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Calcimator

Secretary of Interior Standards Calculator

Compliance scoring against SIS treatment standards.

Inputs

Results

Average score (0-10)

7.1

Compliance (%)71
Passes review (0/1)1
HTC eligible (0/1)1
Weakest area score6
How to Use This Calculator
  1. Score Standards 1–5 individually (0–10): Compatible use, Retain character, Physical record, Preserve significant changes, and Preserve distinctive features.
  2. Enter the average score for Standards 6–10 (repair, chemical/physical treatments, new additions, and archaeological resources).
  3. The Average score (0–10) represents overall compliance — scores of 7 or higher generally satisfy NPS and SHPO reviewers.
  4. Check Passes review (1=yes) to gauge whether the project design is likely approvable for federal certification.
  5. Review HTC eligible (1=yes) — projects failing review are ineligible for the 20% federal Historic Tax Credit.
  6. Focus improvement on the Weakest area score — raise the lowest-scoring standard to maximize compliance before submitting plans.

How the result changes with Stds 6-10 avg (0-10)

Stds 6-10 avg (0-10)Average score (0-10)
14.1
3.55.35
6.56.85
98.1

What each input means

Std 1: Compatible use (0-10)
New use compatible with historic character.
Std 2: Retain character (0-10)
Retain historic character.
Std 3: Physical record (0-10)
Recognize property as record of its time.
Std 4: Preserve features (0-10)
Preserve changes that have acquired significance.
Std 5: Distinctive features (0-10)
Preserve distinctive materials, features, spaces.
Stds 6-10 avg (0-10)
Average score for Standards 6-10 (repair, chemical/physical treatments, new additions, etc.).

What each result means

Average score (0-10)
Average compliance score across all 10 standards.
Compliance (%)
Compliance as percentage.
Passes review (0/1)
1 = Likely to pass NPS/SHPO review.
HTC eligible (0/1)
1 = Likely eligible for Historic Tax Credit.
Weakest area score
Lowest scoring standard to focus improvement.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Std 1: Compatible use (0-10) = 7, Std 2: Retain character (0-10) = 8, Std 3: Physical record (0-10) = 6, Std 4: Preserve features (0-10) = 7 = 6 input(s) provided
  2. Calculate Average score
    Average score = round(avgScore * 100) / 100
    7.1 = 7.1
  3. Calculate Compliance
    Compliance = round((avgScore / 10) * 10000) / 100
    71 = 71
  4. Calculate Passes review
    1 = 1

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