This noise barrier calculator is free to use, with no account and no password. It runs entirely in your browser; enter your name and email to reveal your result, and we can send you a copy.
The tool predicts the sound pressure level at a receiver behind a barrier, per octave band, and compares it against the Indonesian environmental noise limit for the land-use zone you select. It handles a single barrier, two barriers in series, and a building acting as a thick barrier, and it reports the insertion loss the barrier actually buys you rather than just the final level.
Two calculation methods are offered, ISO 9613-2 and a CNOSSOS-EU style diffraction term. Source data can be entered as sound power or as a measured sound pressure level at a reference distance, either at a single frequency or across all eight octave bands from 63 Hz to 8 kHz. Every field starts blank and no result appears until the checklist is complete and you press Generate result. There is a step by step walkthrough of every field in the noise barrier calculator guide.
Outdoor sound propagation is a subtraction. Start from the source sound power, then subtract each attenuation term in turn to arrive at the level at the receiver.
Geometric divergence comes first. Sound spreading from a point source loses six decibels per doubling of distance, which the standard expresses as twenty times the logarithm of the distance plus eleven decibels for hemispherical radiation over a reflecting plane. If you enter a measured pressure level rather than a sound power, the tool inverts this term to recover the power first.
Atmospheric absorption follows, and it is strongly frequency dependent. The coefficient is computed from ISO 9613-1 using temperature and relative humidity, through the oxygen and nitrogen molecular relaxation frequencies and the classical term. At 63 Hz it is negligible over any practical distance. At 8 kHz it can dominate everything else, which is why a distant road sounds like a rumble rather than a hiss.
Ground effect comes next. The tool uses the alternative method from ISO 9613-2, built from the mean propagation height above the ground and the source to receiver distance, then interpolates between porous and hard ground using the ground factor you set. Soft ground absorbs; hard ground reflects and can raise the level above free-field.
Barrier attenuation is the term the tool exists for. A barrier only works if it breaks the line of sight between source and receiver, and the tool tests that geometrically before applying anything. Where it does break it, the path length difference between going over the top and going straight through is what determines the screening. That difference, divided by the wavelength and scaled, gives the diffraction term, capped at 20 decibels for a single edge and 25 for a double edge, because measurement does not support more.
Two refinements matter. Double diffraction over two edges or across the width of a building gets a correction based on the separation between the edges relative to the wavelength. And a meteorological correction reduces the screening at long range, because downwind refraction bends sound over the top of a barrier that would otherwise shield.
One detail is easy to get wrong, and the tool follows the standard on it: when a barrier screens the path, the ground attenuation term is set to zero rather than being added to the barrier term. The barrier already accounts for the ground effect it destroys. Adding both double-counts, and on soft ground that error flatters the barrier by several decibels.
The source level can be a sound power level or a measured pressure level with its reference distance, and either a single frequency or eight octave bands. Band mode is the honest choice for a real source, because barrier performance and atmospheric absorption both change so much across the spectrum that a single-frequency answer can mislead in either direction.
Source to receiver distance, source height and receiver height set the geometry. Receiver height matters more than people expect: the same barrier that shields a ground-floor window may do almost nothing for a second-floor bedroom, because the line of sight clears the top.
Barrier position and height are the design variables. Position matters as much as height, and the tool makes the reason visible: a barrier close to the source or close to the receiver forces a longer detour than the same barrier in the middle of the gap. The double configuration adds a second barrier, and the building configuration models a thick obstacle by placing two edges a wall thickness apart.
Ground factor, temperature and relative humidity set the propagation conditions. The zone selector sets the limit the result is judged against, and the method toggle switches the diffraction formulation.
The verdict compares the predicted level against the baku tingkat kebisingan for the land-use zone selected. The eight zones and their limits are the ones in the Indonesian environmental noise regulation: housing and settlement at 55 dB(A), trade and services at 70, offices and commerce at 65, green open space at 50, industry at 70, government and public facilities at 60, recreation at 70, and hospitals, schools and places of worship at 55.
In octave band mode the tool A-weights each band, sums them energetically, and compares the resulting A-weighted level. In single-frequency mode it reports the level at that frequency and shows the A-weighted equivalent alongside, so that the comparison against a dB(A) limit is explicit rather than implied.
The insertion loss figure is usually the more useful number in a design conversation. It is the difference between the level with the barrier and the level without it, and it is what a client is actually buying. A barrier that brings a receiver from 61 to 45 dB(A) has earned its cost; one that delivers two decibels has not.
Load the example and the tool fills an eight-band source, a 30 metre source to receiver distance, a source 1.2 m and a receiver 1.5 m above ground, a single 4 m barrier 5 m from the source, mixed ground, 30 degrees Celsius and 80 percent relative humidity, judged against the housing zone limit.
Generate the result and you get the total level with its unit, the level without the barrier, the insertion loss, a running attenuation breakdown term by term, a full per-band table showing sound power, divergence, atmospheric absorption, ground, barrier, and the resulting pressure and A-weighted level for each band, and the geometry actually used including the path length difference.
The per-band table is where the design insight lives. Barriers are poor at low frequency because the wavelength is long relative to the path difference, so a barrier that handles a 1 kHz tyre hiss well may leave a 63 Hz engine rumble almost untouched.
This is one source, one receiver, one path, over flat ground. A real road is a line source, a real site has several sources at once, and both change the answer. Reflections off a facade opposite, off a parallel barrier, or off hard ground between obstacles are not modelled, and a reflective barrier facing a building across a street can make things worse rather than better.
Terrain is flat by assumption. A berm, a cutting, a slope or a change in level all alter the geometry and can outperform a wall for the same cost. Barrier transmission is not modelled either: the calculation assumes the barrier is heavy enough that sound diffracting over the top dominates sound passing through it, which requires a real surface mass and no gaps. A barrier with an open joint at the base can lose most of its performance.
The ground effect uses the standard's simplified alternative method, which is derived for broadband A-weighted assessment and is applied here per band as an approximation. And the meteorological correction represents one downwind condition, not a statistical year.
Treat the output as early-design sizing, the right tool for deciding roughly how tall a barrier needs to be and where to put it. A regulatory submission needs a full environmental noise assessment with measured source data, multiple sources, terrain and reflections.
This calculator sits alongside the other acoustic tools in the design calculators set. The RT60 calculator covers reverberation inside the rooms this barrier is protecting, and the room mode calculator covers the low-frequency behaviour of those rooms.
For the reference documents behind the numbers, see the standards library, and for the vocabulary, the terminology reference.
Environmental noise work is part of ALTA Integra's acoustic consultant practice. If you need a full assessment with multiple sources, reflections, terrain modelling, noise mapping or compliance reporting, talk to the team.
Cookies keep this site working. Analytics show us which pages are useful so we can improve them, and they stay off unless you allow them. We run no advertising here and we do not sell your data. Cookie Policy.
Choose which cookies this site can use. You can change this at any time from the Cookie settings link in the footer.
These cookies are required for the site to work and cannot be turned off. Our hosting provider also runs its own visitor measurement on every page. It is set by the host, not by us, and this site cannot switch it off.
These cookies help us understand how visitors use the site so we can improve it. They stay off until you turn them on.