Hand-arm vibration (HAVS) calculator
Add the tools used in a shift to get the daily vibration exposure in m/s² A(8) and HSE exposure points, with a clear traffic-light check against the action and limit values.
Daily exposure calculator
Add each vibrating tool a worker uses in the day and the trigger time (the time the tool is actually running in the hand, not the whole task). Pick a tool to autofill its typical HSE value, or choose Custom value to enter the manufacturer's declared or a measured figure.
What your result means
The Control of Vibration at Work Regulations 2005 set two daily thresholds, both expressed as A(8): the daily vibration dose averaged over an eight-hour working day. The exposure action value (EAV) is 2.5 m/s² A(8), or 100 points. The exposure limit value (ELV) is 5 m/s² A(8), or 400 points.
Below the EAV
Under 100 points (under 2.5 m/s²)
Risk is lower, but not zero. Keep exposure as low as is reasonably practicable. Some susceptible workers can still develop symptoms near the EAV over a few years.
At or above the EAV
100 to 399 points (2.5 to 5 m/s²)
A clear risk that must be managed. Reduce exposure as far as reasonably practicable, provide information and training, and put the worker under health surveillance.
At or above the ELV
400 points or more (5 m/s² or more)
A high risk. Employees must not be exposed above the ELV. Stop, change the tool, the method, or the trigger time so the day's exposure comes back below the limit.
Health surveillance is required at or above the EAV. Certain cases of HAVS and all cases of vibration-related carpal tunnel syndrome (CTS) are reportable to HSE under RIDDOR (the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 2013).
Typical tool vibration values
HSE typical values for common tools. The last two columns show how quickly a single tool at its typical value reaches the EAV and ELV on its own, from the exposure points system. A tool you select in the calculator is highlighted here.
| Tool | Typical range | Typical value | Time to EAV | Time to ELV |
|---|---|---|---|---|
| Breakers & hammers | ||||
| Pneumatic / road breaker | 10 to 29 m/s² | 25 m/s² | 5 min | 19 min |
| Electric / hydraulic breaker | 7 to 18 m/s² | 14 m/s² | 15 min | 1 h 1 min |
| Demolition / rotary hammer | 10 to 21 m/s² | 18 m/s² | 9 min | 37 min |
| Rock drill | 10 to 28 m/s² | 26 m/s² | 4 min | 18 min |
| Chipping hammer (weld) | 20 to 32 m/s² | 31 m/s² | 3 min | 12 min |
| Chipping hammer (stone / concrete) | 11 to 22 m/s² | 20 m/s² | 8 min | 30 min |
| Stone hammer | 7 to 22 m/s² | 18 m/s² | 9 min | 37 min |
| Scabbler | 4 to 14 m/s² | 12 m/s² | 21 min | 1 h 23 min |
| Drills | ||||
| Drill (standard bit) | 2 to 5 m/s² | 5 m/s² | 2 h | 8 h |
| Drill (hole saw) | 4 to 12 m/s² | 10 m/s² | 30 min | 2 h |
| Core drill (78 to 107 mm) | 6 to 8 m/s² | 8 m/s² | 47 min | 3 h 8 min |
| Impact drill (masonry bit) | 7 to 13 m/s² | 11 m/s² | 25 min | 1 h 39 min |
| Grinders | ||||
| Angle grinder (100 to 180 mm) | 3 to 10 m/s² | 7 m/s² | 1 h 1 min | 4 h 5 min |
| Angle grinder (flapper disc) | 2 to 5 m/s² | 4 m/s² | 3 h 8 min | 10+ h |
| Angle grinder (220 to 300 mm) | 4 to 11 m/s² | 9 m/s² | 37 min | 2 h 28 min |
| Die grinder | 5 to 10 m/s² | 8 m/s² | 47 min | 3 h 8 min |
| Straight grinder | 4 to 9 m/s² | 8 m/s² | 47 min | 3 h 8 min |
| Pedestal grinder | 2 to 11 m/s² | 8 m/s² | 47 min | 3 h 8 min |
| Angle polisher (mop / pad) | 1 to 3 m/s² | 3 m/s² | 5 h 33 min | 10+ h |
| Saws & cutting | ||||
| Reciprocating saw | 7 to 27 m/s² | 18 m/s² | 9 min | 37 min |
| Cut-off saw (masonry) | 5 to 14 m/s² | 13 m/s² | 18 min | 1 h 11 min |
| Jigsaw | 9 to 17 m/s² | 11 m/s² | 25 min | 1 h 39 min |
| Nibbler | 7 to 12 m/s² | 12 m/s² | 21 min | 1 h 23 min |
| Scaling & sanding | ||||
| Needle scaler (standard) | 12 to 26 m/s² | 19 m/s² | 8 min | 33 min |
| Needle scaler (vibration-reduced) | 3 to 8 m/s² | 7 m/s² | 1 h 1 min | 4 h 5 min |
| Random-orbital sander | 6 to 14 m/s² | 12 m/s² | 21 min | 1 h 23 min |
| Orbital sander | 4 to 12 m/s² | 9 m/s² | 37 min | 2 h 28 min |
| Compaction & fixing | ||||
| Plate compactor (standard) | 9 to 22 m/s² | 18 m/s² | 9 min | 37 min |
| Plate compactor (vibration-reduced) | 2 to 7 m/s² | 4 m/s² | 3 h 8 min | 10+ h |
| Impact wrench (3/8 to 3/4 in) | 3 to 6 m/s² | 5 m/s² | 2 h | 8 h |
| Impact wrench (1 in) | 7 to 11 m/s² | 10 m/s² | 30 min | 2 h |
| Nail gun / stapler | 2 to 6 m/s² | 4 m/s² | 3 h 8 min | 10+ h |
| Grounds & forestry | ||||
| Chainsaw | 3 to 7 m/s² | 7 m/s² | 1 h 1 min | 4 h 5 min |
| Brushcutter (saw head) | 3 to 5 m/s² | 5 m/s² | 2 h | 8 h |
| Strimmer (line head) | 2 to 7 m/s² | 7 m/s² | 1 h 1 min | 4 h 5 min |
| Hedge trimmer | 3 to 14 m/s² | 7 m/s² | 1 h 1 min | 4 h 5 min |
| Mower (hand-guided) | 3 to 8 m/s² | 6 m/s² | 1 h 23 min | 5 h 33 min |
| Mower (ride-on) | 3 to 6 m/s² | 5 m/s² | 2 h | 8 h |
| Other | ||||
| Water jetting gun | 1 to 5 m/s² | 4 m/s² | 3 h 8 min | 10+ h |
| Router | 2 to 3 m/s² | 3 m/s² | 5 h 33 min | 10+ h |
Values from HSE's vibration risk assessment guidance. Times assume the tool is the only source of exposure that day; combining tools reaches the values sooner. "10+ h" means the value is not reached within a normal working day at that vibration level.
