Waste Percentage Calculator
Work out the waste rate you actually achieved, from what you bought and what the project used, and what that waste cost.
At a glance
- What you enter
- Material bought, Material in the finished project, Price per unit, Share of the waste you will reuse, Useful items produced, Waste rate you planned for
- What you get
- Material not in the finished project, Waste rate you achieved, Efficiency rate, Waste kept as stock, Waste genuinely lost, Cost of all the waste, Cost of the waste you lost, Cost of the material bought, Material cost in the finished project, Uplift the lost waste adds to the material cost, Effective cost per unit in the product, Material cost per item including the lost waste, Lost waste carried by each item, Your plan against the outcome
- Formula shown
- Yes, every step, right below your results.
- Cost and privacy
- Free, no account needed, and nothing you type is stored.
See worked examples ↓ Read the FAQ ↓ Share this calculator ↓
Results are estimates for general information only, always verify with a professional or official source before acting on them.
How to use the Waste Percentage Calculator
- 1 Enter Material bought (units), Metres, square metres, sheets, grams, rolls. Whatever unit the price is for.
- 2 Enter Material in the finished project (units), The amount actually in the finished item, measured if you can.
- 3 Enter Price per unit, The price for one metre, one sheet, one kilogram, one roll.
- 4 Enter Share of the waste you will reuse (%), Offcuts big enough for another project are stock, not waste.
- 5 Enter Useful items produced, Used for the material cost per item.
- 6 Enter Waste rate you planned for (%), The allowance you actually used when buying. The comparison shows whether the planning was right.
- 7 Press Calculate. You get Material not in the finished project, Waste rate you achieved, Efficiency rate, Waste kept as stock, Waste genuinely lost, Cost of all the waste, Cost of the waste you lost, Cost of the material bought, Material cost in the finished project, Uplift the lost waste adds to the material cost, Effective cost per unit in the product, Material cost per item including the lost waste, Lost waste carried by each item, Your plan against the outcome, and every intermediate step stays visible under "How is this calculated?"
- 8 Change one number at a time to see what moves the result, that is usually the most useful thing a calculator can tell you.
Worked examples
Real numbers run through this calculator. Open any example to load it into the form above and change it.
Ten metres bought, eight and a half used
Material at 12 a metre with no reuse.
You enter
- Material bought
- 10 units
- Material in the finished project
- 8.50 units
- Price per unit
- $12.00
- Share of the waste you will reuse
- 0%
- Useful items produced
- 1
- Waste rate you planned for
- 10%
You get
- Material not in the finished project
- 1.50 units
- Waste rate you achieved
- 15.0%
- Efficiency rate
- 85.0%
- Waste kept as stock
- 0.00 units
- Waste genuinely lost
- 1.50 units
- Cost of all the waste
- $18.00
- Cost of the waste you lost
- $18.00
- Cost of the material bought
- $120.00
- Material cost in the finished project
- $102.00
- Uplift the lost waste adds to the material cost
- 17.6%
- Effective cost per unit in the product
- $14.12
- Material cost per item including the lost waste
- $120.00
- Lost waste carried by each item
- $18.00
- Your plan against the outcome
- -5.0%
A 15 percent waste rate against a planned 10 percent, so the material cost of the product carries an 18 percent uplift and 18 of the 120 spent went nowhere.
A cutting heavy project with reusable offcuts
Twelve square metres bought, eight used, 40 percent of the waste kept.
You enter
- Material bought
- 12 units
- Material in the finished project
- 8 units
- Price per unit
- $22.00
- Share of the waste you will reuse
- 40%
- Useful items produced
- 4
- Waste rate you planned for
- 25%
You get
- Material not in the finished project
- 4.00 units
- Waste rate you achieved
- 33.3%
- Efficiency rate
- 66.7%
- Waste kept as stock
- 1.60 units
- Waste genuinely lost
- 2.40 units
- Cost of all the waste
- $88.00
- Cost of the waste you lost
- $52.80
- Cost of the material bought
- $264.00
- Material cost in the finished project
- $176.00
- Uplift the lost waste adds to the material cost
- 30.0%
- Effective cost per unit in the product
- $33.00
- Material cost per item including the lost waste
- $66.00
- Lost waste carried by each item
- $13.20
- Your plan against the outcome
- -8.3%
A 33 percent waste rate, but 40 percent of it is stock, so the net loss is 2.4 square metres and about 53 of the 264 spent.
A well calibrated production run
Fifty metres bought and 44 used across ten items.
You enter
- Material bought
- 50 units
- Material in the finished project
- 44 units
- Price per unit
- $6.00
- Share of the waste you will reuse
- 0%
- Useful items produced
- 10
- Waste rate you planned for
- 12%
You get
- Material not in the finished project
- 6.00 units
- Waste rate you achieved
- 12.0%
- Efficiency rate
- 88.0%
- Waste kept as stock
- 0.00 units
- Waste genuinely lost
- 6.00 units
- Cost of all the waste
- $36.00
- Cost of the waste you lost
- $36.00
- Cost of the material bought
- $300.00
- Material cost in the finished project
- $264.00
- Uplift the lost waste adds to the material cost
- 13.6%
- Effective cost per unit in the product
- $6.82
- Material cost per item including the lost waste
- $30.00
- Lost waste carried by each item
- $3.60
- Your plan against the outcome
- 0.0%
A 12 percent rate against a planned 12, so the allowance is accurate, and the true material cost is 30 an item against 26.40 of material actually used.
Guides that go with it
The Complete Handcraft Measurement Guide for Beginners
If you are new to crafting, measuring is usually the first place things go sideways: a cut is 3 mm short, two "identical" squares are not identical, or a pattern that looked fine on paper does not fit...
How to Avoid Wasting Materials When Making Crafts
Most craft waste is not caused by clumsy hands. It is caused by decisions made before you pick up a tool: buying too much, cutting before measuring, or starting a project with no plan for the offcuts....
How to Fix Common Handmade Crafting Mistakes
You just finished a project and something went wrong. Maybe a seam puckered, a wood joint gaps, glue oozed where it shouldn't, or the paint dried with brush marks. This guide walks you through the fix...