APPORTION
LIMITED PLACES · EXPLAINABLE CHOICES

Who gets the next seat?

Sharing workshop places, club seats or another limited pool? Enter your groups, compare three proportional rules and take a clear brief to the discussion. The numbers explain trade-offs; your group decides.

  1. Agree what the weights mean.
  2. Apply your groups and available places.
  3. Compare, discuss and save your inputs.
Your inputs stay in this tab. Save them before leaving.
Applied allocation

Hamilton

25 / 25 seats
Whole seats awarded Ideal fractional quota
7A · Group AQuota ≈ 7.353
7B · Group BQuota ≈ 7.353
4C · Group CQuota ≈ 4.412
3D · Group DQuota ≈ 2.451
3E · Group EQuota ≈ 2.451
1F · Group FQuota ≈ 0.98
25 → 26 seats

D · Group D and E · Group E lose a seat as the pool grows. The next allocation is recomputed from the same weights.

This is a house-size paradox. Changing the pool changes both whole quotas and remainder rankings.

No tie crosses the last-seat cutoff.

Earlier equal priorities may change award order without changing the final totals. Inspect the trace below.

Same inputs. Different rules.

Compare the allocations

4 groups receive different totals across the rules

This compares the same weights, number of places and tie priorities. Agreement here does not mean the rules always agree.

  • Group A [A]: Hamilton 7 · D’Hondt / Jefferson 8 · Sainte-Laguë 8. Range 78 places.
  • Group B [B]: Hamilton 7 · D’Hondt / Jefferson 8 · Sainte-Laguë 8. Range 78 places.
  • Group D [D]: Hamilton 3 · D’Hondt / Jefferson 2 · Sainte-Laguë 2. Range 23 places.
  • Group E [E]: Hamilton 3 · D’Hondt / Jefferson 2 · Sainte-Laguë 2. Range 23 places.

Use the brief to discuss the differences, then record your group’s chosen rule and rationale separately. It is not a decision made on your behalf.

Quota = 25 × group weight / 5,100. Decimals are rounded only for display; allocation comparisons use exact integer arithmetic.
GroupWeight shareExact quotaHamiltonD’Hondt / JeffersonSainte-LaguëSelected rule vs quota
A · Group A29.412%37500 / 51007.353 · bounds 78728% of seats832% of seats832% of seats-0.353 seatsWithin lower/upper quota
B · Group B29.412%37500 / 51007.353 · bounds 78728% of seats832% of seats832% of seats-0.353 seatsWithin lower/upper quota
C · Group C17.647%22500 / 51004.412 · bounds 45416% of seats416% of seats416% of seats-0.412 seatsWithin lower/upper quota
D · Group D9.804%12500 / 51002.451 · bounds 23312% of seats28% of seats28% of seats+0.549 seatsWithin lower/upper quota
E · Group E9.804%12500 / 51002.451 · bounds 23312% of seats28% of seats28% of seats+0.549 seatsWithin lower/upper quota
F · Group F3.922%5000 / 51000.98 · bounds 0114% of seats14% of seats14% of seats+0.02 seatsWithin lower/upper quota
Hold weights and priorities fixed

Where does adding a seat cause a loss?

40 transitions

Checks every adjacent total from 1 → 2 through 199 → 200 using Hamilton. Selecting a transition applies its starting total; it does not apply unfinished group edits.

Show the arithmetic

Whole quotas, then remainder seats

quota = seats × weight / total weight

Allocate each whole quota, then give the remaining seats to the largest remainders. Recompute the entire allocation when the seat total changes.

Inspect whole quotas and all 6 remainder ranks

Whole-quota seats: A = 7 · B = 7 · C = 4 · D = 2 · E = 2 · F = 0. “Extra” means one of the remaining seats, not a sequential allocation across changing house sizes.

RankGroupExact remainderExtra seatEqual remainder groups
1F5000 / 5100YesNone
2D2300 / 5100YesD, E
3E2300 / 5100YesD, E
4C2100 / 5100NoNone
5A1800 / 5100NoA, B
6B1800 / 5100NoA, B

What the numbers do not decide

Proportionality is one principle, not a complete definition of fairness. Group weights do not express need, rights or the quality of representation.

Lower and upper quotas are the ideal share rounded down and up. They coincide when the quota is already a whole number. Hamilton stays between these bounds; divisor rules can exceed them. A rule’s behavior is a tradeoff to examine, not a verdict.

Educational proportional-allocation model; not a full election system or a universal fairness score. No thresholds, guaranteed seats, district boundaries, eligibility rules or real-world tie procedures. Inputs stay in this browser unless you download them.

Primary sources

Reviewed 8 September 2026. The lab uses the core formulas, not each jurisdiction’s complete election rules. The fixed tie convention is ours.