How to use this calculator
- Enter or choose deliveries counted.
- Enter or choose deliveries on time.
- Enter or choose target.
- The on-time delivery updates as you type. Use Copy result or Share to keep it.
Method
OTD % = On time ÷ Total × 100; Needed = smallest whole n with (On time + n) ÷ (Total + n) ≥ Target, i.e. n ≥ (Target × Total − On time) ÷ (1 − Target)
- On time
- deliveries within the promised date or window
- Total
- all deliveries in scope
- Target
- as a fraction, e.g. 0.97
Worked example
- OTD = 950 ÷ 1,000 = 95%, with 50 late.
- To reach 97%: n ≥ (0.97 × 1,000 − 950) ÷ 0.03 = 666.7, so 667.
- Check: 1,617 ÷ 1,667 = 97.0%.
On-time delivery is 95%, 2 points below target; 667 consecutive on-time deliveries would bring it to 97%.
What the result means
The “needed” figure shows how slowly a cumulative rate recovers: fixing the cause of late deliveries matters more than waiting for the average to improve.
Assumptions and limits
- “On time” follows one consistent definition (date, time window or appointment).
- It does not weight deliveries by value or volume, and it does not measure completeness (OTIF needs both on time and in full).
Questions
What is the difference between OTD and OTIF?
OTIF counts a delivery only when it is both on time and complete. Enter on-time-and-in-full deliveries as “on time” to get OTIF.
Do early deliveries count as on time?
That depends on your agreement. Many retailers treat early arrivals outside the window as failures.