FORMULA SHELF
12 of 370
The arithmetic behind the work: what to measure, what to type in, and what the answer comes out as. Every formula says what the symbols mean and gives a worked example, so you can check it against a job you have already done.
SHELVES
Finance
12 formulas
How many pens, bales, litres or hours you must sell before covering fixed costs.
Fixed 900, price 12, variable 7: break-even 180 units.
A more realistic fall in value for vehicles and electronics that lose value fastest early.
20000 at 20% for 3 years = 10240 book value.
Comparing loans or savings with different compounding periods on a like-for-like basis.
12% monthly compounds to 12.68% effective.
Convenience only. Double-check the result against the worked example or a second method before you use it.
What a sum grows to with compound interest, or what a herd or woodlot will be worth.
1000 at 7% for 10 years = 1967.
Convenience only. Double-check the result against the worked example or a second method before you use it.
What regular savings or reinvested profits accumulate to over time.
100 a month at 0.5% for 60 months = 6977.
Convenience only. Double-check the result against the worked example or a second method before you use it.
Comparing costs or savings across years after inflation. A higher nominal figure may buy less.
1000 in 5 years at 3% inflation is worth 863 today.
The fixed payment that clears a loan over a set number of periods.
10000 at 6% over 5 years is about 193 per month.
Convenience only. Double-check the result against the worked example or a second method before you use it.
Pricing produce, meat, feed and workshop work without confusing margin with markup.
Cost 8, sell 10: markup 25%, margin 20%.
Whether a project is worth doing after allowing for the time value of money. Positive is good.
A 5000 investment returning 6000 next year at 8% has NPV 555.
How long before a machine, shed or solar array pays for itself. Ignore interest for a quick check.
A 6000 machine saving 1500 a year pays back in 4 years.
What a future payment or saving is worth today. Use it to compare investments.
1967 in 10 years at 7% is worth 1000 today.
Convenience only. Double-check the result against the worked example or a second method before you use it.
Spreading the cost of a machine evenly over its working life.
20000 cost, 4000 salvage, 8 years = 2000 a year.
SOURCES & PROVENANCE
1 listed
This page is an AI-organised index. The label means the grouping and cross-links were compiled with AI; the information itself comes from the public-domain books, reports and manuals listed below. Open any source to read the local copy or follow the link to the original publication.