Time Decay Attribution Calculator
Calculate how conversion credit is distributed across touchpoints using the Time Decay model. This professional-grade tool helps marketers understand the value of touchpoints closer to the purchase decision, optimizing short-cycle marketing spends and mid-funnel engagement.
Calculate fractional revenue credit based on recency to conversion.
Quick Summary
"The Time Decay Attribution model assigns more credit to touchpoints that occur closer in time to the conversion. It follows an exponential decay function, typically with a 7-day half-life, ensuring that the 'closing' interactions receive the highest valuation."
How to Use
- 1Enter the 'Days Since Touchpoint' for each interaction in your customer journey (e.g., 0 for today, 7 for a week ago).
- 2Set the 'Half-Life' period (standard industry default is 7 days).
- 3Enter the 'Total Conversion Value' to see how the revenue is distributed fractionally.
- 4The calculator will instantly generate the percentage and dollar credit for each touchpoint.
- 5Review the Expert Guide below to learn how to adjust your media mix based on these decayed values.
Understanding Inputs
- Days Since Touchpoint:
The number of days that elapsed between this specific interaction and the final conversion event.
- Half-Life (Days):
The time it takes for a touchpoint's credit to be reduced by half. A 7-day half-life means a click today is worth 2x a click from 7 days ago.
- Conversion Value:
The total revenue or goal value generated by the final conversion.
Example Calculations
Touchpoint at Day 0 (Today), Day 3, and Day 10. Day 0 gets 1.0 weight, Day 3 gets ~0.74, Day 10 gets ~0.37. Normalized to 100%. = 44.4% for Last Touch
Formula Used
Weight = 2^(-Days / Half-Life)Each touchpoint is assigned a weight based on its distance from conversion. These weights are then summed and normalized so their total equals 100% of the conversion credit.
Who Should Use This?
- E-commerce brands with 7-14 day sales cycles.
- SaaS marketers tracking trial-to-paid conversion windows.
- Performance agencies moving away from simplistic 'Last-Click' reporting.
- CMOs looking to justify 'Middle of Funnel' (MOFU) ad spend.
- B2C Lead Gen firms where the 'follow-up' call is the primary closer.
- Retailers running short-term seasonal promotions (e.g., Black Friday).
Edge Cases
If all touchpoints happen on the same day, Time Decay effectively becomes a Linear model (all get equal credit).
Time Decay can heavily penalize 'Top of Funnel' ads from 30+ days ago, potentially leading to under-investment in brand awareness.
The Do's
- • Use Time Decay for products with a clear 'momentum' phase leading to purchase.
- • Adjust your half-life based on your actual 'Average Time to Convert' data.
- • Combine this data with 'First Click' to see if you're neglecting your openers.
- • Test different half-lives (e.g., 2 days for flash sales, 14 for luxury goods).
The Don'ts
- • Don't use Time Decay for long-cycle B2B (6+ months) as it will zero-out your most important early leads.
- • Don't ignore the 'Normalization' error; ensure your sum of parts always equals 1.0.
- • Don't apply this model to 'View-Through' conversions without a significant weight discount.
- • Don't make budget decisions based on a single model; always use multi-model comparison.
Advanced Tips & Insights
The Half-Life Calibration: A VP of Marketing should set the half-life to match the Median Time to Conversion. If your median is 10 days, a 7-day half-life is too aggressive; move it to 10 to avoid over-weighting the very last second.
Incremental Lift Analysis: Use Time Decay to identify 'Channel Cannibalization.' If a channel only appears at Day 0 and carries 90% credit, it might just be capturing existing demand rather than creating it.
Seasonality Adjustments: During peak holidays, the sales cycle compresses. You should shorten your half-life during these periods to reflect the heightened urgency of consumer behavior.
The 'Brand Halo' Effect: Even when early touchpoints are decayed to 5% credit, analyze their volume. High volume low-credit touchpoints often signal a healthy brand discovery engine that feeds the high-credit closers.
Custom Weighted Decay: For advanced stacks, consider 'Asymmetric Decay' where different channels (like Video vs. Search) have different decay curves based on their historical impact.
The Complete Guide to Time Decay Attribution Calculator
Introduction to Time Decay Attribution
In the evolving landscape of digital marketing, the journey from "stranger" to "customer" is rarely a straight line. It is a complex web of interactions across devices, platforms, and time. For years, the industry relied on Last-Click Attribution, a simplistic model that gave 100% of the credit to the final touchpoint. This was the equivalent of giving a basketball player credit for a winning shot while ignoring the player who stole the ball and the player who gave the assist.
Time Decay Attribution is the sophisticated response to this oversimplification. Built on the principle of exponential decay, this model acknowledges that while every touchpoint matters, those occurring closer to the point of purchase are inherently more influential in the final decision-making process. By utilizing a mathematical "half-life," this model provides a scientific way to distribute revenue across the marketing funnel.
The Mathematical Foundation of Decay
The core of this calculator is the exponential decay function: Credit = 2^(-t / h), where t is the time since the interaction and h is the half-life. This ensures that the value of an ad click doesn't just "drop off a cliff" after a certain number of days, but rather fades elegantly. This mirrors the psychological reality of brand recall and purchase intent—the memory of a commercial you saw 20 minutes ago is significantly more potent than one you saw three weeks ago.
