002), active electrical energy meters (MI-003), thermal energy meters (MI-004), measuring systems for liquids other than water including fuel dispensers and road tankers (MI-005), automatic weighing instruments (MI-006), taximeters (MI-007), material measures (MI-008), dimensional measuring instruments (MI-009) and exhaust gas analysers (MI-010). Answers 'what is the maximum permissible error for a water meter', 'what accuracy class does a petrol pump have to be', 'MID accuracy class for a taximeter', 'allowed error on a weighbridge', 'thermal energy meter accuracy class 2 MPE' and 'is my fuel dispenser within tolerance'. The values are condition-dependent -- the error allowed at low flow differs from the error allowed at high flow, and in-service limits differ from new-instrument limits -- so a single percentage figure is almost always the wrong answer. A deliberate mirror: there is one original, but the numbers sit in ten annexes of a 300,000-character legal text with no per-instrument row structure, and search engines currently answer this question from document-sharing sites and equipment vendors rather than from the directive.
Records70
Sources1
Verified2026-08-05
Review by2027-08-05
LicenceEU legislation reused under Commission Decision 2011/833/EU on the reuse of documents from the EU institutions. legislation.gov.uk content is Open Government Licence v3.0. Note the single-database volume advisory: one publisher supplies every record here, which is the EU/UK database right question -- mitigated by the source being legislation published under an explicit reuse decision.
The data
| Instrument type | Annex | Accuracy class | Condition | Maximum permissible error | Scope or member state option |
|---|---|---|---|---|---|
| Gas meter | IV | 1.0 | After durability test | Variation not exceeding one-third of MPE | MI-002. Class 1.0 durability test variation. |
| Water meter | III | N/A (single class) | After durability test, lower zone (Q1 to Q2) | Variation not exceeding 3 % of metered volume | MI-001. Durability test variation, lower zone. |
| Water meter | III | N/A (single class) | After durability test, upper zone (Q2 to Q4) | Variation not exceeding 1.5 % of metered volume | MI-001. Durability test variation, upper zone. |
| Gas meter | IV | 1.5 | After durability test, upper zone (Qt to Qmax) | Variation not exceeding 2 % | MI-002. Class 1.5 durability test variation. |
| Liquid measuring system (aircraft refuelling) | VII | 0.5 | Aircraft refuelling systems | 0.5 % | MI-005. Accuracy class for aircraft refuelling. |
| Automatic catchweigher | VIII | XI, XII, XIII, XIIII / Y(I), Y(II), Y(a), Y(b) | All loads, automatic operation | Per Tables 1-4 | MI-006. Eight accuracy classes for catchweighers. |
| Gas meters and volume conversion devices — volume conversion device | Annex IV (MI-002) | ambient temperature 20 °C ± 3 °C, ambient humidity 60 % ± 15 %, nominal values for power supply | ± 0,5 % | ||
| Dimensional measuring instruments — area measuring instruments | Annex XI (MI-009) | ± 1,0 %, but not less than 1 dm² | |||
| Dimensional measuring instruments — multidimensional measuring instruments | Annex XI (MI-009) | ± 1,0 d | d is the scale interval | ||
| Area measuring instrument | XI | N/A (single class) | Area of irregular shaped objects (e.g. leather) | 1.0 %, but not less than 1 dm2 | MI-009. Area measuring instrument MPE. |
| Material measures of length | Annex X (MI-008) | I | between two non-consecutive scale marks | ± (0,1 + 0,1 L) mm, where L is length rounded up to next whole metre; c = 0,1 mm for terminal interval bounded by a surface | |
| Material measure of length | X | I, II, III, D, S | Between two non-consecutive scale marks | Formula (a + bL) mm; class-dependent a and b values | MI-008. Length measure MPE formula. |
| Taximeters | Annex IX (MI-007) | calculation of the fare | ± 0,1 %, minimum including rounding: corresponding to the least significant digit of the fare indication | excluding any errors due to application of the taximeter in a taxi | |
| Thermal energy meters — calculator | Annex VI (MI-004) | calculator sub-assembly | E c = ± (0,5 + Δθmin/Δθ) | ||
| Exhaust gas analysers | Annex XII (MI-010) | 0 | CO fraction | ± 0,03 % vol or ± 5 %, whichever is greater | |
| Exhaust gas analyser | XII | 0 | CO fraction | +/- 0.03 % vol or +/- 5 %, whichever is greater | MI-010. Class 0 CO fraction MPE. |
| Exhaust gas analyser | XII | 0 and I | CO2 fraction | +/- 0.5 % vol or +/- 5 %, whichever is greater | MI-010. CO2 fraction MPE. |
