Free · Cardiovascular system calculators ❤️

Heart Rate from ECG Paper Distance or Boxes

Use the actual paper speed, which may be 25 or 50 mm/s.

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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Use the result with context

Health results are educational estimates, not a diagnosis or treatment recommendation. A qualified clinician can interpret measurements in the context of your health.

Formula and method

At 25 mm/s, an R–R distance of 20 mm takes 0.8 seconds and gives 75 beats/minute.

Heart rate = 60 × paper speed (mm/s) / R–R distance (mm). Each small box is 1 mm and each large box is 5 mm.

Worked example

Enter these known values and leave the other values blank.

R–R paper distance
20 mm
Boxes between R waves
20
Heart rate (beats/minute)
75

Assumptions and limitations

  • Use the actual paper speed, which may be 25 or 50 mm/s. The interval method estimates rate for the measured beat pair; it does not classify rhythm or reliably summarize an irregular rhythm from one interval. Fractional box counts are valid measurements.
  • Clear an unknown control before solving the supported arithmetic relationship.
  • This model does not select medical treatment or establish a diagnosis.

Common questions

How is the result calculated?

Heart rate = 60 × paper speed (mm/s) / R–R distance (mm). Each small box is 1 mm and each large box is 5 mm.

When does this model apply?

Use the actual paper speed, which may be 25 or 50 mm/s. The interval method estimates rate for the measured beat pair; it does not classify rhythm or reliably summarize an irregular rhythm from one interval. Fractional box counts are valid measurements.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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