General Purpose Calculators
A home for the everyday tools that don't fit a single trade — from construction materials like bitumen and MOT Type 1 sub-base to a baseball ERA calculator and a flexible rounding tool. Fast, accurate, and free to use.
Last updated: · Reviewed by the OtherCalculators editorial team
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Which general calculator do you need?
- I need sub-base tonnage for a drive, patio or path
- MOT Type 1 Calculator — MOT Type 1 aggregate in tonnes and cubic metres, with wastage
- I'm working out bitumen or binder quantities
- Bitumen Calculator — quantity, weight, binder content and spray rate for bituminous work
- I want a baseball pitcher's earned run average
- ERA Calculator — ERA from earned runs and innings, with innings-plus-outs input
- I need to round a number to a set precision
- Rounding Calculator — nearest whole number, decimal places, or significant figures
Available Tools
4 Calculators AvailableERA Calculator
Calcualte Earned Runs Average (ERA) for pitchers.
Rounding Calculator
Round numbers to the nearest whole number, decimal, or significant figure.
Bitumen Calculator
Estimate bitumen quantity, volume, weight, asphalt binder content, spray rate, and roofing rolls.
MOT Type 1 Calculator
Estimate how much MOT Type 1 sub-base you need in tonnes and cubic metres.
What this category covers
Unlike the site's other categories, this one has no shared method to explain — its tools are grouped because they are each genuinely useful and none of them belongs to a trade cluster, not because they compute anything in common. Two are construction-material estimators (bitumen and MOT Type 1 sub-base), one is a baseball statistic (ERA), and one is a general-purpose rounding tool. Treat the category as a shortlist of standalone utilities rather than a topic with a single answer.
Because there is no common formula, the honest guidance is per tool, and it lives on each calculator's own page: worked examples, reference tables, and the assumptions behind every figure. What the hub can usefully do is route you to the right one and flag the mistakes that recur across the material tools — where units and wastage catch people out — which is what the sections below do.
How these tools group
Three unrelated clusters, listed by what you are trying to work out. Construction materials covers the two paving-adjacent estimators; sports statistics is the single ERA tool; and everyday maths is the rounding calculator, which is the one tool here that supports the others — it tidies an ERA to two decimals or a material estimate to a sensible precision.
Construction materials2 tools
Sports statistics1 tool
Everyday maths1 tool
Common mistakes with these tools
- Mixing up your units on the material tools. Convert depths in millimetres to metres before multiplying, or the volume — and the tonnage that follows — comes out a thousandfold too large. The NIST unit conventions the rounding tool follows are the same ones the material estimates assume.
- Ordering aggregate or bitumen with no wastage allowance. Add 5–10% for spillage, compaction and site variation so you don't under-order and stall the job on a part load.
- Confusing the sub-base with the surface. The MOT Type 1 calculator sizes the granular layer under a drive, not the tarmac on top of it. Those are different materials ordered at different densities — the surface itself belongs to the tarmac tools.
- Entering innings as a plain decimal on the ERA tool. In baseball, 6.2 means six innings and two outs, not six-and-two-tenths. Enter innings the way the box score records them so the earned run average comes out right.
- Over-rounding before the final step. Round once, at the end. Rounding an intermediate figure and then carrying it forward pushes the error into the result — decide the precision you actually need, then apply it last.
General calculator FAQs
What calculators are in the general category?+
This section collects everyday tools that don't belong to a single trade — currently a bitumen calculator, an MOT Type 1 sub-base calculator, an ERA (earned run average) calculator for baseball, and a rounding calculator. They span construction materials, sports statistics, and basic maths.
Which tool do I use to work out sub-base material?+
Use the MOT Type 1 calculator. It estimates the tonnes and cubic metres of granular sub-base for a driveway, patio, path, or shed base by multiplying your dimensions by depth and a standard aggregate density, then adding a wastage allowance.
How do I calculate a pitcher's ERA here?+
Use the ERA calculator. It applies ERA = (9 × earned runs) ÷ innings pitched and accepts innings entered as decimals or as innings-plus-outs (for example 6.2 means six innings and two outs). In modern MLB, an ERA under 4.00 is solid and under 3.00 is elite.
What does the rounding calculator do?+
It rounds a number to the nearest whole number, a set number of decimal places, or a number of significant figures — handy for tidying a result such as an ERA to two decimals or a material estimate to a sensible precision.
Are these calculators free to use?+
Yes. Every tool in the general category is free, needs no sign-up, and runs entirely in your browser.
Why are a baseball statistic and a sub-base calculator in the same category?+
Because the general category is a deliberate catch-all, not a topic. It holds useful tools that don't fit one of the site's trade categories, so its members share no formula and no inputs — a pitcher's ERA and a driveway's sub-base tonnage have nothing in common beyond both being quick things people need to work out. Pick by the job you have rather than by a theme, and each tool links to a full explainer with worked examples.
Which of these general calculators suit a UK paving project?+
The MOT Type 1 and bitumen calculators. MOT Type 1 estimates the granular sub-base tonnage under a drive, patio or path, and the bitumen calculator covers binder and spray quantities. For the tarmac surface itself, and for driveway installation and repair costs, use the dedicated tarmac calculators, which share the same build-up.
Related categories
- Tarmac Calculators (5) — where the paving surface itself is priced and quantified — the MOT Type 1 and bitumen tools here estimate the sub-base and binder that sit under a tarmac drive
- Asphalt Calculators (25) — the US-units equivalent of the same paving work, if you are estimating in tons and square feet rather than tonnes and square metres
Estimates & assumptions
- These tools are independent; nothing here shares inputs or a formula, so guidance is per calculator and lives on each tool's own page.
- Material estimates assume standard densities and require consistent units — convert millimetres to metres before multiplying, and add a 5–10% wastage allowance before ordering.
- The ERA calculator follows the standard MLB definition and expects innings entered as innings-plus-outs (6.2 = six innings, two outs).
- The MOT Type 1 tool sizes a granular sub-base only, not the tarmac surface above it, which is estimated by the tarmac calculators.
These tools produce estimates for planning only. Confirm material quantities against your supplier's figures before ordering.