| Thermal energy meter | VI | 1, 2, 3 | Complete instrument, rated operating conditions | Class-dependent formula | MI-004. Three accuracy classes. |
| Thermal energy meter | VI | 1, 2, 3 | Complete instrument | Formula-based per class (Ef + Et + Ec) | MI-004. MPE as percentage of true value. |
| Thermal energy meters | Annex VI (MI-004) | 1 | complete thermal energy meter | E = ± (2 + 4 Δθmin/Δθ + 0,01 qp/q) | E f , E t , E c according to points 7.1 to 7.3 |
| Liquid measuring system (cryogenic) | VII | 2.5 | Cryogenic liquids (temperature below -153 degrees C) | 2.5 % | MI-005. Accuracy class for cryogenic systems. |
| Active electrical energy meter | V | A, B, C | Different temperature ranges | Per Table 2, relevant range applies | MI-003. Temperature range selection. |
| Taximeters | Annex IX (MI-007) | distance travelled | ± 0,2 %, minimum value of mpe: 4 m | excluding any errors due to application of the taximeter in a taxi | |
| Taximeter | IX | N/A (single class) | Distance travelled measurement | +/- 0.2 %, minimum value 4 m | MI-007. Taximeter distance MPE. |
| Exhaust gas analyser | XII | 0 and I | Each fraction measured, rated operating conditions | Greater of absolute value or percentage of true value (per Table 2) | MI-010. Greater-of rule for MPEs. |
| Multidimensional measuring instrument | XI | N/A (single class) | Edge length of smallest enclosing rectangular parallelepiped | +/- 1.0 d (scale interval) | MI-009. Multidimensional measuring instrument MPE. |
| Gas meter | IV | 1.5 | Error after durability test | Not exceeding twice the MPE in point 2 | MI-002. Class 1.5 error after durability. |
| Water meter | III | N/A (single class) | Error after durability test, lower zone (Q1 to Q2) | +/- 6 % of metered volume | MI-001. Error after durability, lower zone. |
| Water meter | III | N/A (single class) | Error after durability test, upper zone (Q2 to Q4), cold water (0.1-30 degrees C) | +/- 2.5 % of metered volume | MI-001. Error after durability, upper zone, cold water. |
| Water meter | III | N/A (single class) | Error after durability test, upper zone (Q2 to Q4), hot water (30-90 degrees C) | +/- 3.5 % of metered volume | MI-001. Error after durability, upper zone, hot water. |
| Taximeter | IX | N/A (single class) | Fare calculation | +/- 0.1 %, minimum corresponding to least significant digit | MI-007. Taximeter fare calculation MPE. |
| Thermal energy meters — flow sensor | Annex VI (MI-004) | 1 | flow sensor sub-assembly | E f = ± (1 + 0,01 qp/q), but not more than 5 % | |
| Fuel dispenser (not liquefied gases) | VII | 0.5 | Fuel dispensers for non-liquefied-gas fuels | 0.5 % | MI-005. Accuracy class for fuel dispensers. |
| Gas meter | IV | N/A | Gas meter with temperature conversion, 30 degrees C range | MPE increased by 0.5 % | MI-002. Temperature conversion additional MPE. |
| Exhaust gas analysers | Annex XII (MI-010) | 0 | HC fraction | ± 10 ppm vol or ± 5 %, whichever is greater | |
| Exhaust gas analyser | XII | 0 | HC fraction | +/- 10 ppm vol or +/- 5 %, whichever is greater | MI-010. Class 0 HC fraction MPE. |
| Exhaust gas analyser | XII | N/A | Lambda value calculation | 0.3 % | MI-010. Lambda calculation MPE. |
| Liquid measuring system (liquefied carbon dioxide) | VII | 1.5 | Liquefied carbon dioxide | 1.5 % | MI-005. Accuracy class for liquefied CO2. |
| Liquid measuring system (liquefied gases, >= -10 C) | VII | 1.0 | Liquefied gases under pressure, temperature >= -10 degrees C | 1.0 % | MI-005. Accuracy class for liquefied gas systems. |
| Liquid measuring system (liquefied gases, < -10 C) | VII | 1.5 | Liquefied gases under pressure, temperature below -10 degrees C (not cryogenic) | 1.5 % | MI-005. Accuracy class for cold liquefied gas systems. |
| Water meter | III | N/A (single class) | Lower zone (Q1 to Q2 excluded), any water temperature | 5 % | MI-001. Volume measurement, lower zone. |
| Gas meter | IV | 1.5 | Lower zone (Qmin to Qt), volume or mass at metering conditions | 3 % | MI-002. Class 1.5 gas meter, lower zone MPE. |
| Length measuring instrument (for rope-type materials) | XI | I | Measurement of textiles, bands, cables, etc. | 0.125 %, but not less than 0.005 Lm | MI-009. Length measuring instrument Class I. |
| Liquid measuring system (milk) | VII | 0.5 | Milk measuring systems | 0.5 % | MI-005. Accuracy class for milk systems. |
| Exhaust gas analyser | XII | 0 and I | O2 fraction | +/- 0.1 % vol or +/- 5 %, whichever is greater | MI-010. O2 fraction MPE. |
