Free Engineering Tool
Scopes and signals
Oscilloscope Screen Reading Calculator
Count the divisions on the screen, enter the knob settings, and get the real period, frequency and voltage of the waveform.
- Free
- No sign-up
- Runs in your browser
- Your numbers never leave your device
Inputs
Horizontal distance between two matching points.
Vertical distance from lowest to highest point.
Choose ×10 or ×100 only if the V/div you read is at the scope input and does not already include the probe.
Readout
The formulas
T = divisions × (time/div) · f = 1 / T · Vpp = divisions × (volts/div) × probe
Vpeak = Vpp / 2 · Vrms = Vpp / (2√2) sine · Vpp / (2√3) triangle · Vpp / 2 square
Count a full cycle between two matching points, such as one rising zero-crossing to the next. Measuring several cycles and dividing gives a more accurate period than reading one.
Getting a good reading
- Fill the screen. Adjust volts/div so the waveform spans at least four to six divisions vertically. A small trace has large reading error.
- Check the coupling. The RMS values assume a waveform centred on zero. A DC offset adds to the true RMS but not to the peak-to-peak value.
- Check the probe. A ×10 probe divides the signal by ten. If your scope does not know the probe setting, multiply the screen value by ten yourself.
- Mind the bandwidth. Near the scope limit the amplitude reads low. Test it with the bandwidth calculator.
New to the controls? Start with how to use an oscilloscope and how to read a waveform.
Ready to specify? We'll respond the same day.
Send your requirement by email or WhatsApp - we respond within one business day.