Content decay is the slow, quiet loss of organic traffic to a page that used to perform well. It rarely arrives as a crash. It arrives as a page that made 2,800 sessions two years ago, 1,900 last year, and 1,150 this month, with nobody noticing because the site total stayed flat while newer articles picked up the slack. This content decay calculator puts a rate on that decline and tells you whether a refresh pays for itself.
Arb Digital's content team audits for decay every quarter, because on any site with more than a couple of years of publishing history, updating existing pages usually returns more per hour than writing new ones. The pages are already indexed, already linked, and already have ranking history. They just stopped being the best answer.
What This Content Decay Calculator Does
Enter the page's peak monthly sessions, its current monthly sessions, and how many months have passed since that peak. The calculator derives a compound monthly decay rate — the steady percentage decline that would have produced the drop you actually observed — rather than dividing the loss evenly across the period, which understates how fast a decline is accelerating.
It then converts the decline into money using your value per session, projects where the page lands in three, six, and twelve months if nothing changes, and scores refresh priority from 0 to 100 by weighing the size of the decline against the return on your refresh cost. The projection bars are the part most people find persuasive: watching a page trend toward a few hundred sessions makes the case for an afternoon of editing far better than a percentage does.
How to Use It
- Find the page's peak month. In the Search Console performance report or your analytics platform, open a two-year view for the single URL and take the best full month. Avoid partial months and avoid one-off spikes caused by a newsletter or a social post.
- Enter current monthly sessions. Use the last complete month, or an average of the last three if traffic is noisy.
- Enter months since peak. Count from the peak month to the current one.
- Set value per session. Divide the revenue or pipeline attributable to organic traffic by total organic sessions. If you have no figure, use the cost of buying an equivalent click.
- Enter your refresh cost and recovery assumption. Cost is writer time plus review time. Recovery is the share of lost traffic you expect back — start conservative and revise once you have refreshed a few pages and measured the result.
The Formula: How Decay Is Calculated
Decay is modelled as compound decline, the same arithmetic as compound interest running backwards:
Monthly decay rate = 1 − (Current ÷ Peak)1 ÷ Months
A page falling from 2,800 to 1,150 sessions over 14 months gives 1 − (1150 ÷ 2800)1/14 = 1 − 0.9385 = 6.15% per month. That compounding is what makes decay dangerous: a 6% monthly rate removes just over half the remaining traffic every eleven months, so a page that looks merely soft this quarter can be negligible by next year.
Refresh priority combines the scale of the decline with the return on fixing it:
Priority = min(100, Decline% × 0.5 + min(50, (Annual recoverable value ÷ Refresh cost) × 10))
In the example above, the decline is 58.9%, contributing 29.5 points. Recoverable traffic is 1,650 lost sessions × 60% = 990 sessions a month, worth $1,188 monthly and $14,256 a year against a $400 refresh — a ratio far past the cap, contributing the full 50 points. Total: 79 out of 100, which lands in the refresh-now band.
Not Every Decline Is Decay
Before treating a number from this tool as a mandate, rule out three impostors. Seasonality is the most common: a page about tax deadlines or summer holidays will fall 80% out of season and recover without anyone touching it. Compare the same month across two years rather than this month against a peak.
Query deprecation is the second. If the topic itself is being searched less — a discontinued product, a superseded software version, a fading trend — the page is not losing share, the market is shrinking. No refresh recovers demand that no longer exists, and the correct response is usually to redirect or repurpose rather than rewrite.
Results-page changes are the third. If a feature now answers the query directly above the organic results, your position may be unchanged while clicks fall. Search Console makes this visible: flat impressions with falling clicks points at the results page, while falling impressions points at rankings. Modelling how much a feature absorbs is exactly what the SERP feature opportunity calculator is for.
The Three Real Causes, and What Each Needs
Staleness. The page contains dates, statistics, screenshots, or product details that are now wrong. Readers bounce, competitors publish current versions, and rankings follow. The fix is genuine updating — new data, new examples, removed obsolete sections — not changing the published date. Search engines have consistently indicated that superficial freshness signals without substantive change do not help, and Google's guidance around core updates points firmly at overall content quality rather than recency markers.
Competitive displacement. Somebody published something better. Your page has not changed at all; the bar has. The fix requires reading the pages now outranking you and closing the specific gaps — depth, structure, examples, media — rather than adding words for their own sake.
