Make a Spectrogram Online

What you get here

Open an audio file, a video or your microphone at the top of this page, and the sound becomes a spectrogram: all of it, laid out as one picture. There is nothing to install, and nothing is uploaded.

The picture is yours to work with. Zoom in on any moment of a recording, or any range of pitch, and the spectrogram is redrawn from the audio rather than stretched, so the detail stays sharp. When it shows what you need, save it as a PNG. The scales and the file name are printed on it, so anyone you send it to can tell what they are looking at.

What a spectrogram shows you

Time runs from left to right, and pitch, or frequency, rises from the bottom to the top. Brightness is loudness: the brighter a spot, the louder that part of the sound. What the shapes in the picture mean is a subject of its own, covered in our guide on how to read a spectrogram.

Making a spectrogram from a file or a microphone

To see a recording, drag the file onto the box at the top of this page, or click the box to choose it. MP3, WAV, M4A and FLAC all work, and so does a video, such as an MP4 or MOV from your phone: the spectrogram is drawn from its sound.

Your browser decodes the file on your own device. It is never uploaded, so a private recording stays private.

To watch sound as it happens, press Open your microphone and allow it when the browser asks. The spectrogram then scrolls as you talk, sing or play, with the newest sound at the right.

No recording to try? Click one of the three examples under the box: birdsong, a sung note or a noisy recording.

Saving the picture

The spectrogram on screen is gone when you close the tab. To keep it:

1. Frame the part you want. Scroll on the picture to zoom in on time, scroll on the Hz scale to zoom in on pitch, and drag to move around. On a phone, pinch and drag.
2. Press Export PNG. It is in the row of controls under the picture.
3. Find the file in your downloads. It is named after your recording, like interview-spectrogram.png.

The PNG shows exactly the part you framed, in the colors on your screen. It is drawn again from the audio at about 2,000 pixels wide, not copied from the screen. The frequency and time scales are printed along its edges, with the file name and the settings underneath and hertzspot.com in one corner.

A saved spectrogram goes wherever a picture can: into your notes, a lab report or homework, a slide, or a message to a colleague, so they see what you heard.

To compare two recordings, export each one and put the two pictures side by side. The line under each picture lists its time and pitch range and its settings, so you can check that the two match.

With the microphone, export before you press Stop microphone, because stopping clears the picture. And for a bare picture with no numbers on it, uncheck Show labels and take a screenshot instead.

Spectrogram generator, viewer, or analyzer

Search for a spectrogram online and you will find tools under all three names. They draw the same kind of picture. What differs is what you want from it.

A viewer is for looking: you open a sound and see it as a spectrogram. A generator is for keeping: the point is the picture itself, saved as a file. A spectrogram analyzer is for measuring: it reads values off the picture, such as the exact frequency of a line or how loud it is.

This page does the first two. You make the spectrogram, look through it, and save it. Those readings are here too if you want them, because this is the same tool as our audio spectrum analyzer, the page built around them.

Questions