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Age Standardised Rate Calculator

Work out age standardised rate instantly with clear inputs, formula shown and shareable results.

About Age Standardised Rate Calculator

Applies direct standardisation across two age strata: the stratum-specific rates are weighted by the standard population structure rather than the local one.

Formula

Direct standardisation

ASR = sum of (stratum rate x standard population weight); the crude rate uses the local weights instead

Worked example

With the default values below, Age Standardised Rate Calculator returns Age-standardised rate of 6.500. Change any input above and every figure here is recalculated in your browser.

Inputs used

Rate in the younger stratumaccepts 0–1,000 per 1000
2 per 1000
Rate in the older stratumaccepts 0–1,000 per 1000
20 per 1000
Older share of the standard populationaccepts 1–90
25
Older share of the local populationaccepts 1–90
40

Results

Age-standardised rate
6.500 per 1000
Crude rate in the local population
9.200 per 1000
Crude to standardised ratio
1.415
Difference attributable to age structure
2.700 per 1000

Step by step

  1. 1Values used
  2. 2Direct standardisation
  3. 3Age-standardised rate= 6.500 per 1000
  4. 4Crude rate in the local population= 9.200 per 1000
  5. 5Crude to standardised ratio= 1.415
  6. 6Difference attributable to age structure= 2.700 per 1000

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Which standard population is used?

The WHO World Standard, European Standard or a national reference; rates are only comparable if the same standard is used.

Why two strata here?

It demonstrates the arithmetic transparently; a full analysis uses five-year age bands with the same weighted-sum method.

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