Marketers choose this model because it rewards "CLOSERS"—those high-intent search terms and retargeting ads—while still maintaining a fractional pipeline to the "OPENERS." It represents a middle ground between the aggressive conservatism of Last-Click and the egalitarian (and often unrealistic) nature of Linear attribution.
Attribution Model Comparison
To understand where Time Decay fits in your strategy, compare it against the other industry-standard models:
| Model Name | Primary Logic | Best Use Case | Marketing Bias |
|---|---|---|---|
| First Click | 100% credit to the 1st touch | Aggressive Awareness / Branding | Biased toward Top-of-Funnel |
| Last Click | 100% credit to the last touch | Direct Response / Low Margin | Biased toward Retargeting/Brand Search |
| Linear | Equal credit to all touches | Long B2B Cycle / High Consideration | Neutral (No Bias) |
| Time Decay | Exponential credit over time | Standard E-commerce / Retail | Biased toward Bottom-of-Funnel |
| Position-Based | 40% First, 40% Last, 20% Mid | Balanced Growth Platforms | Biased toward Openers & Closers |
Industry Benchmarks: Half-Life Recommendations
Choosing the correct half-life is the difference between accurate reporting and misleading data. Here are the recommended ranges based on vertical and sales cycle intensity:
| Industry / Vertical | Sales Cycle Speed | Recommended Half-Life | Rational |
|---|---|---|---|
| FMCG / Impulse Buy | 0 - 2 Days | 1 - 2 Days | Decisions are made instantly; memory fades rapidly. |
| General E-commerce | 7 - 14 Days | 7 Days | The 'Industry Standard' for a typical weekly pay cycle. |
| SaaS / Subscription | 14 - 30 Days | 14 Days | Accounts for the free-trial and evaluation phase. |
| High-Ticket / Luxury | 30 - 90 Days | 28 Days | Ensures month-old leads still carry meaningful weight. |
Step-by-Step Optimization Workflow
Once you have your Time Decay data, use this 5-step workflow to maximize your marketing efficiency:
- Identify the 'Closer' Channels
Filter your results to find channels that consistently have over 40% credit share. These are your 'Execution' channels. Maximize their budget until you see diminishing marginal returns (hitting your CPA ceiling).
- Isolate the 'Assist' Leaders
Look for channels with low individual credit (5-10%) but high volume. These are your assists. If you cut these because they look 'inefficient,' your 'Closer' channels will often see a 20-30% drop in volume within weeks.
- Calculate Decay-Adjusted ROAS
Divide the fractional revenue attributed by the Time Decay model by the actual spend for that channel. This 'Real ROAS' is far more accurate for month-over-month planning than the platform-reported Last-Click ROAS.
- Optimize Half-Life Monthly
Review your 'Time to Purchase' report. If your sales cycle is lengthening due to economic factors, increase your half-life. If you're running a heavy promotion, shorten it.
- Redistribute 'Wasted' Awareness Spend
If top-of-funnel channels are getting less than 1% credit even in a generous 14-day half-life model, they are likely not reaching the right audience. Pivot that budget to your 'Assist' leaders found in Step 2.
Advanced VP-Level Strategies
For marketing leaders managing 7 or 8-figure budgets, Time Decay is just the beginning. Implement these high-level strategies:
1. Counter-Cyclical Budgeting
During periods of low competition (high CPC efficiency), Time Decay will show that early touchpoints are extremely cheap per assist. Front-load your branding budget when competitors are quiet, even if the 'decayed' revenue doesn't show up for 3 weeks.
2. The 'Frequency vs Decay' Pivot
If your frequency is high (over 6.0) but your Time Decay credit is low, you are 'over-serving' an audience that is not converting. Immediately shift that frequency to a newer audience to widen the top of your funnel before the closing phase.
Interpreting Your Results: 4 Key Scenarios
Scenario A: Under-performing (Credit Concentration)
95% of credit goes to the final touch. This is a fragile 'Parasitic' campaign strategy. You are likely bidding too high on your own brand name and not doing enough to reach new people.
Scenario B: Stable (Smooth Decay Curve)
Credit is evenly tiered (e.g., 50%, 30%, 15%, 5%). This indicates a healthy, repeatable funnel. Maintain current budget allocations and focus on creative testing.
Scenario C: High-performing (Long Tail Value)
Touchpoints from 15+ days ago are still carrying 10-15% credit despite decay. This is a 'Brand Powerhouse.' You have successfully built long-term recall; scale your awareness budget.
Scenario D: Scaling (High Velocity)
The Window of Influence is compact (under 3 days). This is the 'Blitzscale' phase. Pour money into whatever gets the click, as the consumer is in a 'Buy Now' frenzy.
Conclusion
Time Decay is the most honest rules-based attribution model for modern commerce. It respects the closer without disrespecting the architect. By mastering this calculator and the strategies in this guide, you move beyond 'guessing' your ROI and toward a data-driven media mix that can withstand market fluctuations and competitive pressure.
Summary & Key Takeaways
- ★Time Decay rewards touchpoints occurring closer to the conversion event.
- ★The 7-day half-life is the standard but should be adjusted based on your median sales cycle.
- ★Use this model to identify 'assist' channels that would be undervalued by Last-Click.
- ★Decay-Adjusted ROAS is the most accurate benchmark for monthly budget planning.
- ★Avoid the trap of 'Demand Exhaustion' by keeping a healthy mix of low-credit awareness ads.