How to Fill In the Before and After Cost Tables So the Saving Percentage Comes Out Right

How to enter each line in the current-state and optimized cost tables - item name, standard code, brand, monthly volume, cycle time - so the system computes the saving percentage, ROI and payback correctly.

Updated September 5, 2026

Costdown works out the saving percentage by comparing two tables: the cost before the change and the cost after it. The guide "" + tenCategories.title + "" explains what the TEN COST CATEGORIES are; this one explains how to type each LINE inside those categories correctly - the part everyone meets, whichever category they are filling in.

Open only the categories your case actually touches

Neither table asks for all ten categories. Pick the ones your improvement really touches and add lines there - a typical case affects one or two, not ten.

An improvement can make a category APPEAR on the after side that did not exist before (an added machine, say), or make a before-side category DISAPPEAR after (scrap gone entirely). The two tables are not required to open the same categories.

Row name

A label so you and your readers can tell what this row is. It does not affect the calculation.

Worth setting on every row, and essential when a category has several rows — without it you will not remember which is which.

'Lathe operator', 'CNC machine #3', 'SS400 steel, 10 mm plate'.

You can put internal part codes, machine numbers, team names or process step names here — whatever helps a reader match this to your actual shop floor.

Standard group

The industry standard code for a material or machine. Choosing it is what makes your case study comparable with other people's.

Choose when you find an exact or close match. If nothing fits, choose OTHER and write the real name in the Row name field — never pick a roughly similar code, because that corrupts comparison data in a way nobody can detect later.

SS400 (Japan) = S235JR (Germany) = A36 (USA) = Q235 (China) — four codes, one statistical group.

The search box accepts alternative names: typing '1.4301' finds SUS304, and so does 'stainless 304'. You do not need to know your country's code.

Manufacturer

Who made this material or tool. Optional, but genuinely useful.

Enter it when you know. Leave blank for unbranded or unknown supply. For cutting tools it is strongly recommended — two brands sharing one ISO code can differ severalfold in life and price.

Same CNMG120408 insert: Sandvik 4325 and Korloy PC9030 differ sharply in both price and life.

Recording the brand is the only way to later answer 'which brand would be cheaper and still work'.

Monthly volume (pcs)

How many pieces this step produces in a month.

Always required. Use the real average of recent months, not the machine's rated capacity — capacity is what it could do, volume is what you actually do.

1,500 pieces a month → enter 1500. If volume swings, take a 3-month average.

If you work in batches rather than evenly per month, convert: 3,000 per quarter → enter 1000. For a product passing through MULTIPLE serial processing steps, each with its own scrap rate: the volume at the FIRST step must be LARGER than the final delivered volume — it must cover the scrap of EVERY step downstream of it. Work backward from the last step: volume at the earlier step = volume at the later step / (1 - the later step's scrap rate). Entering the same volume for every step (without working backward) understates the cost of the earlier steps.

Workload (pcs) (labor lines only)

How many pieces this person handles in a month.

Always required. If they handle several products, enter only the share belonging to the product being costed — not their total output.

They make 1,000 of this part number → enter 1000, even if they also make 2,000 of another.

If one person tends several machines, enter the pieces they actually handle at this step — the time sharing is already captured by cycle time. For a SERIAL MULTI-STATION line (assembly): every station's monthly volume must use the SAME figure — the line's real throughput, capped by the SLOWEST station (the takt time) — not each station's own maximum speed. A fast station costed at its own cycle time will overstate its labor cost, because in reality it has to wait on the slow station.

Cycle time (seconds)

Seconds needed to complete one piece at this step.

Always required. Time it several times and average. Do not use the catalogue figure — that assumes ideal conditions with no setup, tool change or waiting.

45 seconds to turn a shaft → enter 45. If one clamping makes 2 pieces in 80 seconds → enter 40.

If your step is measured in minutes or hours, convert: 2 minutes = 120, 1.5 hours = 5400.

Calculation settings are shared by both tables

The "Calculation settings" block - working days per month, shifts, hours per shift, efficiency - appears ONCE on the form, above both tables. It is not filled in separately for before and after.

The reason: it is the denominator that spreads labor and machine cost across each unit on BOTH sides. If the shift pattern genuinely changes with the improvement (three shifts down to two, say), show that through the cost lines themselves - fewer labor lines, fewer machine hours - rather than by editing the shared settings. Editing the shared block recalculates the before side too, and corrupts the baseline you are measuring against.

After both tables are filled in

The system adds the lines within each category, adds the categories into a cost per unit for each side, then takes the difference between before and after as the saving percentage. You never do a sum by hand.

If a category or a line is left blank, read the guide on the six fields below before publishing - most of them make the cost look cheaper than it is, with no warning at all.

Related guides

The Ten Manufacturing Cost Categories, in Production Order
The ten cost categories Costdown uses to price a product — material, machinery, labor, tooling, scrap, rework, outsourced processing, packaging, logistics, factory overhead — with the formula and a worked example for each.
Six fields almost nobody fills in, and which way each one bends the cost
Material yield, personal and machine allowances, energy, units per pack and fixed cost per lot: six inputs that are usually left empty, and why five of the six make the cost look cheaper than it is.