How do you calculate installed base coverage?

Divide covered installed units by your active installed base and multiply by 100. With 3,850 covered units out of 5,200 active, coverage is 74.0%.

What is a good installed base coverage rate?

Mature aftermarket programs often run 70-85%; best-in-class OEMs push past 85%. At 74.0% against an 80% target you have a 6.0-point gap to close, which is realistic within a renewal cycle.

What's the difference between installed base coverage and attach rate?

Attach rate measures how many new units ship with a contract at point of sale; coverage measures the whole live fleet, including renewals and lapses, so it's the running total attach rate feeds into.

Why is my installed base coverage gap negative or positive?

The gap is coverage minus target. A positive 6.0-point gap here means you're below target by that amount; once coverage exceeds target the figure flips and you're running ahead.

How do I improve installed base coverage?

Prioritize uncovered units nearing warranty expiry, win back lapsed contracts, and raise new-machine attach. Here, 1,350 uncovered units (5,200 minus 3,850) are the addressable pool.

Does retiring old equipment change coverage?

Yes. Removing dead units from the active installed base shrinks the denominator and can lift coverage even with no new contracts sold, so keep your fleet records current.

Aftermarket, Field Service & Service Parts calculator

Installed Base Coverage Calculator

Installed base coverage tells you what share of the equipment you've shipped is still wrapped in a service contract, extended warranty, or active maintenance agreement. Aftermarket and field-service leaders watch it because every uncovered unit in the field is recurring revenue you're leaving on the table and a customer who may defect to a third-party servicer. It's the single best leading indicator of attach-rate health and renewal momentum across a product fleet. A rising coverage number means your renewals and new-machine attach are outpacing fleet retirements; a falling one signals churn you need to chase before warranties lapse.

What this calculator does

Calculate the share of installed equipment covered by active service contracts, dealer support, or planned maintenance programs.
an aftermarket sales or service operations manager needs to measure coverage of the active installed base
It computes the percentage of your active installed base that currently sits under a service or warranty agreement, plus how many percentage points you are from your coverage target.

Formula used

Installed base coverage = covered installed units ÷ active installed base × 100
Coverage gap to target = installed base coverage - target coverage

Inputs explained

Covered installed units (under contract or warranty):
Active installed base in the field:
Target installed-base coverage:

How to use the result

Use it in quarterly aftermarket reviews, before setting renewal-campaign goals, and when sizing the uncovered fleet your sales team should target.
It treats every covered unit as equal value, so a fleet skewed toward low-margin or near-retirement machines can look healthier than the revenue actually justifies.

Common questions

How do you calculate installed base coverage? Divide covered installed units by your active installed base and multiply by 100. With 3,850 covered units out of 5,200 active, coverage is 74.0%.
What is a good installed base coverage rate? Mature aftermarket programs often run 70-85%; best-in-class OEMs push past 85%. At 74.0% against an 80% target you have a 6.0-point gap to close, which is realistic within a renewal cycle.
What's the difference between installed base coverage and attach rate? Attach rate measures how many new units ship with a contract at point of sale; coverage measures the whole live fleet, including renewals and lapses, so it's the running total attach rate feeds into.
Why is my installed base coverage gap negative or positive? The gap is coverage minus target. A positive 6.0-point gap here means you're below target by that amount; once coverage exceeds target the figure flips and you're running ahead.
How do I improve installed base coverage? Prioritize uncovered units nearing warranty expiry, win back lapsed contracts, and raise new-machine attach. Here, 1,350 uncovered units (5,200 minus 3,850) are the addressable pool.

Last reviewed 2026-05-12.