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Approval lead time: the change is one delay, the answer another

A change proposal already carries its own schedule effect. Type what the changed work waits on, each with its lead time and the date it is needed by, and every chain is walked back to the last date an approval can arrive without adding a day, with the item whose chain runs out first named beside it. Past that date only the days the wait added are counted, on their own line and never folded into the 11 days the change was already worth.

Live result

Approval on 2026-04-14 adds 4 waiting days beyond the last safe date.
  • last safe approval date2026-04-10
  • change days held separately11 days
The binding item is the one whose availability sets that date, and the two day counts never add.
Approval on 2026-04-14 adds 4 waiting days beyond the last safe date.The binding item is the one whose availability sets that date, and the two day counts never add.

All dependencies describe the same affected scope and information state, and every typed lead starts only after approval. Separate scopes, revisions, or approval states need separate records.

Try a scenario

Approval date and the deferral it moves

Move only this civil date. Every dependency, lead, required date, named opening, and the change effect stays fixed.

Last safe approval
2026-04-10
Added waiting days
4 days
Added deferral by approval dateAdded deferral stays at zero through 2026-04-10. At the selected approval date it is 4 whole days.Added deferral, days0265104-0105-31Approval datelast safetyped date04-14 · 4

The rail checks every civil day in its shown range. Continuous dependencies rise one day at a time. Named openings jump by the distances between the dates you entered.

The typed change record

days

Dependencies

Dependency 1

Availability

days

Dependency 2

Availability

days

Dependency 3

Availability

days

Dependency 4

Availability

days

Dependency 5

Availability

days

Comma separated ISO dates in increasing order. The planned opening is first.

Tracked answer

Last safe approval
2026-04-10
Binding dependency
Design release
Added waiting days
4 days
Change effect days
11 days, held separately

The two day counts are not added.

Design release
Last safe approval2026-04-10Ready on2026-04-21Added days4 days
Order amendment
Last safe approval2026-04-15Ready on2026-04-19Added days0 days
Vendor queue
Last safe approval2026-04-16Ready on2026-04-24Added days0 days
Material commitment
Last safe approval2026-04-18Ready on2026-04-20Added days0 days
Work opening
Last safe approval2026-04-29Ready on2026-04-16Added days0 days

It walks the leads and civil dates you typed, keeps change effect separate from approval deferral, and does not price a change, decide entitlement, judge reasonableness, or read an agreement.

Here is the maths

The formula, in words

For continuous availability, subtract the whole lead from the required date. For named openings, subtract the lead from the planned opening. The earliest result is the overall last safe approval date. At the typed approval date, add the lead and compare readiness with the required date or choose the first named opening on or after readiness. The largest dependency deferral is the tracked waiting answer.

S=D−LS=D-L
where SS is the safe date, DD the required or planned date, and LL the lead in days.
W=max⁡idiW=\max_i d_i
where WW is the added deferral in days and did_i the dependency deferral. change effect stays separate

A worked example

  1. Design release is required on 2026-04-17 and needs 7 days after approval, so its last safe approval is 2026-04-10.
  2. Approval on 2026-04-14 makes design release ready on 2026-04-21, which is 4 days after the required date.
  3. The tracked waiting answer is 4 days. The change effect remains 11 days on its own line, and 15 days is not printed.

What this does not model

It does not test scope identity, information changes, logic quality, notice, entitlement, valuation, compensability, or reasonableness. A place or part of the work available on named dates is treated only through those dates, with no invented opening between them.

What the sweep holds fixed

Only approval date moves, one whole civil day at a time. The proposal date, names, leads, required dates, openings, and change effect stay fixed.

Source anchor

U.S. Government Accountability Office, Schedule Assessment Guide. The guide describes schedules through logical relationships, durations, status, and documented changes. This page uses independently authored civil date and maximum arithmetic and reproduces no method wording or table.

Calculation version

1.0.0

The whole record prints. Your browser can save it as a PDF instead of printing it.

This instrument describes typed civil date arithmetic only. It never decides entitlement, prices a change, interprets an agreement, calls a day compensable, or decides whether an approval was reasonable. No named opening is inferred between the dates entered.

Related

Last safe approval record

Approval lead time: the change is one delay, the answer another

Accepted inputs

Proposal date
2026-04-01
Approval date
2026-04-14
Change effect held separately
11 days
Dependency 1
Design release, 7 days, 2026-04-17
Dependency 2
Order amendment, 5 days, 2026-04-20
Dependency 3
Vendor queue, 10 days, 2026-04-26
Dependency 4
Material commitment, 6 days, 2026-04-24
Dependency 5
Work opening, 2 days, 2026-05-01, 2026-05-08, 2026-05-15, 2026-05-22, 2026-05-29, 2026-06-05, 2026-06-12

Tracked answer

Last safe approval
2026-04-10
Binding dependency
Design release
Added waiting days
4 days
Change effect days
11 days, held separately

Record fields

Calculation version
1.0.0
Boundary
It walks the leads and civil dates you typed, keeps change effect separate from approval deferral, and does not price a change, decide entitlement, judge reasonableness, or read an agreement.
Source
U.S. Government Accountability Office, Schedule Assessment Guide

This instrument describes typed civil date arithmetic only. It never decides entitlement, prices a change, interprets an agreement, calls a day compensable, or decides whether an approval was reasonable. No named opening is inferred between the dates entered.

Badr Alghamdi · badralghamdi.com/tools/last-safe-approval