Exposure points ready reckoner
The HSE points system lets you add exposure across tools without a spreadsheet. Read the points per hour for the tool's vibration, multiply by the trigger time in hours, then add the points from every tool used that day.
| Tool vibration (m/s²) | Points per hour | Reaches EAV (100) after | Reaches ELV (400) after |
|---|---|---|---|
| 3 | 20 | 5 h 33 min | 10+ h |
| 4 | 30 | 3 h 8 min | 10+ h |
| 5 | 50 | 2 h | 8 h |
| 6 | 70 | 1 h 23 min | 5 h 33 min |
| 7 | 100 | 1 h 1 min | 4 h 5 min |
| 10 | 200 | 30 min | 2 h |
| 12 | 300 | 21 min | 1 h 23 min |
| 15 | 450 | 13 min | 53 min |
Points per hour are HSE's rounded ready-reckoner figures. The calculator above uses the precise formula, so its totals can differ slightly from a hand calculation with these rounded numbers.
How the calculation works
Two equivalent ways to express the same daily exposure. A(8) is the formal measure in the regulations; points are the practical way to add it up on site.
Daily exposure A(8)
For one tool, the partial exposure is the vibration magnitude scaled by the square root of the trigger time over an 8-hour reference:
A(8)partial = a × √(T ÷ 8)
where a is the vibration in m/s² and T is the trigger time in hours. For several tools, the daily A(8) is the square root of the sum of the squared partial exposures.
Exposure points
Points rise with the square of the vibration and in proportion to time, so they add up directly across tools:
points = 2 × a² × T
100 points equals the EAV (2.5 m/s²) and 400 points equals the ELV (5 m/s²). Total points and A(8) are linked by A(8) = √(points ÷ 16), which is how this tool converts between the two.
Reducing exposure on site
The two levers are lower vibration and less trigger time. Both reduce points; squaring the magnitude means a small drop in vibration cuts exposure sharply.
Cut the magnitude, not just the time
Because points scale with the square of the vibration, swapping a 19 m/s² standard needle scaler for a 7 m/s² vibration-reduced one cuts the points to roughly an eighth for the same trigger time. Choosing lower-vibration kit when you buy or hire usually does more than rationing minutes.
The 15-minute and one-hour rule of thumb
HSE's quick guide: a worker using a hammer-action tool (breaker, demolition hammer) is likely to reach the EAV after about 15 minutes of trigger time and the ELV after about an hour. Non-hammer tools such as grinders reach the EAV after about an hour and the ELV after about four hours. If a breaker is running for most of a shift, you are almost certainly over the limit.
Anti-vibration gloves are not a control
Gloves marked to BS EN ISO 10819 keep hands warm and protect against cuts, but they do not reliably reduce the vibration that causes HAVS and must not be used to lower a calculated exposure. Keep hands warm and dry to maintain circulation, but rely on lower-vibration tools, job rotation, and limiting trigger time for the actual control.
Rotate the work, log the trigger time
Sharing a high-vibration task between operatives spreads the points so no individual goes over. To do that credibly you need real trigger times, not whole-task durations. A breaker that runs for 20 minutes inside a two-hour task is 20 minutes of exposure, not two hours. Time the running tool, or fit a logger, and keep the record with the risk assessment.
Sources
- The Control of Vibration at Work Regulations 2005, regulation 4 (exposure limit value and action value)
- HSE INDG175: Hand-arm vibration at work, a brief guide (EAV, ELV, employer duties, rules of thumb)
- HSE: Hand-arm vibration risk assessment (typical tool values and the exposure points ready reckoner)
- HSE: Hand-arm vibration exposure calculator (the official spreadsheet this tool mirrors)
- HSE L140 Hand-arm vibration, Control of Vibration at Work Regulations 2005, guidance on regulations
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