| Gas meters and volume conversion devices — volume conversion device | Annex IV (MI-002) | other conversion devices at rated operating conditions | ± 1 % | ||
| Liquid measuring system (pipeline) | VII | 0.3 | Pipeline measuring systems | 0.3 % | MI-005. Accuracy class for pipeline systems. |
| Water meters | Annex III (MI-001) | Q1 ≤ Q < Q2 | ± 5 % | ||
| Water meters | Annex III (MI-001) | Q2 ≤ Q ≤ Q4, water temperature > 30 °C | ± 3 % | ||
| Liquid measuring system (other than water) | VII | 0.3, 0.5, 1.0, 1.5, 2.5 | Quantities >= 2 litres, measuring systems | 0.3 % to 2.5 % depending on accuracy class | MI-005. Five accuracy classes for measuring systems and meters. |
| Active electrical energy meter | V | A, B, C | Rated operating conditions at varying load current | Per Table 2 | MI-003. MPEs per class, temperature range, and load. |
| Volume conversion device (other type) | IV | N/A | Rated operating conditions | 1 % | MI-002. Other conversion device MPE. |
| Volume conversion device (temperature type) | IV | N/A | Rated operating conditions | 0.7 % | MI-002. Temperature conversion device MPE. |
| Active electrical energy meter | V | A, B, C | Rated operating conditions | Class-dependent, per Table 2 of Annex V | MI-003. Three class indices defined. |
| Exhaust gas analyser | XII | 0, I | Rated operating conditions | Per Table 2 of Annex XII | MI-010. Two classes defined. |
| Taximeter | IX | N/A (single class) | Real-time clock timekeeping | 0.02 % | MI-007. Taximeter clock accuracy. |
| Volume conversion device | IV | N/A | Reference conditions (20 degrees C +/- 3, 60% humidity +/- 15%) | 0.5 % | MI-002. Volume conversion device at reference conditions. |
| Liquid measuring system (road tankers, low viscosity) | VII | 0.5 | Road tanker systems, liquids of low viscosity (< 20 mPa.s) | 0.5 % | MI-005. Accuracy class for road tanker systems. |
| Automatic weighing instruments — automatic gravimetric filling instruments | Annex VIII (MI-006) | Ref(x) | static loads | 0,312 of the maximum permissible deviation of each fill from the average, as specified in Table 5, multiplied by the class designation factor (x) | |
| Automatic gravimetric filling instrument | VIII | Ref(x), X(x) | Static loads, rated operating conditions | 0.312 of max permissible deviation times factor (x) | MI-006. Filling instrument static weighing error. |
| Gas meters and volume conversion devices | Annex IV (MI-002) | 1,5 | temperature conversion, 30 °C range around specified temperature | MPE increased by 0,5 % | For a gas meter with temperature conversion, which only indicates the converted volume, the MPE of the meter is increased by 0,5 % in a range of 30 °C extending symmetrically around the temperature specified by the manufacturer that lies between 15 °C and 25 °C. |
| Gas meters and volume conversion devices — volume conversion device | Annex IV (MI-002) | temperature conversion devices at rated operating conditions | ± 0,7 % | ||
| Thermal energy meters — temperature sensor pair | Annex VI (MI-004) | temperature sensor pair sub-assembly | E t = ± (0,5 + 3 Δθmin/Δθ) | ||
| Taximeters | Annex IX (MI-007) | time elapsed | ± 0,1 %, minimum value of mpe: 0,2 s | excluding any errors due to application of the taximeter in a taxi | |
| Taximeter | IX | N/A (single class) | Time elapsed measurement | +/- 0.1 %, minimum value 0.2 s | MI-007. Taximeter time MPE. |
| Continuous totaliser | VIII | 0.5, 1, 2 | Totalised load | +/- 0.25 % to +/- 1.0 % depending on class | MI-006. Three accuracy classes for continuous totalisers. |
| Discontinuous totaliser | VIII | 0.2, 0.5, 1, 2 | Totalised load | +/- 0.10 % to +/- 1.00 % depending on class | MI-006. Four accuracy classes for discontinuous totalisers. |
| Water meter | III | N/A (single class) | Upper zone (Q2 included to Q4), water temperature <= 30 degrees C | 2 % | MI-001. Volume measurement, upper zone, cold water. |
| Gas meter | IV | 1.5 | Upper zone (Qt to Qmax), volume or mass at metering conditions | 1.5 % | MI-002. Class 1.5 gas meter, upper zone MPE. |
| Automatic rail weighbridge | VIII | 0.2, 0.5, 1, 2 | Weighing-in-motion, single wagon or total train | +/- 0.1 % to +/- 1.0 % depending on class | MI-006. Four accuracy classes for rail weighbridges. |
Where this came from
Every record above links the page it was taken from and quotes the sentence that states it. These are the 1 source this dataset was assembled from.
- eur-lex.europa.euhttps://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32014L0032
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.