Sheet metal calculators for press brake buyers
Four calculators covering the numbers that decide whether a machine works for you: tonnage, developed length, V-opening, and which machine line matches your constraints.
Pick a calculator
Press brake tonnage calculator
Enter material, thickness, bend length and V-opening to get the tonnage you actually need — and the figure to plan against once you add a margin.
Bend allowance & blank length calculator
Works out bend allowance, bend deduction and developed flat length from thickness, inside radius, bend angle and K-factor.
V-die selector
Which V-opening suits your sheet thickness, what the minimum bend flange becomes, and how the tonnage per foot changes with it.
Machine selector
Tell us your tonnage, part depth, bed length, axis count and available power. It tells you which machine line fits, and where it does not.
What these numbers are, and what they are not
Every calculator here uses published industry formulas — the tonnage figure comes from the standard air-bending relationship between thickness, length and V-opening, and the bend allowance from the K-factor method. They are the same relationships you will find in any press brake tooling catalogue.
Treat the output as a planning figure, not a specification. Real tonnage moves with the alloy and its temper, the actual condition of your tooling, the speed you run, and whether you are air bending, bottoming or coining. Real developed length moves with how much the material springs back. That is normal, and it is why every result here comes with the assumptions printed next to it.
We do not ask for an email to use them, and nothing you type leaves your browser.
Where these fit against buying a machine
The calculators answer the arithmetic. They do not answer the judgement — and the judgement is where most first-time buyers lose money. The guides below cover that part:
- Can you run a press brake on 220V single phase? — What single phase power actually limits, where the practical ceiling sits, and when a phase converter is the answer.
- How much tonnage does a press brake need? — Why tonnage is the wrong starting point, what actually drives the force requirement, and how to size a machine from the part you need to bend.
- Why your press brake tooling affects accuracy more than you think — Angle drift, marking, tool clamping systems, and a diagnostic order for when bends stop coming out right.
- Used press brake or new? An honest comparison — Where used equipment genuinely makes sense, what it costs you that is not on the listing, and what to check before you buy.
- What to prepare before your press brake arrives — Power, lifting, floor loading, levelling, and an acceptance checklist to run through on delivery day.
- Press brake electrical requirements: voltage, amps and breaker sizing — What 208V, 240V and 480V three phase services mean for a hydraulic machine, how to work out full-load current, and the questions to ask before the electrician shows up.
- How to buy a press brake: a buyer’s guide for US shops — Define the part envelope, write a spec, compare quotes line by line, and run an acceptance checklist before final payment.
- Importing a press brake from China: shipping, duty, lead time and real costs — Landed cost line by line: freight options, HTS classification and Section 301 duties, realistic lead time, installation costs, and the terms worth insisting on.
- Press brake size guide: tonnage vs bed length — Why 4 ft and 60 ton are two different questions, how bed length drives the tonnage you need, and what each bed length suits.
- Bend allowance, bend deduction and K-factor explained — The formulas, a typical K-factor chart, and a worked example that gets the same flat pattern two different ways.
- Press brake tooling guide: punches, dies and clamping systems — What European, Amada-style, Wila, Trumpf and American tooling actually are, why they are not interchangeable, and which die types solve which part problems.
- Press brake specifications explained: how to read a spec sheet — Which numbers matter, why ±0.01 mm claims need their test conditions, what crowning and backgauge axes do, and what spec sheets leave out.
- Press brake troubleshooting: symptoms, causes and what to check first — Symptom-first diagnosis for ram drift, lost pressure, inconsistent angles and CNC faults — what to check yourself and what needs a technician.
- Bending stainless steel on a press brake — Springback, work hardening and marking: why stainless needs different tooling and technique, and how to compensate.
- Box and pan brake: what it is and when you need one — Why the frame beats you to boxes rather than the tonnage, and the finger tooling that makes enclosures, ductwork and cable trays possible.
- Sheet metal brake vs press brake: types, terms and which one you need — Cornice, finger, box and pan, press brake — what each machine can actually form, and how to pick by part profile.