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Free HAVS calculator
Work out daily hand-arm vibration exposure in HSE exposure points and A(8). Add each tool and its trigger time to see the result instantly. Free, no sign-up.
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Calculate daily vibration exposure
Select your tool, enter the vibration magnitude and how long you use it.
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Save assessments for every operative, see who is near the action or limit value, and keep the records you need for health surveillance. No hardware, no quotes.
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The HSE exposure points method
Daily vibration exposure depends on how strongly a tool vibrates and how long it is used. The HSE gives two equivalent ways to express it.
Exposure points
points = 2 × a² × T
a is the vibration magnitude in m/s² and T is trigger time in hours. Points from each tool simply add up.
A(8) daily exposure
A(8) = a × √(T ÷ 8)
For several tools, combine them: A(8) = √(A₁(8)² + A₂(8)² + …). 100 points is the same as 2.5 m/s² A(8).
Worked example
An operative uses a large angle grinder (8 m/s²) for 1 hour 30 minutes of trigger time, then a hammer drill (9 m/s²) for 30 minutes.
| Tool | Vibration | Trigger time | Points | Partial A(8) |
|---|---|---|---|---|
| Angle grinder | 8 m/s² | 1h 30m | 2 × 8² × 1.5 = 192 | 3.46 m/s² |
| Hammer drill | 9 m/s² | 30m | 2 × 9² × 0.5 = 81 | 2.25 m/s² |
| Daily total | 2h 00m | 273 points | 4.13 m/s² |
Action required 273 points is above the exposure action value (100) but below the limit value (400), so exposure must be reduced as far as reasonably practicable and health surveillance provided.
How quickly tools reach the action and limit values
Exposure points per hour of trigger time, and how long one tool takes on its own to reach 100 points (EAV) and 400 points (ELV).
| Vibration (m/s²) | Points per hour | Action value (100) after | Limit value (400) after |
|---|---|---|---|
| 2.5 | 13 | 8h 00m | over 24h |
| 3 | 18 | 5h 33m | 22h 13m |
| 4 | 32 | 3h 08m | 12h 30m |
| 5 | 50 | 2h 00m | 8h 00m |
| 6 | 72 | 1h 23m | 5h 33m |
| 7 | 98 | 1h 01m | 4h 05m |
| 8 | 128 | 47m | 3h 08m |
| 9 | 162 | 37m | 2h 28m |
| 10 | 200 | 30m | 2h 00m |
| 12 | 288 | 21m | 1h 23m |
| 15 | 450 | 13m | 53m |
| 20 | 800 | 8m | 30m |
| 25 | 1250 | 5m | 19m |
What your result means
Set by the Control of Vibration at Work Regulations 2005.
Below 100 points
Under 2.5 m/s² A(8). Keep exposure as low as reasonably practicable.
100 points or more
The exposure action value. Reduce exposure and provide health surveillance.
400 points or more
The exposure limit value: 5.0 m/s² A(8). It must not be exceeded.
Typical vibration values for common tools
Starting points from published guidance. Use a measured or manufacturer's value for your own tool where you have one.
| Tool | Vibration (m/s²) | Source |
|---|---|---|
| Angle grinder (large, vibration-reduced) | 4 | HSE in use |
| Angle grinder (large, other) | 8 | HSE in use |
| Hammer drill / combi hammer | 9 | HSE in use |
| Road breaker (typical) | 12 | HSE in use |
| Demolition hammer (typical) | 15 | HSE in use |
| Needle scaler (older design) | up to 25 | HSE in use |
| Chainsaw | 6 | HSE in use |
| Random orbital sander | 7–10 | HSE in use |
| Jigsaw | 11.2 | EU guide / OPERC |
| Reciprocating saw | 20.7 | EU guide / OPERC |
| Impact wrench | 7.1 | EU guide / OPERC |
| Stonehammer (D handle) | 19 | HSE initial value |
Sources: HSE stonemasonry Table 1, HSE values measured in use, and the EU Good Practice Guide / OPERC wall chart. See Guidance for more.
HAVS calculator questions
What is a HAVS calculator?
A HAVS calculator works out a person's daily exposure to hand-arm vibration from the tools they use. You enter each tool's vibration magnitude in m/s² and its trigger time, and it gives the daily exposure in HSE exposure points and as an A(8) value, then compares it with the exposure action value and exposure limit value.
How are HAVS exposure points calculated?
HSE exposure points are calculated as 2 × a² × T, where a is the vibration magnitude in m/s² and T is the trigger time in hours. Points from every tool used in the day are added together. 100 points equals the exposure action value and 400 points equals the exposure limit value.
What is A(8)?
A(8) is the daily vibration exposure averaged over a standard 8-hour day, in m/s². For one tool it is a × √(T ÷ 8). For several tools, the partial A(8) values are combined as the square root of the sum of their squares.
What are the exposure action and limit values?
Under the Control of Vibration at Work Regulations 2005, the exposure action value (EAV) is 2.5 m/s² A(8), equal to 100 points, and the exposure limit value (ELV) is 5.0 m/s² A(8), equal to 400 points. Above the EAV employers must reduce exposure and provide health surveillance; the ELV must not be exceeded.
What vibration value should I use for my tool?
Use an in-use measurement for the tool if you have one, otherwise the manufacturer's declared value, ideally with an allowance for real working conditions. The tool list in this calculator gives typical values from HSE and EU guidance to start with.
Is trigger time the same as time on the job?
No. Trigger time is only the time the tool is actually running in your hands. It is usually much shorter than the time spent on the task, and HSE recommends observing it rather than relying on estimates.
Is this HAVS calculator free?
Yes. The calculator on this page is free to use and nothing you enter is stored. If you need to keep records for a team, the HAVS System saves assessments for every operative and has a 7-day free trial.
Why you can rely on it
Managing vibration risk for a team?
The HAVS System keeps every assessment in one place, flags who is near the action or limit value, and has reports ready for health surveillance.