Intent drift. The dominant meaning of the query changed. A term that used to return tutorials now returns product comparisons because that is what searchers wanted. This is the hardest case, because the fix is a different page rather than a better version of the existing one.
Why Refreshing Usually Beats Publishing
A refresh starts from a page that is already indexed, already carries internal and external links, and already has measurable ranking history for known queries. A new article starts from zero on all four counts. When the decayed page still holds respectable positions, the distance from position 8 to position 3 is a much shorter trip than the distance from unranked to position 8.
That is why the payback figure matters more than the decline percentage. A page decaying 10% a month but worth $30 a month is not worth a $400 refresh, no matter how alarming the rate looks. A page decaying 2% a month but worth $4,000 a month is the most urgent thing on your list. The priority score exists to keep those two straight, and pairing it with the content ROI calculator gives a fuller picture of what each hour of editorial time returns.
When to Leave a Page Alone
Some decay should simply be accepted. Pages tied to an event that has passed, a version that is no longer supported, or a trend that has ended are not recoverable and consume review time every quarter they stay on the list. Consolidating them into a broader evergreen page, or redirecting them to the closest genuinely relevant destination, removes them from the audit permanently.
Equally, resist refreshing a page whose decline began the week a competing page on your own site was published. That is not decay, it is cannibalization, and rewriting either page makes it worse. Run the URLs through the keyword cannibalization checker first; if two of your pages are trading positions for the same query, merging them is the fix.
Building a Decay Review Cycle
The audit that works is quarterly and short. Export every URL with its sessions for the last complete month and for the same month a year earlier. Sort by absolute session loss rather than percentage, because percentage flatters tiny pages and hides the ten large ones doing the real damage. Run the top twenty through this calculator, refresh anything scoring above 75, and diarise the rest.
Measure the outcome. Note each refreshed page's sessions before the edit and eight to twelve weeks after, and use those results to correct your recovery assumption. Teams that do this typically discover their real recovery rate is either far better or far worse than the 60% default, and either answer makes every future prioritisation more accurate.
Arb Digital's content team audits decaying pages, rewrites the ones worth saving, and consolidates the ones that are not — so editorial time goes where it earns the most.
Content Marketing SEO ServicesCommon Mistakes to Avoid
- Comparing this month to a seasonal peak — always check the same month a year earlier before declaring decay.
- Changing the published date without changing the content — a date is not an update and readers notice immediately.
- Sorting the audit by percentage decline, which promotes tiny pages above the large ones losing real traffic.
- Refreshing a page that is being cannibalized by another of your own pages, which deepens the conflict instead of fixing it.
- Never measuring the outcome, leaving your recovery assumption permanently unvalidated.
Related Free Tools From Arb Digital
Confirm the decline is not a self-inflicted conflict with the keyword cannibalization checker, check whether the refreshed page will be substantial enough using the SEO content length checker, and rewrite the listing that earns the click with the SERP snippet preview. Model what recovery is worth using the SEO traffic forecast calculator, and check editorial returns with the content ROI calculator. More in the free online tools hub.
Frequently Asked Questions
It is the gradual loss of organic traffic to a page that previously performed well, usually caused by the content becoming outdated, competitors publishing better material, or the meaning of the query shifting over time.
It is a compound rate: one minus the ratio of current to peak traffic, raised to the power of one divided by the number of months. That reflects steady percentage decline rather than an even split of the total loss.
No. A page losing traffic it never monetised may not justify the editorial cost, while a slowly declining high-value page can be the most urgent item on the list. The priority score weighs decline against the return on your refresh cost for that reason.
Compare the same calendar month across two years instead of comparing the current month to an all-time peak. Genuine decay shows a lower figure year over year; seasonality shows a repeating annual shape.
Not on its own. Freshness signals without substantive changes to the content do not address why the page lost rankings, and readers quickly notice a new date on unchanged material.
It varies far too widely to promise a figure, which is why recovery is an input rather than a constant here. Track the results of your own refreshes and replace the default with your measured average.
Quarterly suits most publishing schedules. Sort by absolute sessions lost rather than percentage, run the largest losses through this tool, and act on the highest priority scores first.
All figures here are planning estimates based on the numbers you enter — traffic recovery after a content refresh varies by site, topic, and competition and is never guaranteed.
