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Calcimator

Certificate Validity Calculator

Calculate certificate security level, validity period recommendations, and certificate strength analysis.

Inputs

bits
days

Results

Overall Security Level

128 bits

Recommended Renewal Period

365 days

Certificate Security1,024 bits
Hash Collision Resistance128 bits
Expiration Risk10 / 100
How to Use This Calculator
  1. Enter the certificate issue date and expiration date.
  2. Set the current date to calculate remaining validity.
  3. Review days remaining and whether the certificate is within its renewal window.
  4. Flag certificates expiring within 30 days for immediate renewal action.
  5. Use the output to maintain a certificate inventory and automate renewal reminders.

What each input means

Certificate Key Length
RSA certificate key length
Validity Period
Certificate validity period
Hash Algorithm
Hash algorithm used in certificate

How this is calculated

Formula

Security Level = min(Certificate Security, Hash Collision Resistance)

Worked example, using the default values

  1. Identify Input Parameters
    Certificate Key Length = 2048, Validity Period = 365, Hash Algorithm = 0 = 3 input(s) provided
  2. Calculate Overall Security Level
    Overall Security Level
    128 = 128
  3. Calculate Recommended Renewal Period
    Recommended Renewal Period
    365 = 365
  4. Calculate Certificate Security
    Certificate Security
    1024 = 1024
  5. Calculate Hash Collision Resistance
    Hash Collision Resistance
    128 = 128

Engine last updated . Checked against 3 independently-derived tests — how we verify calculators.

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