Free · Everyday planning calculators

Toilet Roll Supply Planner

Estimate whole rolls and packs or the duration of an existing supply.

  • Formula & worked example
  • Private in your browser
  • No signup
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

Four rolls at a total allowance of 0.4 rolls daily last ten days, or until January 11 from a January 1 start.

Required rolls = ceiling(people × days × daily roll allowance)

Worked example

Enter these known values and leave the other values blank.

I want to know...
how long will my supplies last
People
2
which is...
4 rolls
Bought on
2024-01-01
Paper use
🧻 (not much)
Rolls per pack
4
I bought...
1 packs
You're safe until
2024-01-11
💧
560 L of water
🌳
2.7 kg of wood

Assumptions and limitations

  • Daily roll-use options are illustrative planning rates; roll sizes and household use vary. Required rolls and purchase packs round up. The captured water and tree-mass figures are fixed footprint equivalents, not verified claims about your paper manufacturer.

Common questions

What assumptions affect this result?

Daily roll-use options are illustrative planning rates; roll sizes and household use vary. Required rolls and purchase packs round up. The captured water and tree-mass figures are fixed footprint equivalents, not verified claims about your paper manufacturer.

Can I solve for a missing value?

Clear the missing field and enter compatible known values in the displayed units. Supported inverse branches remain available; rounding and one-way outputs keep their original direction.

References

Replace captured external illustrations with original accessible explanations of the measurements, allowances and selected order, preserving every variant condition and all controls. Require whole people, pack sizes and supplied roll counts while preserving the captured positive bounds. Keep pack size editable in both purchasing and stock-duration modes; the captured purchasing mode hid the pack size used by its pack-count equation.

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